Science Science for for South South AfricA AfricA
ISSN 1729-830X ISSN 1729-830X
Volume 8 • Number 1 • 2012 Volume 3 • Number 2 • 2007 r29.95 r20
Deep time and tectonic plates: how the Earth formed Earth's early history and the Barberton granites Science rocks especially in science clubs Predators on the ancient pampas The coelacanth: old four legs Massive compact objects: black holes
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The moving Earth Quest looks at how the Earth was formed 8
The Barberton granites South Africa has a rich record of Earth’s history in the Barberton granites. Quest explains how earth scientists are uncovering the evidence
Teaching science Quest finds out how science clubs can make science rock
Not so set in stone – Coelacanth: the fossil that really came to life
Contents Volume 8 • Number 1 • 2012
Penny Hawworth tells the exciting story of the fish that everyone thought was extinct
Wilmot James explains how the Pinot Noir grape has given scientists and wine makers a lot to think about
Terrestrial predators, mammal-like reptiles and the pampas A team of palaeontologists, including South Africans, have uncovered evidence of one of the earliest land predators. Quest tells the story
Grapes, genes and climate change
Real-life problem solving Quest’s resident mathematician, Steve Sherman, shows us how to love maths
Of butterflies and bumpy black holes Marisa Geyer and Jeandrew Brink tell us about extremely massive compact objects
String theory – p. 36
A voice for young scientists in South Africa Caradee Wright, Genevieve Langdon and Penny Moore tell us about the launch of an exciting new venture for young South African scientists
Young scientists excel – p. 15 • Dinosaur nursery – p. 27 – A watery planet – p. 45 • Worms wage war on waste – p. 49 • Campus brewed – p. 49 33
Careers Becoming a geologist
What’s faster than light? Chris Clarkson asks the question
Africa Geographic Too clever by half – p. 33 • Think before you walk – p. 43
How little we know Chris Clarkson explains how little we know about our universe
Diary of events
Nanotechnology and nanoparticles: should be concerned about our health?
Riëtha Oosthuizen discusses the possible health implications of nanoparticles
Back page science • Mathematics puzzle
Quest 8(1) 2012 1
Science Science for for South South AfricA AfricA
ISSN 1729-830X ISSN 1729-830X
Volume 8 • Number 1 • 2012 Volume 3 • Number 2 • 2007 r29.95 r20
Deep time and tectonic plates: how the Earth formed Earth's early history and the Barberton granites Science rocks especially in science clubs Predators on the ancient pampas The coelacanth: old four legs Massive compact objects: black holes
Sc A c AAcdAedmeym yo fo fS c I eI eNNccee ooff SS o u u tt hh AAffrrI c I cA A
Images: NASA, SKA, SLCA(UWC) and Deviant Art.
SCIENCE FOR SOUTH AFRICA
Editor Dr Bridget Farham Editorial Board Roseanne Diab (University of KwaZulu-Natal) (Chair) Michael Cherry (South African Journal of Science) Phil Charles (SAAO) Anusuya Chinsamy-Turan (University of Cape Town) George Ellis (University of Cape Town)
Correspondence and The Editor enquiries PO Box 663, Noordhoek 7979 Tel.: (021) 789 2331 Fax: (021) 789 2233 e-mail: firstname.lastname@example.org (For more information visit www.questinteractive.co.za) Advertising enquiries Barbara Spence Avenue Advertising PO Box 71308 Bryanston 2021 Tel.: (011) 463 7940 Fax: (011) 463 7939 Cell: 082 881 3454 e-mail: email@example.com Subscription enquiries Patrick Nemushungwa and back issues Tel.: (012) 349 6624 e-mail: Patrick@assaf.org.za Copyright © 2012 Academy of Science of South Africa
‘Being a young scientist at school is tough because no one gives us the time to absorb the things we could do with all this information. We learn so many interesting things about nature and science but sometimes I am confused as to where it fits in. I’m so focused on learning my textbook that I never see behind the formulas and discoveries to where we can go with this information. No one will listen to a 16-year-old's opinion. There is so much I want to do but so little space to do it. What if we never get the opportunity?’ (Daisy, Grade 11). This young woman is passionate about science, but overwhelmed by the crowded science curriculum. She is also probably bombarded daily by ‘bad science’, myths and superstitions in newspapers and magazines. So, it is hardly surprising that she worries about future opportunities. This issue of Quest is packed with different varieties of science – everything from earth sciences to nanotechnology to astrophysics. Science rocks – it truly does. A science education opens the doors of the world. So how can we help Daisy and others like her – young people who love science – but who find that they have no idea what they can do with it, or where it fits into their world? In this issue of Quest Prof Shaheed Hartley shows how school science clubs can help people – students and teachers – understand where science fits into our daily lives. Students who get involved in science clubs go way beyond the curriculum when they start to explore, for example, aspects of physics or chemistry that they find particluarly interesting. Or perhaps someone has a telescope and they spend time looking at the stars and finding our more about the universe we are part of. Field excursions can introduce you to the practical aspects of biodiversity – how indigenous vegetation and animals can be mixed into an agricultural environment, how a new development next to a wetland can be catastrophic, or environmentally sensitive, depending on how the development is planned and executed. Our science curricula are crowded – no doubt about it. The pressure to do well is intense in an increasingly competitive world and you have to make choices at a time of your life when the enormous range of options seems at its most confusing. The good news is that it doesn’t really matter which branch of science you decide to enter straight out of school – it all rocks! And when you have your first science qualification in the bag, the world really is open to you and you can become part of making it a better place for everyone.
Bridget Farham Editor – QUEST: Science for South Africa Join Quest’s knowledge-sharing activities Write letters for our regular Letters column – e-mail or fax your letter to The Editor. (Write QUEST LETTER in the subject line.) ■ Ask science and technology (S&T) questions for specialist members of the Academy of Science to answer in our regular Questions and Answers column – e-mail or fax your questions to The Editor. (Write QUEST QUESTION in the subject line.) ■ Inform readers in our regular Diary of Events column about science and technology events that you may be organising. (Write QUEST DIARY clearly on your e-mail or fax and provide full and accurate details.) ■ Contribute if you are a specialist with research to report. Ask the Editor for a copy of QUEST’s Call for Contributions (or find it at www.questsciencemagazine.co.za), and make arrangements to tell us your story. To contact the Editor, send an e-mail to: firstname.lastname@example.org or fax your communication to (021) 789 2233. Please give your full name and contact details. ■
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The moving Earth Earth sciences, which include geology, involve the study of the Earth – and all its components. Quest takes a look at how this all fits together.
he Earth has not always been the way it is now. The Earth’s crust (and below) is a dynamic and shifting system – we are reminded of this every time there is an earthquake or a volcano. The geology of South Africa is particularly rich in rocks that allow earth scientists to understand the earliest preserved parts of the long history of our planet.
Geological time One thing that you have to understand before you can start to appreciate geology is the concept of geological time – also called deep time. Geologists and other scientists started to truly understand geological time in the 18th century when they started to produce geological maps. As they produced the maps, they realised that rocks, particularly sedimentary rocks, could be arranged in the order in which they were deposited – the younger layers on top and the older layers below. They also looked at the types of fossils that the rocks contained – mainly formed by the shells, bones and teeth of marine organisms. The fossils changed through the rock layers – there were sudden changes in the types and varieties of species present. Early geologists gave names to the broad intervals that had similar fossil types, which are still used today. After Charles Darwin and Alfred Wallace published their important works on evolution, scientists realised that the changes in the fossils came about through evolution and that these changes took place over long – really long – periods of time. Much later – when radioactive dating techniques were discovered – scientist were able to find out just how much time was involved. In a standard geological time scale, Eons represent very long periods, Eras are slightly shorter periods and Periods and Epochs are even shorter (relatively speaking).
Diagram of geological time scale, where the past is toward the bottom of the spiral.
Image: Wikimedia commons
This clock representation shows some of the major units of geological time and definitive events of Earth’s history. The Hadean eon represents the time period older that the preserved solid rock record; its lower (younger) boundary is now regarded as 4.0 billion years ago. Other subdivisions reflect the evolution of life; the Archean and Proterozoic are both eons, the Palaeozoic, Mesozoic and Cenozoic are eras of the Phanerozoic eon. The two million year Quaternary period, the time of recognisable humans, is too small to be visible at this scale.
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Classification of rocks Rocks are made up of minerals and form in different ways. There are two ways in which most rocks are formed. The first is by crystallisation from a molten state, which produces igneous rocks. The second is by the build-up of particles of sediment or by chemical precipitation, producing sedimentary rocks. Igneous or sedimentary rocks that have already formed may undergo pressure and temperature changes as they are buried or deformed. This causes the minerals in the rock to change to form new minerals that are stable in the new conditions. These are called metamorphic rocks. Each type of rock has a characteristic mineral combination and structure and you can learn to tell one from another by using field guides.
This diagram shows a cut-away section through the Earth, showing the component parts. Image: Wikimedia commons
Granite – an igneous rock with high concentration of silico, sodium and/or potassium – the dominant rock type of the continental crust. Image: Wikimedia commons
Banded iron formation in an iron-rich sedimentary rock commonly containing alternating iron and silica rich bands. It occurs in Barberton, Mpumalanga. Image: Wikimedia commons
A metamorphic rock.
Image: Wikimedia commons
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There are three eons: The Archaean (before 2.5 billion years ago), Proterozoic (2.5 - 540 million years ago) and Phanerozoic (current eon: covers roughly 542 million years). Rocks that are older than the Phanerozoic contain no fossils. The Archaean and Proterozoic are together called the Precambrian. The Phanerozoic is divided into three Eras – the Palaeozoic (ancient life – 542 - 251 million years ago), Mesozoic (middle life – 250 - 65 million years ago) and Cenozoic (recent life – 65 million years ago to the present). This is based on fossil types. Scientists debate whether we have recently entered a new era, the Anthropozoic. This will be the era within which the geological record reflects man’s impact on Earth, through the presence of long lived pollution in sediments, the record of sea level rise induced by our contributions to atmospheric greenhouse gases and the fossil record of the mass extinctions that our activities are causing. The Era boundaries are marked by sudden changes in fossil types, now known to be caused mainly by sudden mass extinction events. The most serious of these was the endPermian mass extinction, in which about 96% of species became extinct. The best-known mass extinction is the end-Cretaceous extinction – the end of the dinosaurs – when about 70% of species became extinct. Our planet The Earth is made up of shells – each shell is different in composition and in physical properties. The main layers are the crust, the mantle and the core. The Earth’s crust is between 7 km and 40 km thick. The mantle is solid –
made up of rocky material that is mainly magnesium, iron, silicon and oxygen. Rocks near the top of the mantle – 100 200 km deep – are close to their melting point because of the temperatures and pressures within the mantle. The boundary between the mantle and the core occurs at around 2 900 km below the surface and is called the Gutenberg Discontinuity. The outer core is a very dense liquid – thought to be molten nickle and iron – and the inner core is thought to be a solid nickle-iron alloy. The temperature increases with depth and the inner core is about 5 500 °C. Iron-nickle alloy melts well below this temperature at the Earth’s surface, but the pressure in the centre of the Earth is so high that the inner core and the mantle are solid. There are two kinds of crust – the continental crust and the oceanic crust. The continental crust is between 30 - 40 km thick, but can be up to 75 km thick under mountain ranges. It is made up mainly of granite and similar rocks rich in silicon, aluminium and potassium. The continental crust contains the remains of older rock masses that have been buckled and bent and subjected to high temperatures and pressures. Some of the oldest rocks on the planet are found in the continental crust – up to 4 100 million years old. The continental crust is largely composed of granitic rocks that have been recycled through the process of erosion, sedimentation, deformation, heating and melting (the rock cycle). The oceanic crust is 6 - 8 km thick and is made up of basalt and related rocks, which are dark igneous rocks rich in magnesium, iron, silicon and oxygen and are denser than the continental crust. The present-day ocean floor is not more than about 200 million years old.
The Kingdom of Lesotho is completely landlocked by the surrounding Republic of South Africa. Major landforms visible in the image include the Qeme and Berea Plateau, and erosional remnants of horizontally layered sedimentary rocks that formed in the Karoo Basin approximately 200 – 229 million years ago during the Upper Triassic Period. Image: NASA
The rigid outer layer of the Earth, called the lithosphere, is made up of several large slabs or plates, which are moving relative to each other. The most intense geological activity – earthquakes, volcanic erruptions – occurs along the boundaries between the plates. Image: Wikimedia commons
Plate tectonics There is overwhelming evidence that the continents were once joined together in a supercontinent, Pangaea (See Terrestrial Predators, mammal-like reptiles and the pampas in this edition of Quest). Plate tectonics grew out of the idea of sea-floor spreading – the idea being that the mid-ocean ridges caused spreading of the sea floor, which moved the continents apart – much like a conveyer belt. This was confirmed when sensitive instruments were able to show
that the magnetic properties on either side of the ocean ridges were the same. Plate tectonics postulates that the outermost shell of the Earth, the lithosphere, is divided into a number of separate, rigid slabs or plates that are moving relative to each other. The zones where the plates are in contact are called plate boundaries. These plate boundaries are marked by earthquakes and volcanic activity. There are often mountain ranges or trenches at the plate boundaries. ▲ ▲
Stratigraphy The next concept that you need to understand to appreciate the complexities – and the fascination – of geology is stratigraphy. The Earth’s crust is not stable. It shifts direction, up and down and sideways, in response to forces generated in the mantle below. Whole continents may be submerged below sea level and then raised and exposed to the elements and weathering. When the crust is submerged below sea level, sediments accumulate, forming sedimentary rock. Different types of sedimentary rock accumulate in response to different conditions, including volcanoes. Some of these conditions can cause subsidence, which results in the formation of layers of sedimentary and igneous rocks. These areas may extend over millions of square kilometres – but can also be small. Geologists have carefully mapped the distribution of sedimentary rocks and their associated volcanic rocks and can identify those rocks that formed with the same period of subsidence. All those rocks that were deposited during the same period of subsidence are grouped together and called a supergroup. Two very important local examples are the Karoo Supergroup and the Witwatersrand Supergroup. In a supergroup, the oldest layers of rock lie at the bottom of a vertical profile through the pile and the youngest at the top. There may be major changes in the prevailing conditions in one period of accumulation, for example from persistent deep water conditions to a long period of shallow water conditions. These changes cause the accumulation of very different types of rocks, so the layers of a supergroup can be further subdivided, depending on the types of rocks present. The subdivisions are Groups, Subgroups, Formations, Members and Beds. Each of these smaller subdivisions is also given a name, usually the name of the place where the rocks are best represented. The study of these groups of rocks and their interrelationships is called stratigraphy.
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The three types of plate boundary.
of this are the Andes mountain range in South America and the Japanese island arc. Plate convergence
The Wilson Cycle.
Image: Wikimedia commons
There are different forms of plate boundaries. 1 Transform boundaries (conservative) occur where plates slide or grind past each other along transform faults. The San Andreas Fault in California is an example of a transform boundary. 2 Divergent boundaries (constructive) occur where two plates slide apart from each other. Mid-ocean ridges (e.g. Mid-Atlantic Ridge) and active zones of rifting (such as Africa’s East African Rift) are both examples of divergent boundaries. 3 Convergent boundaries (destructive) (or active margins) occur where two plates slide towards each other, commonly forming either a subduction zone (if one plate moves underneath the other) or a continental collision (if the two plates contain continental crust). Deep marine trenches are typically associated with subduction zones. The subducting slab contains many hydrous minerals, which release their water on heating; this water then causes the mantle to melt, producing volcanism. Examples
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Plate convergence occurs where plates move towards each other and one plate slides down under the other in a process called subduction. In this process, the creation of a new crust by plate separation results in the destruction of crust elsewhere. Convergent plate margins occur particularly around the edges of the Pacific ocean, which is steadily being consumed as the Atlantic and Indian Oceans expand. Convergence causes the oceanic trenches, which are the deepest parts of the ocean. The island arc of convergent plate boundaries along the Japanese Islands was the source of the earthquake that caused the Japanese tsunami on 11 March 2011. How fast do plates move and what drives them? Plate movement varies from 2 cm per year to more than 20 cm per year. The plate that contains the African continent is stationary and has not moved for the past 30 million years. The energy that drives the plates to move is the Earth’s internal heat that comes from two main sources: the primordial heat generated during the formation of the Earth and heat produced by the radioactive decay
of uranium, thorium and potassium within the Earth. Plate tectonics and the Earth’s history The Earth is 4 600 million years old and the oldest known rocks formed 4 100 million years ago, but all the ocean floors are younger than 200 million years. This means that 60% of the Earth’s surface (the ocean floors) was formed in the last 5% of Earth’s history – the moving Earth. Plate tectonics provides a unifying theory – a framework – in which to interpret and understand geological processes. Plate tectonics has shown us that the continents have been moving for thousands of millions of years and are still doing so. The total area of the continental crust has grown over time by the creation of new crust at subduction zones. We now know that continents move laterally and also rise and fall in the surrounding oceans and sometimes split apart. This takes place in an endless cycle called the Wilson Cycle. The face of the Earth is constantly changing and there is a record of this constant change, dating back almost 4 000 million years, extremely well preserved in the rocks of southern Africa. ❑ Recommended Reading: The Story of Earth and Life: A southern African perspective on a 4.6-billion-year journey. Terence McCarthy and Bruce Rubidge. 2005. Struik. Cape Town.
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The Baberton granites What was happening in the very earliest part of the Earth’s history? How important was plate convergence and subduction in the formation of the Earth’s crust? Geologists from Stellenbosch University have made some important discoveries. This map shows the position of global convergent plate margins (55 000 km long) as jagged lines.
late tectonics is recognised as the central geological process of the modern Earth. However, if, and exactly how, plate tectonics happened during the oldest period of Earth’s history for which a solid rock record remains – the Archaean era (4.0-2.5 billion years ago) – is under dispute.
Subduction The process of subduction is important in Earth’s history because where plates move apart, new oceanic crust is created and where plates converge, continental crust can be created and recycled, while oceanic crust is consumed. Along these convergent plate margins oceanic lithosphere (the crust plus the
top brittle portion of the upper mantle) is subducted to become part of the mantle again. Buoyant island arcs that are part of the subducted plate become accreted to buoyant continental crust and ultimately, as the ocean basin closes, continental crustal blocks collide to build mountain belts. Accretion is a physical process by which solid rock material is added to a tectonic plate or a landmass.
The down-going slab – called the subducting plate – is overidden by the leading edge of the other plate. The slab sinks at an angle of 25-45º to the surface of the Earth. Once the slab reaches a depth of between 80-120 km, the basalt of the oceanic slab is converted to a very dense metamorphic rock, eclogite. As a result, the density of the oceanic lithosphere increases and it is carried into the mantle by virtue of its higher density (slab pull) and by downwelling convective currents within the mantle, as well as a push effect resulting from the fact than the mid-ocean ridges, where oceanic crust is created by plate divergence, stand higher than the surrounding oceanic crust (ridge push). Subduction zones are the regions where the Earth’s lithosphere, oceanic crust, sedimentary layers and some trapped water are recycled into the deep mantle. A geothermal gradient is the rate of increasing temperature in relation to the depth in the Earth’s interior.
These diagrams show how subduction creates island arcs and ocean trenches at continental boundaries.
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Subduction in geological time Without subduction, plate tectonics could not exist. But what was
Effects of subduction Volcanoes Much of Earth’s volcanic activity is found at subduction zones. A volcano is a ruptured area of the Earth’s crust that allows hot magma, volcanic ash and gases to escape from below the surface. Magma is a mixture of molten rock, crystals, and gases. Subduction zones produce volcanic activity because of the effect of water on the melting of rocks. The rocks that form the mantle, oceanic crust and continental crust all melt at much lower temperatures with the addition of water. To use a comparison with processes in the welding or soldering of metals, water can be thought of as a flux that aids the low temperature melting of rocks. The upper layers of subducted oceanic crust, down to at least 3 - 4 km below the surface, contain large amounts of water-bearing minerals (minerals within which water is bound into the crystal structure), such as chlorite. When these minerals are subducted, temperature and pressure increase. This ultimately makes the minerals break down to form less water-rich minerals, and liberates the water to aid the melting of the overlying rocks. This melting creates volcanic activity that is closely associated with subduction zones. For example, the Pacific Ring of Fire is a 40 000 km series of oceanic trenches, volcanic arcs and volcanic belts containing 452 volcanoes and is the source of more than 75% of the world’s active and dormant volcanoes. The Pacific Ring of Fire exists because the Pacific ocean is bounded by a roughly circular pattern of subduction zones that create and sustain this volcanic activity.
The Pacific Ring of Fire.
Image: Wikimedia commons
happening at the very earliest period of the Earth’s history? This period of Earth’s history is puzzling because evidence exists in the rock record which appears to demand a plate tectonic explanation, yet there is a complete lack of some types of the evidence that is typical of modern subduction zones. The South African geological record is rich in exceptionally well-preserved Archaean rocks and these help shed light on this problem. In the Barberton greenstone belt there is evidence that blocks of volcanic and sedimentary rock strata of different ages have been brought together by the lateral motion of plates. In essence, this evidence consists of upper crustal rocks, formed in different places and times, which were brought together along a prominent fault approximately 3.2 billion years ago. Importantly though, two key types of subduction zone evidence from the modern Earth may not exist in the Archaean rock record. The first such evidence is the presence of blueschists, which are metamorphic rocks formed
A tsunami strikes Ao Nang, Thailand on 26 December 2004.
Earthquakes and tsunamis Earthquakes are another common consequence of subduction and are caused by the shock waves generated as the plates slip past one another. Earthquakes start and are propagated in a deep, active seismic area in a subduction zone called the Wadati-Benioff zone, which is named after the seismologists who discovered the zones. Nine out of 10 of the largest earthquakes that occured in the last 100 years were subduction zone events. This includes the 1960 Great Chilean earthquake – which was the largest earthquake ever recorded – the 2004 Indian Ocean earthquake and tsunami and the 2011 Tokyo earthquake and tsunami. When cold oceanic crust is subducted into the mantle it depresses the local geothermal gradient and causes a larger portion of the Earth’s crust to deform in a more brittle way than it would if it was subjected to the hotter temperatures of a normal geothermal gradient. Earthquakes are only triggered by brittle deformation, so subduction zones can create large earthquakes because in these cool zones the domain of brittle deformation extends to great depths and therefore great pressures. If these earthquakes cause rapid deformations of the sea floor, then there is the potential for tsunamis.
Opheiolite from the Odrovician in Gros Morne National Park, Newfoundland.
Image: Wikimedia commons
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Eclogitic nodules Eclogitic nodules are nodules of eclogite, which is a particular type of metamorphic rock. Eclogite forms at pressures greater than those typical of the Earth’s crust and it is an unusually dense rock, and so can drive convection within the solid Earth. Subduction produced eclogite from the oceanic crust. The existence of Archaean eclogite below the old cratons, such as the Kaapvaal craton, is shown by the exposure of these parts of the mantle to the surface by kimberlite magmas that erupt through much of the mantle and the overlying continental crust.
Eclogite sample with garnet (red) and omphacite (greyish-green) as prominent crystals in the rock. The sky-blue crystals are kyanite. Some white quartz is seen too – it was probably once coesite. A few gold-white phengite mica minerals can be seen at the top. Coin of 1 euro (23 mm) for scale. Image: Wikimedia commons
under the very high pressures and low temperatures that exist only in subduction zones. Blueschists are unknown from the Archaean. However, eclogites, which form under pressuretemperature conditions defining similar geothermal gradients to those along which blueschists form, certainly formed during the Archaean. We know this because eclogites which formed more than 3.0 billion years ago are unearthed by kimberlite magmas, which erupt through the lithospheric keels that underlie the old continents. The second piece of evidence relates to opheolites, which are sections of the Earth’s oceanic crust and underlying upper mantle that have been lifted up and exposed above sea level as a result of thrusting of the opheolite onto the
The present-day Kaapvaal craton.
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Image: Wikimedia commons
Eclogite is formed due to the high-pressure metamorphism of igneous rock as it plunges into the mantle in a subduction zone. As the cold oceanic crust moves downwards, it produces a domain of very high pressure, but low temperature, which are the conditions required to stabilise the assemblage of minerals that make up eclogite.
Blueschists Blueschists are another type of rock that is characteristic of subduction zones. These form at lower temperatures and pressures than eclogite, i.e. they form ahead of eclogites as subduction proceeds.
Blueschist, Ile de Groix, France.
continental crust during island arc accretion or during collisions between continents. Some rock successions from Barberton and elsewhere have been proposed as representing opheolites, but these are different in rock structure and chemistry to typical opheolites and their origin remains controversial. As a result, the existence of subduction during the Archaean era is questioned. Kimberlites are a type of volcanic rock, best known for containing diamonds and other gem stones.
The Barberton terrain The Barberton terrain is part of an area called the Kaapvaal craton. The Kaapvaal craton, as well as the Pilbara craton in Western Australia, parts of Canada and west Greenland, represent the few remaining areas of 3.6-3.2 billion-year-old crust on Earth. In the past few years South African geologists, Jean-François Moyen, Gary Stevens and Alex Kisters, have found rocks that record pressures of 1.2-1.5 GPa at temperatures of 600-650 ºC among amphibolites found in the crust of the mid-Archaean Barberton granitoidgreenstone terrain. These high-pressure amphibolites contain garnet and epidote in addition to the hornblende that normally characterises amphibolites.
Image: Wikimedia commons
Amphibolite is a metamorphic rock that is made up mainly of hornblende amphibole. They are typical of a particular set of pressure and temperature conditions – called the amphibolite facies.
The conditions under which these rocks formed suggest geothermal gradients of 12-15 ºC, which are similar to those found in recent subduction zones. In particular, they are similar to the conditions that exist in subduction zones where young oceanic crust is subducted. In the Barberton greenstone belt, the formation of these highpressure amphibolites coincided with the accretion of blocks with different age and stratigraphy (terranes) in the overlying Barberton greenstone belt. Terrane in geology is short for tectonostratigraphic terrane, which is a fragment of crustal material, formed on, or broken off from, one tectonic plate and accreted or ‘sutured’ to crust lying on another plate. This crustal fragment retains its own distinctive geological history, which is different from that of the surrounding areas.
It is these high-pressure and lowtemperature conditions that provide the metamorphic evidence for a cold and strong lithosphere, as well as
subduction-driven tectonic processes during the evolution of the early Earth. The lack of blueschists in the Archean rock record reflects the fact that subducted oceanic crust was hotter, as a consequence of a generally higher geothermal gradient, and possibly also because it was young. Within the Barberton greenstone belt we have crustal rocks that contain evidence that appears to demand that a lateral tectonic process operated on Earth earlier than 3 230 million years. This evidence suggests that both the continental crust and the eclogitic domains in lithospheric keels beneath the continents were produced as a result of subduction zones, which created both the magmas that built the bouyant continental crust and the metamorphic conditions under which the eclogites were stabilised. The resultant old continental crust, underlain by thick lithosphere, has proved to be incredibly long lived, surviving 3.0 billion years of Earth’s turbulent tectonic processes. ❑ Gary Stevens is the SARChI professor in Experimental Petrology, Alex Kisters is Associate Professor of Structural Geology (Stellenbosch University) and J-F Moyen is Associate Professor of Petrology at St Éttiene Université in France. At the time of conducting this research all were based at the Centre for Crustal Petrology at Stellenbosch University.
The Barberton granitoid-greenstone terrain The Barberton Mountain is a well preserved pre-3 billion-year-old granite-greenstone terrain. The greenstone belt is predominantly made up of volcanic, metamorphic and sedimentary rocks that were formed and deposited between 3.55 and 3.2 billion years ago. The granitoid rocks were formed and deposited over a 500 million year time span.
The mountains around the town of Barberton, South Africa, are rich in both history and prehistory. Referred to as the Barberton Greenstone, these mountains derive their name from their greenish hue, and they comprise what may be the world’s best-known greenstone belt. As far back as the 1880s, prospectors were attracted by the region’s gold deposits. Later examinations of the area revealed that the rocks date back some 3.55 billion years. Image: NASA
Quest 8(1) 2012 11
Students from 16 schools took part in the event.
Professor Shaheed Hartley opening the 2011 interschools science competition in Worcester.
Teaching science Science education is struggling to cope with lack of resources and an overcrowded curriculum. But Professor Shaheed Hartley and his team from the Science Learning Centre for Africa at the University of the Western Cape are making a difference. Quest finds out how.
S The 2011 secondary school winners, Noorder Paarl High School with their winning teacher, Mr Steven de Wet. Image: SLCA
The joint primary school winners, Worcester RC (Mr Cecil Felix (left)) and Weltevreden Primary (Mr Anthony Abrahams). Image: SLCA
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cience is essential to any vibrant, growing society and its economy. And to make science part of society, you need scientists – and scientists are born at schools. But every year, analysts decry the poor state of science and mathematics in South African schools – and, in common with many other countries, students turn to subject such as business and commerce, thinking that these are the subjects that will make them employable. The key to encouraging budding scientists is making science fun as a subject. This is exactly what Professor Shaheed Hartley and his team from the Science Learning Centre for Africa (SLCA), University of the Western Cape (UWC) are doing. The SLCA is a support and development centre for teaching and learning science and mathematics education. Under Hartley’s direction, the centre started the science for rural communities project. The aim of the project was to improve the knowledge, teaching and practical and experimental skills of teachers and students in the Cape Winelands Education and Overberg districts. The project is divided into three stages, which start with intensive, interactive workshops for teachers in the participating shools. The next step is building a science club or group at each school to make sure that students can get hands-on experience in planning,
designing and doing experiments. The culmination of all this is an interschool competition, where students pit their skills against students at other schools, which helps them to evaluate their own development and knowledge. The first stage of the project finished in June 2011, the third stage was between June and October 2011 and the competition was hosted on 13 October 2011. Competing for excellence The interschool science competition is not only an opportunity for schools to showcase the success of their new approach to science learning, but one way that the SLCA can judge the success of the project. The 2011 event was held at the NGK Church Hall in Worcester. Selected science clubs at 16 schools were represented by 200 students. Principals, science teachers and parents also came along to enjoy the events of the day. The competition started early, and was opened by Professor Shaheed Hartley, Director of the SLCA. The competition started with the secondary schools, with experiments and exhibitions and was followed by a separate primary school section. The atmosphere of the day was one of fun, but although there was plenty of drama and music along with the science experiments, there was always a scientific explanation at the end.
The results Competition was fierce! The adjudicator panel judged each entry on the level of understanding of the experiment, handling the apparatus, originality, presentation, safety and time allocation – each presentation was allowed no more than 10 minutes. The winner in the secondary school category was Noorder Paarl High School. The primary school category had two winners, Worcester RC and Weltevreden Primary.
Students from De Villiers Primary firing their rocket.
Students from Vergesig Primary creating a string extraction from their elementary plastic bottle. Image: SLCA
An H Venter Primary student showing how he can balance his weight on light bulbs. Image: SLCA
The Science Learning Centre for Africa The UWC Science Learning Centre for Africa (SLCA) of the Faculty of Education is an outreach, support, training and research centre for science and mathematics education. In the Western Cape alone we are supporting science and mathematics
Students from Ashbury Primary connect the vital organs.
Starting fire fountains – Charleston Hill Secondary.
Vusisiwe Secondary’s students heating the compound for an experiment. Image: SLCA
Students from Mullers Rus demonstrating the volcano effect. Image: SLCA
Students from Ashton Secondary preparing to capture oxygen in a gas jar. Image: SLCA
Lighting a fire without matches – students from Noorder Paarl. Image: SLCA
Students from Vergesig shifting the fire.
Students from Suurbraak separating liquids of different viscosities. Image: SLCA
Quest 8(1) 2012 13
educators by providing training in content knowledge, pedagogical skills and practical and experimental skills through workshops, short courses and developmental programmes. The SLCA’s research into the needs of science and mathematics educators allows us to develop relevant outreach projects that address real needs identified by educators at the classroom level. To this end annual projects such as Women in Mathematics, Science Club
development, the National Science Week by the Department of Science and Technology (DST), Avionics as a Career and many others speak to the needs identified by research. The research projects of master and doctoral students of the SLCA are based on ‘live’ projects and feedback into the current challenges faced by the education community. In line with the UWC tradition, the SLCA supports educators and learners from disadvantaged schools in rural and
peri-urban areas and strives to build, in many instances, a first generation of role models in science, engineering and technology. The SLCA serves as a science and mathematics help-desk for educators and learners and assists many schools across the Cape Flats with curriculum challenges that they may encounter. It is our intention to tackle the crisis in science and mathematics education in South Africa and to make a positive difference in the lives of our educators and learners. ❑
Starting a science club Shaheed Hartley explains how to develop a culture of science learning through the science clubs initiative at primary and secondary schools.
ne of the national priorities in education is the effective teaching and learning of science and mathematics at schools. Finding solutions to this crisis are what keeps science and mathematics researchers and practitioners awake. The results in the Senior Certificate examinations and the performance in these disciplines in general point to a systemic challenge that requires novel and innovative solutions. In research conducted by the Science Learning Centre for Africa at the University of the Western Cape (UWC-SLCA) it was found that developing the aptitude and interest of learners in science from an early age and sustaining that interest throughout their school career increases their achievement and performance in science. To this end the UWC-SLCA has established a series of science clubs at both primary and secondary schools and held an annual science competition for participating science clubs. This process has had a good effect on improving the culture of science learning amongst learners of participating schools as well as successful development of a culture of science teaching with committed science teachers. Guidelines for teachers starting science clubs 1 You must be prepared to put in extra time and effort. Commitment and belief in what you do is important. If you’re not sure or confident about projects, experiments, exhibits or science
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activities that learners could do in their science clubs, make contact with the UWC-SLCA (www.uwc. ac.za/slca). We are here to assist. Start with a small group of learners, one class and one grade. Only start with a group of learners that you are comfortable with and that you consider manageable. Work with the science club during break or after school. Make sure that you have a safe and secure environment/classroom where you can work. Avoid working with hazardous compounds in the initial stages of your science club. Safety of everyone concerned is paramount. Once you are confident with doing an experiment, show learners in the science club how to do it. Stress the fact that we learn more from failed experiments than successful ones. Use curriculum experiments and allow selected learners to practise the experiments after school and then conduct/demonstrate it to other learners during the actual teaching period. Read up on small experiments/ exhibits (UWC-SLCA has a booklet that can be made available to you) that you could quickly demonstrate before starting a science lesson. This application has been successfully used by many of the UWC-SLCA participating science teachers as a way to have discipline in their classes. If learners are not quiet
or pay attention no new quick demonstration will occur the next time. You will be amazed how the learners respond. Allow you science club to demonstrate the experiments at assembly. Again this proved to be successful and science teachers are inundated with requests to be part of the science club. You can use different criteria to manage the growth of the science club but remember safety cannot be compromised. UWC-SLCA has a short course on laboratory safety that you might want to attend. Make contact with other science clubs and become part of the community of practice in establishing and expanding the notion that a healthy science culture of learning adds great value to learner performance. Enter science club competitions or exhibitions at a local level to allow your learners (and yourself) to gain confidence in what they do. You can move from there to national competitions. Learners must demonstrate an understanding of the activities that they are involved in and must be able to explain what the science activity is all about. Initially use a designated speaker(s) who can confidently do the necessary explanation. Encourage learners to read up more about the science activities that they are involved in. They can use the library, internet or various science promotion magazines and booklets. Make sure that you plan these activities with the necessary information about the content and safety aspects of the science activity. Good luck and contact us if you need assistance. ❑
Prof Shaheed Hartley, Director, Science Learning Centre for Africa Faculty of Education University of the Western Cape Private Bag X17 Bellville Ph 021 959 2680 Fax 021 959 1285 E-mail: email@example.com Professor Shaheed Hartley is the Director, Science Learning Centre for Africa Faculty of Education. He is passionate about science education and won the National Science and Technology Forum (NSTF) prestigious national award as the 2009 Science Communicator of the Year for the work done in mathematics, science and technology education over the previous five years (2004-2009).
Winner of the first ever Natural Science Olympiad for grades 4 - 9, Masande Shumane of Mandela Junior Secondary School in the Eastern Cape, with one of her many prizes. With her are, from left, Ms Beverley Damonse, Group Executive: Science Advancement of the National Research Foundation, her teacher, Ms C.P. Mququ and Ms Innocentia Buthelezi, CSI Manager of Edcon (Pty) Ltd. Image: SAASTA
Young scientists excel Gauteng was abuzz with young science boffins from across South Africa attending the first ever Natural Science Olympiad Award Ceremony for primary school learners on Friday, 28 January 2012. Over 18 000 learners in grades 4 - 9 from all nine provinces participated in the Olympiad, with only the 59 top achievers selected to attend a two-day long visit to Gauteng and the awards event. The ten best performing learners were from four provinces: the Eastern Cape, Free State, Northern Cape and Mpumalanga. In first position was grade 9 learner Masande Shumane from the Mandela Junior Secondary School in Mhlontlo, Qumbu (Eastern Cape), with a 100% pass. Fellow grade 9 learner Siphamandla Mhlabeni scooped joint second position with a 98% pass, together with eight other learners. When asked about her achievements and future plans the shy Shumane responded that it took hard work and lots of studying to achieve her 100% pass rate. She hopes to become a medical doctor when she finishes school. Her advice to learners who want to participate in the next round is to study hard and stay focused. The rest of the winners sharing second place with a 98% pass rate were: n Four learners from Fichardtpark Primary School in Bloemfontein (Free State) n Two learners from Hoër Volkskool in GraaffReinet (Eastern Cape) n One learner from Laerskool Eureka in Kimberley (Northern Cape) n One learner from Tsandzanani Primary School in
Matsulu (Mpumalanga). Prizes received by the winners included laptops, iPods, digital cameras and book vouchers. Schools with the greatest number of participants and top performing schools received laboratory equipment and vouchers for library books. Top achievers and their educators were treated to two days in Gauteng, visiting the SciBono Discovery Centre, the University of the Witwatersrand Planetarium and the Johannesburg Observatory ahead of the awards ceremony. The competition is managed by SAASTA with CNA as main sponsor. The aim of the Natural Science Olympiad is to identify and nurture talent in Natural Science, Life Science and Accounting; to increase the number of learners who opt for Physical Science, Life Science, Accounting and Mathematics at high schools; and to act as a feeder for SAASTA’s National Science Olympiad for grades 10 - 12, which is now in its 47th year. ‘By running this competition, SAASTA and CNA, part of the Edcon (Pty) Ltd group, aim to contribute towards creating an increase in graduate output in careers where there are shortages of skills,’ says Dr Jabu Nukeri, manager of SAASTA’s Education Unit.
About SAASTA SAASTA is a business unit of the National Research Foundation (NRF) with the mandate to advance public awareness, appreciation and engagement of science, engineering and technology in South Africa. http://www.saasta.ac.za/
Quest 8(1) 2012 15
Not so set in stone – Coelacanth: The 20th century produced a variety of newly discovered species – but few created such a stir as the coelacanth. By Penny Haworth. ‘After the chance discovery of a coelacanth in 1938, trawled off the mouth of the Chalumna River near East London, the coelacanth quickly became the continuing obsessive focus of journalists, crypto-biologists, scientists, eccentric explorers, aquaria and divers.’ <http://www.dinofish.com>
Marjorie Courtenay-Latimer sent this letter with a detailed drawing to JLB Smith to describe her strange discovery. Image: SAIAB
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millions of years previously. It was a full two months before Smith finally got to East London to see the specimen. ‘The first sight hit like a white hot blast!’ After having seen the stuffed fish for himself, he could confirm that it actually was a coelacanth. In naming the fish for science he called it Latimeria chalumnae – this was to pay tribute to Courtenay-Latimer for pursuing her hunch and to note that the fish had been found off the Chalumna River near East London. Scientists had been studying coelacanths since 1839 (Walker, 2002), but only through the fossil remains. The first person to describe a fossil fish was Louis Agassiz, a Swiss naturalist. He had named a fossil fish found in England Coelacanthus granulatus. The genus name Coelacanthus comes from two Greek words meaning ‘hollow’ and ‘spine’ and refers to the hollow spines of the vertebrae that connect to the bones which support the caudal (tail) fin rays; granulatus describes the rough texture of the fish’s spiny scales. During the century that followed, scientists found fossils of many species of coelacanth. The earliest coelacanth species first appeared about 400 million years ago – the most recent appeared to have lived about 70 million years ago and that was where, to all intents and purposes, it seemed that the record ended – coelacanths seemed to have completely disappeared. Smith wrote an article for Nature, a well-known science journal, in which he described Latimeria chalumnae. Popular and scientific interest in the find was fuelled by intense media coverage of the discovery. For Smith, however, the more he studied the specimen, the more questions he found – he knew he needed another specimen to find the answers. However, it was to take another 14 years before a second coelacanth was found. The £100 Fish! In his determination to find more evidence of the existence of coelacanths, Smith posted a reward of £100 in three languages – English, Portuguese and French – for the first two specimens found. Captain Eric Hunt, a trader, distributed leaflets ▲ ▲
The taxidermied specimen which Smith used for his description, shown here with the young curator, Marjorie Courtenay-Latimer, is still on display at the East London Museum. Image: SAIAB
kin to the discovery of prehistoric creatures of the Karoo wandering across the Camdeboo plains, or a real-life ‘Jurassic Park’ dinosaur, the coelacanth (pronounced ‘seel-uh-kanth’) captured the imagination of people across the world. It has been given all manner of nicknames: ‘living fossil’; ‘fossil fish’; ‘dinofish’; ‘the fish that time forgot’; ‘the Christmas fish’; ‘The £100 reward fish’; ‘Old Fourlegs’; ‘a window to the past; a door to the future’. On 22 December 1938 the curator of the East London Museum, Marjorie Courtenay-Latimer, was at the harbour to see if there was anything of interest in the trawl nets. Most of the fish set aside for her by her friend Hendrik Goosen, skipper of the fishing boat, Nerine, that had brought in the catch, were sharks that she already had – but a strange shape lying beneath the other fish attracted her attention. It was an unusual blue colour – but all the more strange, was the shape of its fin – the fin appeared to be attached to the tip of a short lobe that didn’t resemble anything she had seen before. Wrapping the fish in a sack, Courtenay-Latimer needed to get it back to the museum and from there into storage. The best way to preserve the fish until an expert could look at it would be to freeze it, but this was not possible – neither the hospital, nor a nearby butchery, the only places in East London with fridges large enough to hold it, were prepared to store the large, smelly creature. Not having sufficient formalin to preserve the specimen intact, she had no choice but to have the organs removed and the animal stuffed. She made a sketch and, together with a short description, sent it to Professor JLB Smith, an ichthyologist at Rhodes University in Grahamstown. On holiday in Knysna, Smith found the letter among his Christmas mail. He described his reaction when he saw the sketch, ‘…and then a bomb seemed to burst in my brain’. He immediately recognised the fish in the sketch – but at the same time could hardly believe that this could be true. However, the strange, fleshy fins were indeed typical of coelacanths, a group of fish that – according to scientific knowledge at the time – had died out
the fossil that really came to life The find created great excitement in the world media!
Whiteia nielseni from Early Triassic â€“ this beautiful fossil is an adult which was properly identified in 2005 by Dr Eric Anderson, Curator Emeritus at SAIAB, fish systematist and discoverer of a Devonian-age coelacanth at Grahamstown, after it had sat in the Instituteâ€™s display for years. It is only 14 cm long. It lived in subtropical freshwater habitats in central Pangaea, now East Greenland, and comes from the Wordie Creek Formation, Early Triassic (about 240 million years ago). The perfectly preserved fossil was contained in an elongate, grey nodule collected in Greenland given to Prof JLB Smith by Dr Eigen Nielsen during the 1950s. When the nodule was cracked open it split the coelacanth perfectly into a right and left side (counterparts). SAIAB has the right counterpart on display in its foyer and the left one is on display at the East London Museum in the CourtenayLatimer Room. w
These beautifully preserved fossils clearly show distinguishing features of the coelacanth such as the characteristic lobed pectoral and pelvic fins, spiny dorsal and anal fin and a tufted tail and the armour-like plates of the head. Image: Long, John A (1995) pp. 135-135; p.182
Quest 8(1) 2012 17
The South African airforce Dakota that carried Smith to the Comores – Smith stands third from left; Eric Hunt is second from left. Image: SAIAB
The poster advertising the £100 reward.
What did the fossil record tell scientists? Although fossils of Latimeria chalumnae have not been found, the species has not evolved far from the coelacanths that existed millions of years ago – in many ways this makes it a ‘living fossil’. Modern coelacanth specimens have helped palaeontologists confirm many theories based on ancient fossils. Size and physical features The telegram sent by Eric Hunt.
Eric Hunt distributed Smith’s reward leaflets throughout the Comores. The photo shows Eric Hunt and his crew aboard his schooner, the N’duwaro. The ‘reward’ coelacanth is in the box in the lower left corner. Image: SAIAB
‘It was a coelacanth all right; … as I caressed that fish … I was weeping, and was quite without shame. Fourteen of the best years of my life had gone in this search and it was true; it was really true. It had come at last.’ Image: SAIAB
18 Quest 8(1) 2012
throughout the Comores on Smith’s behalf. Fishermen in the Comores had seen coelacanths in their catches from time to time and called it Gombessa, but the flesh was oily and no good to eat, so they didn’t value it and usually threw the remains back into the ocean. On 20 December Hunt was notified that a local fisherman had captured a coelacanth in the Comores. On 23 December 1952 Smith received a telegram from Hunt – HAVE FIVE FEET SPECIMEN COELACANTH TREATED FORMALIN HERE KILLED TWENTIETH ADVISE OR SEND PLANE REPLY HUNT DZAOUDZI COMORES. Smith realised that he had no way to bring the fish to South Africa and made a desperate plea to the then prime minister, Dr D F Malan, who agreed that an air force Dakota aeroplane be made available. Smith later told the story of the rediscovery of the coelacanth in his famous book, Old Fourlegs.
From the fossil record scientists knew that: n Coelacanths could range from very small to as much as 3 m in length. n Coelacanths have a jointed skull: although some other fossil fishes had this feature, it is not found in modern fish. n Coelacanths have lobed fins and an unusual array of other physical features that are unlike modern fishes. Reproduction
The evidence is seemingly contradictory (Walker, 2002) – some fossils showed evidence of eggs; another showed the skeletons of two small coelacanths inside an adult. Answers to these and other questions have been gathered over time since Smith started the first study. For instance, when Marjorie Courtenay-Latimer was forced to remove the organs of Latimeria chalumna, she found that the fish did not have a spine like other fish and when it was cut, it was hollow and a yellow oily liquid seeped out. Smith confirmed this when he started work on the Comores coelacanth. Instead of a backbone, the coelacanth has a notochord – this is a hollow tube filled
coelacanths swim and other questions that remained unaswered were: ‘did they live in groups?’, ‘how did they hunt?’ and did they, as Smith had theorised, use their lobed fins to ‘walk’ on the seabed? Scientists needed to see the animals, alive in their natural habitat. No fossil could provide this kind of evidence. The dawn of a new era in coelacanth research The first people to see coelacanths alive and in the wild, were a team of researchers from the Max Planck Institute in Germany. This team, led by Prof Hans Fricke, designed and built a submersible called Geo that could take two people down to 200 m below the surface of the sea. In January 1987, off the west coast of Grande Comore Island, after days searching for coelacanths, the submersible’s pilot, Dr Jürgen Schauer, and one of Fricke’s students, Olaf Reinicke, spotted a movement in the beam of their submersible lights – this was the first sighting of live coelacanths in their natural habitat. After 1989 there were sightings of coelacanths in Indonesia, Mozambique, and Madagascar. In 1989, Fricke and his team developed a new submersible,
with the same yellow oily liquid. Instead of bone the notochord is made of cartilage. The notochord is a feature that all vertebrates have at some point during the early stages of their development, but before birth the notochord is replaced by bony vertebrae, which make up the backbone. Only very primitive vertebrates retain a notochord all their lives. Studies by French and other scientists on specimens found after 1952 have answered many questions. For example, the question about how coelacanths reproduce was answered in 1975 when scientists dissected a female and found five pups inside – none were inside an egg. This proved that coelacanths, like some sharks and stingrays, are ovoviviparous – each pup begins development inside a membranecovered egg inside the mother’s body. As the pup develops the membrane disappears. The egg’s yolk sac remains attached to the pup’s stomach, supplying the food the pup needs to grow. When the pups have developed sufficiently to survive, the mother gives birth to live young. However, no-one knew how
The Comores coelacanth on display at SAIAB, with the reward poster below it. Image: SAIAB
Coelacanth pup, found inside a female.
A model of a coelacanth pup with the yolk sac attached. Image: SAIAB
Quest 8(1) 2012 19
The submersible Geo, from which the first sighting of a live coelacanth was made. Image: SAIAB
A newspaper article on the plan to track coelacanths in their natural habitat. Image: SAIAB
Coelacanths that was captured on film in their natural habitat in May 2011. Image: SAIAB Suggested reading Anderson, E. Fossil Coelacanth identified. Ichthos. 2005; 76: 2 Long, John A. The Rise of Fishes – 500 million years of evolution. 1995. University of New South Wales Press, Sydney. pp. 135-135; p.182 Smith, JLB. Old Fourlegs: The Story of the Coelacanth. 1956. London. Longman & Co. Walker, Sally M. Fossil Fish Found Alive: Discovering the Coelacanth. 2002. Carolrhoda Books, Inc. Minneapolis Websites Coelacanth: The Fish Out of Time http://www.dinofish.com South Africa enters a new era of deep-sea research http://www.saiab. ac.za/newsitem.php?nid=67
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The ROV that is used by ACEP to track coelacanths. Image: SAIAB
A specimen of a juvenile coelacanth on display at SAIAB.Image: SAIAB
called the Jago, that enabled them to go to even greater depths to search for and film coelacanths living in caves. In 2000, a team of deep divers discovered and filmed coelacanths in caves off Sodwana on the KwaZulu-Natal coast, South Africa – this was the first time scuba divers had seen coelacanths and proof that coelacanths indeed inhabit South African waters. For South African marine science, the discovery of Latimeria chalumnae in 1938 and the sighting and photographing of living coelacanths by the team of deep divers in 2000, were serendipitous events with interesting consequences. Both led to significant research programmes off the African East Coast, the first was started by Prof JLB Smith in the 1940s through to the 1960s. Since then there have been many people involved in seeking out and studying this enigmatic creature. During the 1980s Prof Mike Bruton, then the Director of the JLB Smith Institute of Ichthyology (JLBSI), and Robin Stobbs (JLBSI), continued to conduct coelacanth research, documenting finds in Mozambique and Kenya. In the 1990s Prof Bruton brought Fricke and his team with the Jago to South Africa to explore the coastal waters near the Chalumna River and along the Tsitsikama coast in the hope of finding and filming coelacanths. They were not successful, but since 2001, after the sighting of live coelacanths off Sodwana, research and the promotion of public awareness into coelacanths and the ecosystems that support them has been led by the African Coelacanth Ecosystem Programme (ACEP), a flagship programme of the South African Institute for Aquatic Biodiversity, funded by the Department of Science and Technology. Initiated by Dr Tony Ribbink, then manager of ACEP, in 2002 Fricke and his team were invited to bring the Jago back to South Africa for the official launch of the first phase of ACEP and to film coelacanths off Sodwana Bay. This time they were successful. The coelacanth has become an icon of marine conservation. The mystery posed by the discovery of Latimeria chalumnae was how such an ancient
creature, considered extinct for so many years, and until 1938 only known to science through the fossil record, could have survived virtually unchanged. Now, with new technology available, for the first time South African scientists are in a position to study these remarkable creatures close up. In 2009, into its second phase, the African Coelacanth Ecosystem Programme (ACEP) acquired a remotely operated vehicle (ROV) to increase South Africa’s capacity to undertake observations in areas previously too deep to be monitored by SCUBA (See Quest Vol. 6(4) Dec 2010, pp. 28-30 – Exploring the depths). In May 2011, ACEP conducted an expedition to Sodwana Bay to test the capacity of the new ROV in exploring the deep water environment that is home to the coelacanth. In the spirit of research collaboration which underpins ACEP, more than 16 scientists, ROV pilots and technicians from SAIAB, the South African Environmental Observation Network, Department of Environmental Affairs: Oceans and Coasts, the South African National Biodiversity Institute, Ezemvelo KwaZulu Natal Wildlife, iSimangaliso Wetland Authority and Triton Dive Lodge participated in the expedition. The success of the expedition was captured on film – seven coelacanths were filmed on two separate days of diving off the motor yacht, MY Angra Pequena. (See: http://www.saiab.ac.za/ newsitem.php?nid=67). In addition, valuable habitat surveys, fish and benthic invertebrate fauna were assessed and sampled at depths ranging from 50 m to 120 m. This multi-institutional inter- and trans-disciplinary research expedition proved that South Africa now has the platform and the capacity to conduct deep-sea observational research – we’ve come a long way since MarjorieCourtenay Latimer’s first sighting of a strange blue fish. ❑ All photographs ©SAIAB Penny Haworth is the Manager – Communications and Governance, South African Institute for Aquatic Biodiversity (SAIAB), Grahamstown.
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A voice for young scientists Science, research and engineering exist in every thread of society. Now more than ever, young scientists are finding their voice and stepping up to make science real and relevant for South Africans. By Caradee Wright, Genevieve Langdon and Penny Moore
SAYAS founding members at the launch in September 2011. Image: SAYAS
School learners were asked why they might like to be a scientist, researcher or engineer when they grow up ... n I would like to be an engineer because the world is in need of people in that field. As a woman, it is good to be independent and to be able to earn a comfortable living. This field is challenging, but you get to solve problems (Kirsten, Grade 12). n I want to do research on new animals that are being discovered (Gabriella, Grade 6). n It would be quite cool doing experiments and finding out new things (David, Grade 1). n I love science. I would like to make a new invention (Alyssa, Grade 6). n I am interested in science. I would like to be a scientist who studies the planets (Tayuri, Grade 6). n I want to create a scientific impact on people and the world (Mhlengi, Grade 7).
orn out of a worldwide movement to give young scientists a voice, twenty founding members (see table below) were inaugurated into the newly established South African Young Academy of Science (SAYAS) in September 2011. These young scientists were selected on the basis of their academic excellence and record of service to society. Founding members are committed to serving and meeting the goals of SAYAS for a period of five years. SAYAS founding members come from a range of disciplines including pure sciences, law, medicine, public health, environmental sciences, engineering, and economics but, for many, it’s difficult to identify a single discipline because their work is so multidisciplinary. Science isn’t just about test tubes and white lab coats. It permeates all of life. Science is about trying to understand how the world works – whether it is human behaviour, the economic markets, a nuclear power station or the way the earth moves around the Sun. Science is also about finding solutions to the challenges faced by humankind, such as poverty, starvation, disease, war and environmental damage. Whether it is teaching others, uncovering new knowledge through research or creating something completely new, SAYAS members
SAYAS founding members and their disciplines Fulufhelo Nelwamondo Bronwyn Myers Penny Moore Alta Schutte Christine Lochner Genevieve Langdon Jeff Murugan Shadreck Chirikure Caradee Wright Voster Muchenje Jerome Singh Andrew McKechnie Bernard Slippers De Wet Swanepoel Mathieu Rouget Rangan Gupta Mpfariseni Budeli Aldo Stroebel Andrea Fuller Yahya Choonara
Electrical engineering Addictions, psychology, mental health Virology Cardiovascular physiology Anxiety, stress disorders, obsessive-compulsive spectrum disorders Dynamic response of structures and materials, blast loading String theory and quantum gravity Archaeology, iron age, heritage studies, archaeometallurgy Environmental health, skin cancer prevention Animal science, meat science Law, ethics, health policy, governance Zoology Microbiology, plant pathology Diagnostic audiology Ecology, biodiversity conservation, spatial planning, geographic information systems Macro-economics, monetary economics, time series econometrics Law Rural development, sustainable agriculture Physiology, thermal physiology, eco-physiology Pharmaceutics
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are passionate about finding ways to integrate their work into real life and many feel strongly that their research is driven by a desire to improve society. This ranges from developing new drugs or working towards vaccines, to protecting animals from harmful diseases, finding better ways to grow crops or preventing climate-related cancers. Although many of the SAYAS members have studied and worked outside South Africa, they believe that their work, and that of the many excellent young scientists in institutes across South Africa, can contribute to issues that are specific to developing countries – the role and responsibility of South African scientists in tackling South African and African problems is crucial. Now that SAYAS founding members have come together to be a young voice for science in South Africa, they will go beyond their individual specialities and contribute to discussions and debates. SAYAS has four immediate strategic objectives: n To promote science as career of choice among young people n To contribute actively to science policy n To translate science for society and promote science awareness n To encourage the development of novel and innovative approaches to problems of national and international importance. Promoting science and social science as a career of choice among young people Pursuing a career in science or social science does not necessarily mean that you will be a university professor. There are many different sectors in the job market where scientists play a crucial role, such as in government, medicine, education, industry, consulting, entrepreneurship, and more. Those who choose a more academic route have the opportunity to combine their passion for research with teaching the next generation of young scientists. However, for school learners interested in choosing a future in the sciences, there are often no clear role models who can engage with learners, answer their questions and address their concerns. One of the priorities of SAYAS founding members is therefore to connect with school learners
in South Africa
Caradee and Genevieve at work.
– to better understand your joys and challenges, and to foster a passion for science and the world around us. Being a young scientist at school can be tough. SAYAS asked school learners to describe some of the challenges. Sometimes ‘a person is regarded as being a nerd if you are good at science’ (Sarah, Grade 7) and at a time in life when your peers’ opinion counts most, this can be difficult to deal with. On the other hand, science is often perceived as too difficult – ‘science is a totally new way of thinking’ (Kirsten, Grade 12). Often, how learners perceive science is far from the truth. For Prof Alta Schutte (North West University), one thing she wished she had known about science when she was at school was ‘that science does not always equal funkycoloured bubbling bottles in a chemistry lab’. For example, environmental scientists spend much of their time outdoors in nature, archaeologists and palaeontologists rely on fieldwork, and social scientists spend much time interacting directly with people to improve their lives. Young scientists from around the world will descend on South Africa in May 2012 From the 20 to 24 May 2012 members of the Global Young Academy (GYA) will visit South Africa for their annual general meeting, organised in collaboration with SAYAS. The GYA is an international group of around 170 young scientists from 54 countries and five continents. The GYA aims to empower and mobilise young scientists to address issues of importance to early career scientists. The GYA general assembly theme is ‘Sustainability – lesson on the road between Rio and Rio+20’. In addition to tacking this broad subject, GYA and SAYAS members will also jointly participate in outreach activities aimed
at school learners, and GYA member will visit local academic institutions to foster research partnerships and identify possibilities for collaboration. Do you have ideas about how SAYAS can promote science in South Africa? SAYAS founding members are on the lookout for good ideas about how we can promote science in South Africa and be a voice for young scientists in our society. If you have ideas on how we can do this then please contact SAYAS (Email: Dorothy Mutheu, firstname.lastname@example.org), no matter how young or old you might be. Later this year there will be a call for ten additional members to join SAYAS. Criteria include being in possession of a PhD or equivalent degree in any field of scientific enquiry, where science is defined broadly as encompassing natural sciences, social sciences and humanities, medical sciences and engineering; evidence of scientific excellence through a proven publications record, and receipt of honours and awards; evidence of activities demonstrating service to society; and be under the age of 40 years and/or within seven years from receipt of a PhD at the time of nomination. If you would like to apply, watch out for the call through your institution –SAYAS will welcome your application. ❑
SAYAS founding members say that their science or career is cool because… ... like a detective, I get to figure out why people act the way they do, with the added bonus that when their behaviour is not working for them, I help figure out how to change it (Prof Bronwyn Meyers, Medical Research Council/University of Cape Town). ... I get to blow things up! (Prof Genevieve Langdon, University of Cape Town). … Occasionally, just occasionally, there is a ‘eureka’ moment, where I see, or understand something for the first time. And that moment is completely addictive! (Dr Penny Moore, National Institute for Communicable Diseases/University of the Witwatersrand). ... it allows me to combine natural and socioeconomic scientific principles to provide nutritious, functional and safe food for people (Prof Voster Muchenje, University of Fort Hare). ... it connects people – babies with mothers, grandparents with children, friend with friend – through communication. The sense of hearing connects us (Prof De Wet Swanepoel, University of Pretoria). ... my days are filled with variety and interactions with people – students and academics – who usually are much smarter than me and always keen to share knowledge. My main research aim is to understand how animals will cope with climate change and I love the satisfaction of discovering important new insights, through undertaking innovative field work in southern Africa and other parts of the world (Prof Andrea Fuller, University of the Witwatersrand). ... I get to meet incredible people, see new places, explore unanswered questions, but also see my work published and read by other people – now, that’s rewarding! (Dr Caradee Wright, CSIR).
SAYAS members answered school learners’ questions Question: What made science so appealing to you, and why did you decide to make it your career? (Kirsten, Grade 12) Answer: My career in science has given me opportunities to generate new knowledge, contribute to conservation and environmental issues, and train students who are passionate about science and conservation. At the same time, it has been a whole lot of fun, and has allowed me to travel to some of the most amazing places on Earth (Prof Andrew McKechnie, University of Pretoria). Question: What inspired you to be an engineer when you were little and who guided you? (Meagan, Grade 7) Answer: I loved science and maths as a child and was fascinated by how things work. I was inspired to do engineering by the way they use science and maths to make a difference in the real world. I took advice from my school careers advisor, my university lecturers and read a lot of websites to find out more information (Prof Genevieve Langdon, University of Cape Town).
Visit the SAYAS web space: http://www.assaf.org.za/ sayas-south-african-young-academy-of-sciences/ Caradee Wright is a Senior Researcher at the CSIR Climate Studies Modelling and Environmental Health Research Group and co-chair of SAYAS. Genevieve Langdon is an Associate Professor in the Department of Mechanical Engineering at the University of Cape Town and a founding member of SAYAS. Penny Moore is a Virologist at the National Institute for Communicable Diseases and an executive committee member of SAYAS.
SAYAS founding members with the Minister of Science and Technology, Naledi Pandor. Image: DST
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Terrestrial predators, mammal-like An international team of palaeontologists from Brazil, South Africa and Turkey have recently described the oldest land-living predator known from South America in the prestigious journal Proceedings of the National Academy of Sciences. Quest explains why this find is so important.
Pangaea â€“ showing the position of the modern continents. Image: Wikimedia Commons
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he Karoo Basin of South Africa has some of the richest fossil beds in the world and is home to an important group of fossil vertebrates, the therapsids. Therapsids are commonly called mammal-like reptiles because the group includes the direct ancestors of mammals â€“ including the primates such as ourselves. The importance of the fossil beds in the Karoo Basin is that they are key to our knowledge of how the animals of the middle Permian period (more than 260 million years ago) evolved and were distributed. This is of particular importance to us as humans as this is the period when mammal evolution took a huge leap. Before exploring this era of evolutionary time we need to understand something about the Earth as it was then.
Pangaea The middle Permian period is the name used to describe the time between about 270 - 260 million years ago (Ma). This is also called the Guadalupian period. At this time the arrangement of the continents of the Earth looked very different from today. This large mass of land was called Pangaea and was a continuous mass of land, which allowed animals (and plants) to spread easily from area to area. However, there were shallow seas in these land masses and what is now known as the Karoo Basin was covered with a shallow sea, called the Ecca Sea. Over time, the Ecca Sea gradually filled up with sediments that were deposited in deltas along its shores. By the end of the middle Permian, the Karoo Basin became a vast lowland region, surrounded by what are now called the Cape Fold Mountains. This is the region
Q Palaeontology Pampaphoneus hunting a pareiasaur. Image: Voltaire Neto
reptiles and the pampas
relationships of these fossils also give us a very good idea of how the continents of this ancient land mass were arranged. Where the therapsids fit in During the middle Permian, a group of reptile-like creatures called ‘pelycosaurs’ were almost completely replaced by the more advanced therapsids. The ‘pelycosaurs’ survived into the late Permian. They have direct links with mammals,
Above left and above: An artist’s impression of Anteosaurus magnificus (South Africa) and the skeleton of Titanophoneus potens (Russia). Image: Wikimedia Commons
where there is an abundance of fossil vertebrates and the most abundant are fossils of therapsids. Because of the way in which the land masses were formed, there are remarkably few rock deposits around the world that date to this time. The other known middle Permian deposits are the Russian Platform, the Chinese Xidagou Formation in Gansu Province and the Ruhuhu Formation in Tanzania. This means that it is difficult for palaeontologists to get an accurate idea of how the evolution of important groups of animals, such as the mammals, occurred during this time, because movement of these evolutionary lines would have played a major role in evolutionary outcomes. The distribution and
Ophiacomorph – a ‘pelycosaur’.
Image: Wikimedia Commons
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The fossil skull and an artist’s reconstruction of Pampaphoneus biccai. Image: Juan Cisneros
best known are the huge Anteosaurus magnificus from South Africa and Titanophoneus potens from Russia.
The team who led the fossil find in Brazil.
Image: Wits University
showing features such as differentiated teeth and a hard palate. However, it is the therapsids that are the direct ancestors of modern mammals. As the therapsids took over from the ‘pelycosaurs’, the food webs of the terrestrial vertebrates were modified and one of the main actors in this ecological change were the dinocephalian therapsids – these were the largest land-living animals of the time and included carnivores and herbivores. The carnivorous forms were the Anteosaurids, of which the Therapsids as ancestors of mammals Early therapsids found in the Karoo Basin, such as Thrinaxodon have a mixture of ancestral ‘reptile-like’ and more advanced ‘mammal-like’ features: n Strongly bowed cheek bones show that they had powerful jaw muscles that were used for chewing food. n Their teeth have specialised incisors, large canines (sabre teeth) and multi-cusped teeth at the back of the jaw – unlike the peg-like teeth of reptiles. n The roof of the mouth is made up of a bony palate, which separates the breathing and eating passages, which allows mammals to eat and breathe at the same time. n The rib cage is short, which suggests that they had a diaphragm as in mammals, which had a role in breathing. Reptiles, in contrast, have a rib cage all the way down their bodies. n The limbs are pulled in under the body, which suggests that they were semi-erect and the shoulder and hip girdles are lightly built, for mobility.
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The Permian therapsids So why is the recent find of an Anteosaurid dinocephalian in South America so important? The new species found in South America is called Pampaphoneus biccai. The genus name means ‘pampas killer’ (pampas are the flatlands of southern Brazil, Uruguay and Argentina). The species name is in honour of José Bicca, landlord of the farm where the fossil site is located. Pampaphoneus is very closely related to a South Africa dinocephalian known as Australosyodon which was discovered on a farm close to Prince Albert Road in the southern Karoo in the late 1980s by a team led by South African palaeontologist Bruce Rubige, Director of the Bernard Price Institute (BPI) for Palaeontological Research at Wits. The new fossil, which comprises a complete and wellpreserved skull measuring 35 cm in length, was discovered in 2008 on a farm in the pampas region of Rio Grande do Sul, in southern Brazil. The find is important for two reasons: first, it is the oldest land-living flesh-eating animal yet discovered in South America and is about 265 million years old. Second, it provides new evidence of the arrangement of the continents in the supercontinent of Pangeae in the Middle Permian Period. Comparable fossils have also been discovered in Russia and China. The new
Brazilian discovery now demonstrates that a similar diverse middle Permian therapsid fauna is present in South America as well. ‘Ten years ago we only had a poor idea of terrestrial vertebrate faunas from South America. New findings like this allow us not only to know with more detail how the Permian fauna from South America was but also recognise that this Brazilian fauna, together with those from South Africa, China and Russia, have the oldest mammal-like therapsids in the world,’ says Abdala, senior researcher at the BPI for Palaeontological Research. The new species, which is very closely related to the carnivorous dinocephalians already known from Russia and South Africa, indicates the global distribution of terrestrial faunas in the super-continent of Pangaea that were already present in the Middle Permian. This shows that land-living vertebrate animals were able to move over land from Gondwana (south Pangaea) to Laurasia (north Pangaea) more than 260 million years ago. ❑
An artist’s impression of Australosyodon – found in the Karoo in the 1980s. Image: Wikimedia Commons
Q News Dinosaur nursery A Canadian palaeontologist at the University of Toronto, Professor Robert Reisz, led a team of scientists who have found the oldest known dinosaur nesting site in the Golden Gate Highlands National Park. The study reveals clutches of eggs – many with embryos – as well as tiny dinosaur footprints, providing the oldest known evidence that the hatchlings remained at the nesting site long enough to at least double in size. Bernard Price Institute (BPI) Director, Professor Bruce Rubidge says, ‘This research project, which has been ongoing since 2005, continues to produce groundbreaking results and excavations continue. First it was the oldest dinosaur eggs and embryos, now it is the oldest evidence of dinosaur nesting behaviour’. The authors say the newly unearthed dinosaur nesting ground is more than 100 million years older than previously known nesting sites. At least ten nests have been discovered at several levels at this site, each with up to 34 round eggs in tightly clustered clutches. The distribution of the nests in the sediments indicates that these early dinosaurs returned repeatedly (nesting site fidelity) to this site, and probably assembled in groups (colonial nesting) to lay their eggs, the oldest known evidence of such behaviour in the fossil record. The large size of the mother (six metres in length), the small size of the eggs (about six to seven centimetres in diameter), and the highly organised nature of the nest suggests that the mother may have arranged them carefully after she laid them. ‘The eggs, embryos and nests come from the rocks of a nearly vertical road cut only 25 metres long,’ says Reisz. ‘Even so, we found ten nests, suggesting that there are a lot more nests in the cliff, still covered by tons of rock. We predict that many more nests will be eroded out in time, as natural weathering processes continue.’ The fossils were found in sedimentary rocks from the Early Jurassic Period
in rthe Golden Gate Highlands National Park in South Africa. This site has previously yielded the oldest known embryos belonging to Massospondylus, a relative of the giant, long-necked sauropods of the Jurassic and Cretaceous periods. ‘Even though the fossil record of dinosaurs is extensive, we actually have very little fossil information about their reproductive biology, particularly for early dinosaurs,’ says David Evans, a curator of Vertebrate Palaeontology at the Royal Ontario Museum. ‘This amazing series of 190-million year old nests gives us the first detailed look at dinosaur reproduction early in their evolutionary history, and documents the antiquity of nesting strategies that are only known much later in the dinosaur record,’ says Evans. The research paper, called Oldest known dinosaurian nesting site and reproductive biology of the Early Jurassic sauropodomorph Massospondylus, was published in Proceedings of the National Academy of Sciences international journal. Dr Adam Yates of the BPI for Palaeontological Research at Wits co-authored the study with Drs Hans-Dieter Sues (Smithsonian Institute, USA) and Eric Roberts (James Cook University).
The dinosaur nest containing eggs.
Three eggs, containing embryos.
Image: Wits University
Image: Wits University
Situated in the academic and historic heart of the Eastern Cape, St Andrew’s College, the Diocesan School for Girls (DSG) and St Andrew’s Preparatory School in Grahamstown offer a kaleidoscope of subjects, activites and outdoor education. Outstanding Maths and Science teaching is complemented by a variety of Matric subjects including Drama, Ballet, Music and Design (architecture, fashion or jewellery). Boys and girls at St Andrew’s College and DSG share campuses from Grade 8 and all lessons from Grade 10. A fossilised baby dinosaur footprint.
Image: Wits University
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Quest 8(1) 2012 27
NASA’s Hubble Space Telescope snapped this image of the planetary nebula catalogued as NGC 6302, but more popularly called the Bug Nebula or the Butterfly Nebula.
In the darkest deepest recesses of our universe lurk extremely massive compact objects. Marisa Geyer and Jeandrew Brink explore the nature of spacetime around these exotic structures by observing objects in orbit around them.
Of butterflies and bumpy black holes
received an unusual gift. I found a box tied with a red ribbon waiting on my desk. Interesting – it wasn’t my birthday. I dropped my bags and opened the box uncovering two pink cheeked apples attached at the stem. It turns out that these apples are directly related to the first object whose carefully studied trajectory led to the formulation of the concept of gravitation.
An extract from William Stukeley’s manuscript which would later become the biography Memoirs of Sir Isaac Newton’s life. Image:The Royal Society
The two Newtonian apples gifted to me by my roommate, Cato Bekker. Image: Jane Geyer
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From Newton to Einstein Legend has it that Sir Isaac Newton was sitting under an apple tree, when ‘boink’ an apple hit his head. The impact jolted him into the realisation that the same force that brought the apple crashing onto his head also keeps the moon falling towards the Earth and the Earth towards the Sun: gravity. The legend isn’t too far from the documented truth. In the manuscripts of William Stukeley, an archaeologist and one of Newton’s first biographers, he records a conversation that took place with Newton in 1726: ‘After dinner, the weather being warm, we went into the garden and drank thea, under the shade of some
apple trees...he told me, he was just in the same situation, as when formerly, the notion of gravitation came into his mind. It was occasion’d by the fall of an apple, as he sat in contemplative mood. Why should that apple always descend perpendicularly to the ground, thought he to himself.’ So important was this notion of gravity that in commemoration of its discovery, people have carefully cultivated the descendants of the original apple tree. It turns out that my roommate’s dad has a certified Newtonian apple tree on their farm in Franschhoek. When the tree bore its first two apples it made a perfect gift for her physics enthusiast friend. Since that first Newtonian apple fell, our understanding of gravity has been continuously refined. Newtonian gravity successfully predicts the elliptical motion of most of the solar system planets and for the most part suffices to help NASA put satellites and shuttles up in space. Newtonian gravity, however, cannot account for the way in which the planet Mercury orbits the Sun, or the fact that the Sun deflects the light from distant stars that pass it during an eclipse. Describing
these phenomena needed more finesse. In 1915 Einstein suggested to the Prussian Academy of Science that instead of thinking of gravity as a force, we should categorise it in terms of geometry. Einstein’s idea was that the orbit of the Earth around the Sun can be explained by joining the threedimensional world that we observe (space) with a fourth familiar coordinate – time. In so doing he created a four-dimensional union called spacetime. He proposed that the presence of a mass like the Sun curves the geometry of spacetime around it and that the Earth then moves in a straight path on the curved background to go around the Sun. These straight paths are called geodesics. An easy way to imagine this is to think of space and time forming an elastic mesh or trampoline. Wherever you place a heavy planet or star, you cause a deep dent in the fabric of spacetime. An extremely massive object like a black hole, creates an infinitely deep dent which is called a singularity. Einstein formulated his new theory of gravity mathematically in terms of the Einstein field equations that govern the geometry of spacetime. These equations relate the curvature of spacetime to its source: the presence of matter that has mass and energy. From the field equations you can calculate how much spacetime is being warped because of the presence of a planet or star or black hole.
that when a massive star had burned up all its nuclear fuel, there would be no resistance to the gravitational pull at the core and the star would collapse under its own weight, becoming smaller and denser. It would keep on collapsing until it curved spacetime strongly enough to form a black hole. Typical stellar black holes have a mass more than ten times that of the Sun, squashed into a sphere with a radius 200 times smaller than the Earth’s. Supermassive black holes can weigh up to a billion times more than the Sun. Today it is commonly accepted that most galaxies have a supermassive black hole at their centre, that helps gravitationally to bind the galaxy’s contents together. The supermassive black hole at the centre of our galaxy is dubbed, Sagittarius A-star or Sgr A* for short. Many theoretical physicists believe black holes are very simple structures. The mathematical theorems, known as the No-hair theorems, suggest that, irrespective of their origin before collapse, any resulting black hole can be fully described by just three numbers: its mass, angular momentum and its electric charge. All other information about its origin is lost. A black hole is thus predicted to have no lumps, bumps or ‘hairs’. They are bald, boring and spheroidal in shape. Any mathematical theorem is just as strong as its assumptions. The assumptions that go into the No-hair theorems are the ideas of cosmic censorship, causality and that Einstein’s field equations are valid in all regions
Spacetime depicted as a two dimensional trampoline where the Sun creates a deep dent around which the Earth orbits. This shows how gravity can be thought of as geometry.
A computer-generated image by NASA showing how the deeply dented spacetime around a black hole causes even light to bend.
of spacetime. Cosmic censorship is the idea that the singularities of spacetimes are hidden from view and that no light can escape from these strongly curved regions of space to tell us something about them. Causality is the statement that nothing can travel through time or interfere with its own past. That means the order of an event and its effect is never reversed. These assumptions seem innocuous enough. The scientific
Black holes: Bald or bumpy? Shortly after Einstein wrote down his equations, Karl Schwarzschild was working in the trenches on the Russian front during World War I experiencing heavy gunfire. In these sub-optimal conditions he found a particularly interesting exact solution to the field equations. The Schwarzschild solution, as it became known, described a gravitational field so strong (or a spacetime dent so deep), that not even light would be able to escape from it. He was mathematically describing what would later be called a black hole, when no one yet knew how such an immensely dense object would come into existence. In 1939 two American physicists, Oppenheimer and Snyder, showed
A three-dimensional approximation of spacetime around Earth. In the inset gravitational waves come off as a result of orbital motion on the spacetime fabric. Images: with credit to WGBH Boston, NASA and networkologies.
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First experimental verification for GWs – The Hulse-Taylor Pulsar or PSR B1913+16 n A pulsar is a highly magnetised neutron star that emits two beams of radiation in opposite directions. These sweep around the sky as the star rotates. We detect this radiation using radio telescopes n If the pulsar is in orbit around another neutron star, the gravitational waves (GWs) carry away energy causing the orbits to shrink. n By watching the pulsar beam we observe the resulting increase in orbital frequency. n Russell Hulse and Joseph Taylor of Princeton University, analysed the first system of this type, which now bears their name. For this work they were awarded the Nobel Prize in Physics in 1993.
Hunting gravitational waves. The LIGO Livingston Observatory makes incredibly precise measurements of the distance between two pairs of mirrors. The light enters through a beam splitter at the corner of the L-shaped interferometer, which divides the light between the two 4 km lengthed arms. Light repeatedly bounces back and forth between the two suspended mirrors in each arm. If the distances between the arms are unchanged, the exiting light interferes destructively and there is no signal. If the distances do change, due to a gravitational wave passing through, the waves will not interfere destructively as before, and the photo detector will measure the escaping light. This light is then direct evidence of the gravitational wave’s wake. Images: LIGO
question however is – are they right? Henceforth we shall use the term ‘bumpy black holes’ to describe possible black hole like structures that violate the No-hair theorems. Today scientists are actively seeking ways to make measurements that probe the highly warped regions of spacetime and to hunt for the existence of bumpy black holes. If discovered, these objects would herald the fact that something was amiss with the No-hair theorems, just as careful measurement of Mercury’s orbit told us that Newtonian gravity was not the final word on gravitation. Gravitational waves A second prediction of Einstein’s theory of general relativity (GR) is the existence of gravitational waves
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the foreseeable future these detectors should provide us with a whole new way of looking at the universe.
that travel at the speed of light. In the same way that dropping a rock in a pond causes ripples, or an electron moving in an antenna sends out radio waves, masses moving around in the presence of a gravitational field send out gravitational waves. These waves carry energy away from any two orbiting objects (a binary) and cause the objects to spiral in toward each other. We know these waves exist because we observe the orbital decay of very dense objects such as the neutron stars in the Hulse-Taylor pulsar system. The Earth also gives off gravitational waves as it orbits the Sun. The effect however is immeasurably small; our orbit shrinks by less than the diameter of a proton per day. If we could detect the gravitational waves coming from binary inspirals directly and tune into them much as a car radio picks up the signal of a radio broadcast, these waves could tell us a great deal about the spacetimemesh they originated from. In an attempt to directly measure disturbances caused by a passing gravitational wave, a massive collaboration of scientists have built the Laser Interferometer GravitationalWave Observatory (LIGO). LIGO consists of lasers arranged in an interferometer to make precision measurements of two pairs of mirrors hanging 4 km apart in an L-shape. The disturbances they want to measure are expected to be about the size of one-hundred-millionth the diameter of a hydrogen atom and so pose a formidable experimental challenge. There are three interferometers in the United States, and other detectors in Germany, Japan, Italy, and more are planned in India and possibly China. Scientists are currently trying to lower the noise levels in LIGO to reach the sensitivities required. In
Checking out black holes Richard Gott, an astrophysicist at Princeton University, famous for his interest in time-travel noted: ‘A black hole is a hotel you check in at, but you never check out.’ His observation highlights an obvious difficulty in exploring the structure of a black hole. No messenger, not even a photon, can escape a black hole to reveal whether it is bumpy or bald. Any attempt at a direct measurement leaves the observer forever captured within the black hole – a truly crushing experience. The least dangerous way of checking out the nature of a large black hole is to ‘watch’ something else check in. Nature provides many such unfortunate guests to the black hole at the centre of our galaxy, in the form of neutron stars and white dwarfs in its vicinity. These objects are relatively light when compared to the mass of Sgr A*. As a result they alter the spacetime dent Sgr A* causes in a negligible way. We call the trajectory these stars follow as they approach the large black hole an extreme mass ratio inspiral or EMRI event. We can ‘watch’ the progress of the EMRI trajectory by recording either the gravitational or electromagnetic waves emitted by the object as it spirals in. Typically these objects will spend years and complete more than 100 000 orbits around the central black hole before finally disappearing from view as they permanently check in. By capturing and analysing this data we hope to make sensible deductions about the nature of the spacetime the object is moving in and possibly also infer some of the structure of the large black hole causing the dent. Chaotic butterflies vs ordered buoys Before we proceed to decide whether our strategy for checking out a black hole is an effective one, consider the following analogy. Imagine you find yourself walking in the veld on a dark moonless night. You see nothing, but hear a river flowing. You don’t want to fall into the river and decide to attempt to map out the shape of its bank. You
South Africa is bidding against Australia for a powerful new radio telescope. If successful the Northern Cape would host a radio telescope 50 times more sensitive than any existing telescope. Radio telescopes will not only be set up in South Africa but also in eight different African countries – greatly increasing the collecting area of the telescope. Image: Artist impression by SKA
attach a small blinking LED light to a cork and drop it into the river. As the little blinking light moves downstream you record its trajectory. If the river is calm and has laminar flow, the moving cork will give you a good indication of the course of the river and thus of the river bank. However, if the river is turbulent and unpredictable, the cork will be violently tossed in the torrent, exhibit erratic motion and not trace out the shape of the bank of the river. From this outcome of your experiment you might infer a totally incorrect shape of the river. If the river is turbulent you need to observe many corks’ motion to deduce anything concrete. Studying an EMRI event involves exactly the same risk. Suppose we assume a priori that the neutron star is spiraling into a ‘bald’ black hole that obeys the No-hair theorems such as the Schwarzschild solution. This case would correspond to the cork on a river with laminar flow – the EMRI orbit will behave in an ordered predictable way, well understood by physicists. If however the neutron star is in orbit around a bumpy black hole our understanding becomes more murky. Three possibilities exist – firstly its motion could be ordered, or as mathematicians say integrable, just like the motion around the Schwarzschild black hole. In this case we could get an idea of the nature of the bumpy black hole by watching the orbit. The second possibility is that the orbit is chaotic, just like the cork in the turbulent river. In this case the neutron star’s irregular motion does not necessarily reveal information about the structure of the central black hole. The third possibility is a mixture of the first two – regions of order coexisting with regions of chaos. We are currently trying to determine which scenario best describes the orbits around bumpy black holes by studying exact solutions to the Einstein field equations. We are also
Extreme mass ratio Insprials
? A low mass probe slowly spirals in around a large compact object, such as a black hole – bumpy or bald.
As the probe spirals in it samples the geodesic structure and broadcasts the information as gravitational waves and electromagnetic radiation.
Gravitational waves will be measured by advanced LIGO and radio waves received by the Square Kilometer Array (SKA).
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that a distant butterfly flapping its wings several weeks before could be a deciding factor as to whether or not a hurricane formed! We have yet to establish how much the butterfly effect that is present in bumpy black holes limits the detail to which their structure can be determined from observations. Large regions of order in bumpy black hole spacetimes, however, do suggest that it is likely that their nature will be more predictable than the weather.
The authors, Jeandrew Brink (top) and Marisa Geyer (centre) on a recent visit to the California Institute of Technology (Caltech), in Los Angeles. We are posing in front of the Cahill Centre for Astrophysics with collaborators Fan Zhang (left) and Aaron Zimmerman (right). Caltech is a hotbed of gravitational wave research, hosting the scientific research groups of Kip Thorne, LIGO’s co-founder, as well as large groups working on LIGO data analysis, experimental research and development, source modelling, and numerical relativity. Image: Michele Vallisneri
trying to determine exactly what we will observe with our detectors and how we will use that observation to quantify the nature of the black hole. Some of the spacetimes we have looked at indicate that the third option is likely. In highly curved regions of spacetime around bumpy black holes both regular and chaotic orbits are found. This is almost like having calm and turbulent flow regions intertwined in the same river. The chaotic regions of spacetime pose an experimental challenge. The outcomes of any experiment in the chaotic regime is intensely sensitive to where the neutron star is when you start measuring. If you change the initial conditions only slightly the experimental outcome is vastly different. Experiments are thus not repeatable in the traditional sense. The idea that a small change in initial conditions can result in huge changes in the later state was termed the butterfly effect by Edward Lorenz. He first studied the phenomenon in the context of predicting extreme weather patterns like a hurricane. To his surprise the equations indicated
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Measurements – unusual gifts Science is driven by precision measurements, conceptual advances and good questions. Within the next 20 years two powerful new observational tools will be placed at our disposal, namely the Square Kilometer Array (SKA) and the advanced LIGO observatory. The SKA is a radio telescope with 50 times the sensitivity and 10 000 times the survey speed of current stateof-the-art telescopes. It is a fantastic machine and one of its science goals is to observe a neutron star orbiting a black hole. When advanced LIGO reaches design sensitivity, it is expected that several inspiral events will be recorded per year. Possibly the most powerful diagnostic tool for observing the nature of black holes is to have both detectors look at the same EMRI event. This would give two completely different eye witness accounts of how a neutron star checks into a black hole and eliminate much of the uncertainty inherent in any experimental measurement process. Einstein said, ‘No amount of experimentation can ever prove me right; a single experiment can prove me wrong’. In four year’s time Einstein’s theory of general relativity (GR) will celebrate its centennial anniversary. In the last 100 years its predictions have been consistent with all experiments conducted. Einstein once gave sage advice to physicists young and old when he said, ‘A man should look for what is, and not for what he thinks should be’. Sometimes, however, the conceptual framework within which you work or look determines what mysteries you uncover. So to his suggestion I would respond: ‘Professor Einstein we took your theory, looked for what it suggested there could be and found the world that is, to be far richer than we thought it
would be’. The conceptual framework of GR suggests the correct orbit for the planet Mercury and predicts the bending of light by a gravitational field. GR predicts the gravitational redshift of light travelling in a strong gravitational field. It predicts the gravitational time delay, a concept essential for correctly determining positions on Earth using the Global Positioning System. GR predicts the existence of gravitational waves. It predicts the existence of black holes. GR works so well that the measurements to test it further have become increasingly precise and the calculations difficult. But, tested further, it will be to determine to what extent it captures the world that is. When the results from the SKA and LIGO become available, I will again have a present waiting on my desk. It will be tied up with long equations, uncertainty, discussions and debate. I will drop my bags and pry open that theoretical box, squinting I will look inside. With bated breath I will attempt to behold are black holes bumpy or bald? ❑ Marisa Geyer (firstname.lastname@example.org) is in her final year of Master’s study at Stellenbosch University. After completing her honours in nuclear physics, she left the field for a year to study journalism. She still hopes to do science writing on the side, making the world of science more interesting and accessible to the general public. Since 2011 she has become a scholarship holder of the Square Kilometer Array and has met up with Dr Jeandrew Brink, with whom she is currently researching extreme mass ratio inspirals. Dr Jeandrew Brink (email@example.com) is a researcher at the National Institute for Theoretical Physics in Stellenbosch. She loves exploring various aspects of numerical and analytic relativity, gravitational waves, astrophysics, dynamical systems and fluid dynamics. Jeandrew was born in Bloemfontein and obtained a MSc in applied mathematics from the University of the Free State. A Fulbright travel grant and a Cornell University Fellowship allowed her to pursue her passion for physics at Cornell University (United States), completing a PhD degree in theoretical physics. In 2005 she won the Sherman Fairchild Prize Postdoctoral Fellowship at the California Institute of Technology and spent five happy years in Kip Thorne’s group probing the nature of spacetime and working out its observational implications. Upon returning to South Africa, she continues to collaborate closely with the theoretical physics groups at Cornell and Caltech.
Electricity has become indispensable to most of the world’s humans, but producing it takes a heavy toll on the planet. Image: Ian Michler
Too clever by half Technology is at once a hugely constructive and a hugely destructive force, and for the most part we have been content to ignore the latter while enjoying the benefits of the former. But, suggests Ian Michler, it’s high time that we begin to think seriously – and innovatively – about tempering its damaging effects.
n the course of my research for last month’s diary, ‘The end of the line?’, one factor cropped up again and again: the role technology has played in our destruction of the oceans. In essence, global fishing fleets are using such advanced equipment that without the most stringent of controls, they will completely empty every marine ecosystem on earth. And it’s not only the oceans. The same applies to almost every facet of humankind’s development over the past century or more. As much as any other contributing factor, technology is responsible for the predicament our planet finds itself in. But say that out loud and most people will baulk at the idea. To admit the truth of it would mean having to change the way we think, behave and, ultimately, live. This is a very uncomfortable message for most of the middle and upper economic classes around the world. Let’s look at some of the hightech developments that we take for granted, like the combustion engine, super-tankers, plastic products, splitting the atom, deep mining techniques, drug manufacture and space travel. When they arrived on the scene they were all major advances, technologies that would make our lives easier and more successful. And, if we ignore everything but the direct impact they have had on individual lives, mostly they have done that. As time has passed, though, we now know that when viewed collectively as the primary compon-ents of our
means of production and consumption – in other words, our global footprint – their impact on the planet has been hugely significant and ultimately negative. Driven by the notion that a constantly increasing rate of economic growth is the overriding marker of a successful society, developing or purchasing more advanced technologies has become fundamental to fulfilling this aim. And with the array of new tools at our disposal, we have been able to reach further, deeper and higher into every imaginable ecosystem and exploit more effectively every possible resource. History indicates that most engineers or scientists side with the vested interests of the day, and it is also apparent that each generation of innovators has failed to consider the contra-indications or long-term consequences of their technologies. Spare a thought for the generation 50 years hence and what it may have to deal with because of today’s scientists who are forging ahead with genetic engineering. After well over a century of this developmental model, it is now difficult to argue that the world’s natural systems – so vital for our survival – are not faltering. In many in-stances, the impacts of technology have got out of control and it is now obvious that to continue on the same path would be very short-sighted. If technology is going to work for us, we need to change the way we develop
it – and certainly the way we apply it. Fortunately there is good news on this front. Many innovators are working on alternative technologies that embrace natural processes, ‘Cradle to Cradle’ (or regenerative) design concepts, reduced resource utilisation and nontoxic products (see the panel for examples). There is, of course, another possibility to consider: maybe our current behaviour is part of our genetic disposition, and the way Homo sapiens is following its evolutionary path cannot be controlled or modified, no matter how clever we think we are. ❑ Follow Ian’s take on other environmental issues at www.africa geographic.com/blogs/?cat=5
Check these out www.openplanetideas.com Open Planet Ideas aims to allow citizens of the world to promote possible solutions for today’s environmental challenges. www.greentechnolog.com The Green Techno Log is dedicated to showcasing an array of clean and low-impact technologies for the future. www.green-technology.org Green Technology promotes development from a different paradigm, with links to organ-isations and companies involved in cultivating technologies from almost every sector, including energy, building, waste and consumption. www.ecotech-intl.com EcoTech International promotes green building expertise, innova-tions and ‘cleantech’ technology. www.technologyreview.com The Technology Review provides information on emerging technologies and the impacts they could have on business and society.
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Is our universe the only one? It’s possible that there are gazillions of them in a multiverse. What would that be like? Image: Deviant Art
How little we know Chris Clarkson takes a look at what we do and, more importantly, don’t know about the universe in which we live.
n 2011 the Nobel prize in physics went to three cosmologists for ‘the discovery of the accelerating expansion of the Universe through observations of distant supernovae’. Saul Perlmutter, Brian Schmidt and Adam Riess share in the spoils and got to meet the King of Sweden. But what does their discovery mean? And what are the implications? The expanding universe It’s been known for about 100 years that the universe is expanding. Take any two galaxies and look at how they’re moving around in space, you’ll ﬁnd they tend to be drifting apart over time. The implications of this simple observation really are colossal. Working backwards in time in our minds, we see that galaxies must have been much closer together in the past than they are now. And the universe must have been hotter back then – compress anything you like and it heats up – far enough back it was hot enough so that atoms themselves did not exist. Even more dramatically, extrapolate further and there must have
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been some kind of Big Bang to start it all. Yet here we live some 14 billion years later, orbiting an ordinary star on the edge of a typical galaxy – a galaxy among many billions. The Big Bang The physics of what happened has been worked out in exquisite detail over the last 30 years or so. Other Nobel prizes to go to cosmologists were for the discovery and mapping of the ‘cosmic microwave background’, the famous afterglow of the Big Bang. This is the era when the universe was in transition from a plasma like the Sun to an era where stars and galaxies began to form. Even though this happened about 300 000 years after the Big Bang, we see the aftermath in every direction we look in space. There are literally microwaves everywhere, bathing us just a few degrees above absolute zero. More arrestingly, we see imprinted in the cosmic microwave background sky the tiny seeds of galaxies – really the origin of all the structure we are now a small part of.
Gravity, Einstein and cosmology This has been understood for quite a while now. So why are cosmologists getting another Nobel prize? The reason is because of their discovery that the expansion rate is speeding up: this really tells us that we don’t understand the bigger picture at all well. In fact one can argue we don’t understand the bigger picture at all. But before any creationists start waving their mad hats in the air, let me try to explain. Cosmology is really all about gravity – Einstein’s theory tells us exactly how to calculate the expansion history of the universe, from very, very near the beginning until today (and as far as you like to the future). From what we know in everyday life gravity is attractive. The peculiar force that keeps us glued to Earth and keeps the planets orbiting the Sun, extends inﬁnitely far into space, mingling and combining with the gravitational ﬁelds of all the other stars and planets and galaxies out there. The net effect of this is that galaxies attract each other, just like the Earth and the Moon do, only they’re so far apart it’s
Q Astronomy a very weak effect. Over time though, like a giant tangled web of elastic, these pull on each other and gently slow the expansion started in the Big Bang. Or so we thought in 1998. On top of this there seems to be something else at play acting against this mutual attraction: it really seems that the expansion is speeding up and not slowing down as we might expect. How did Perlmutter, Schmidt and Riess (and all the many poor unknowns working just as hard behind the scenes) ﬁgure this out? It’s not as easy as you might think. It’s hard, because to measure how far away distant galaxies and things are we need to know how bright they are if they were up close. But we don’t. Except, that is, for some sensational explosions called supernovae – exploding ‘white dwarf’ stars, which were dead but are brought back to life as they suck matter from a nearby star. As we know more or less the amount of mass that is converted into energy in such an explosion we can use the fact that they are nearly identical to ﬁgure out how far they are from us. (The explosions are prodigious – for a few days they will be brighter than the galaxy they’re in, brighter than 100 billion normal stars.) So, we can use these as ﬁreﬂies in a forest to map out the expansion of the universe over space and time. Astonishingly, observing only around 50 of these supernovae was enough to show that the cosmic expansion rate was not decreasing as expected but speeding up. The supernovae are much dimmer than expected in a normal model. We’ve seen about 500 supernovae now, and they still tell the same story. Compare that to comparatively limited information we have from observing millions of galaxies (we don’t know how bright they are), and we see how important scientiﬁcally supernovae are.
Dark energy Ok, so the expansion of the universe is speeding up. So what? Well, it seems that the implications could be just as spectacular as the discovery that the universe is expanding – perhaps even more. There really are very few plausible models for ‘dark energy’, or so the strange substance that is causing the effect has been dubbed. It could be something wrong with Einstein’s theory of gravity, but no one has yet come up with a working alternative.
A dead white dwarf star guzzles the atmosphere of a companion star. When it gets heavy enough its core re-ignites in a massive explosion. Image: : www.theness.com
The cosmic microwave background fluctuations are quantum fluctuations blown up to the size of our universe. They are the origin of all structure in the universe. Image: Courtesy the WMAP team – http://lambda.gsfc.nasa.gov/
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Simulations of structure reveal a tangled mass of clusters upon clusters of galaxies.
It could be some kind of ‘scalar ﬁeld’, perhaps like the Higgs boson only much, much, stranger. Maybe. The most recognised idea at the moment is that this observation tells us about the properties of the vacuum itself. When there’s nothing there, spacetime expands! Repulsive, you might say, but there’s now quite a lot of evidence for dark energy actually being vacuum energy (or a ‘cosmological constant’ in the jargon). It comes from piecing together everything we understand about cosmology from the earliest moments when hydrogen was synthesised, to today where we observe the interwoven web of clusters upon clusters of galaxies. Everything points to the cosmological constant – the simplest of all the explanations. The meaning of life Extrapolations to explain the existence and size of the cosmological constant are as bizarre as they are beautiful. Why do we live in a universe with the particular value of the cosmological constant we measure? Why do we live in a universe like this? How can a universe that is so balanced for
Image: Millenium simulation – Springer et al. (2005)
life just happen to exist? Why does anything exist at all? In short, wtf? Other clues come once more from the cosmic microwave background: it tells us that the universe must be very large indeed – somewhere between hundreds and 10100 of the size of our visible patch of the Universe, which itself is a few billion light years across. Imagine that! Once you get beyond 10120 patches the size of ours, things start repeating themselves, and your imagination can run pretty wild – just think what you might be getting up to in your other incarnations. On top of this, the neatest model for the Big Bang is ‘chaotic inﬂation’, where the universe went through a brief but monumental expansion to its gargantuan size. The quantum ﬂuctuations from the ‘inﬂation’ part are imprinted in the cosmic microwave background; we see them, they’re there. The ‘chaotic’ part means that such pandemonium can happen anywhere, anytime (though it’s not very likely). Some ideas from string theory postulate a whole ‘landscape’ where the inﬂation can wander, spewing out universes of all kinds as it does so – perhaps 10500 of them in a
‘multiverse’, or maybe many more. This explains the size of the cosmological constant because one of its mysteries is that its value in our universe seems ﬁnely tuned for life. If it wasn’t we wouldn’t be here, so we’d just be in another universe asking the same question (or a big-eyed slimy version of us would anyway). Given a big enough mutiverse, some of the baby universes have to be suitable for life. One of them must surely look like this. Pretty outrageous stuff. But it has to be – cosmology is trying to explain the whole Universe from start to ﬁnish. How could it not be amazing? The discovery of the accelerating expansion is a momentous part of an ongoing revolution in our understanding of the cosmos. Surely such a profound discovery deserves a Nobel prize? ❑ Chris is a cosmologist working at the University of Cape Town. He grew up in Scotland doing degrees at Edinburgh and Glasgow. He was a researcher in Canada, where he met his wife Vivian, before settling in South Africa. In his spare time he rides his bike, and now realises he’s too old to win the Tour de France.
FactFile Q String theory In order to understand the structure of our Universe at its deepest level, physicists look to answer every question and solve every mystery. We never stop asking ‘why?: Why did this happen? Because of such and such an effect. What was the cause of that effect? This body interacting with that one. Why did they interact? Because they feel such and such a force. What is the origin of that force? ... And so on. Jim Al-Khalili – Quantum: A Guide for the Perplexed Chris Clarkson’s article introduced the idea of the ‘multiverse’ and with it, string theory. He also spoke about the central role that gravity has in both our understanding of the Universe and also in putting together the so-called ‘theory of everything’. But what is string theory? Most physicists who are working on quantum gravity are trying to build on quantum mechanics – which is essentially the physics of the sub-atomic realm. These physicists say that we now have reasonable understanding of three of the four forces in quantum mechanics and so we should now be able to have a similar understanding of gravity. To do this, they have come up with string theory, which ultimately became superstring theory. String theory describes the force of gravity in terms of an exchange particle called the graviton. But string theory differs from all earlier quantum field theories because it describes all fundamental particles as tiny vibrating strings. The different frequencies at which these string vibrate give rise to all the different elementary particles. The early exponents of string theory came up against multiple problems when trying to give the theory some body – not least of which was the fact that the mathematics they were using to describe it was so complex that no-one really understood it! By the early 1990s there were five different versions of string
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theory and no one knew which was the correct one. But in 1995, there was Superstrings. Image: Wikimedia commons a second string revolution. M-theory was formulated, which took all the different superstring theories and put them under one umbrella. The M stands for membrane – instead of strings as the fundamental entities of our Universe, M-theory says that there should also be two-dimensional sheets, or membranes, or even strangely shaped three-dimensional blobs. However, there are those who think that the M should stand for mystery because no-one is quite sure what the equations for the theory look like. What we do know is that M-theory predicts that we live in a tendimensional space (plus time – which makes it 11 dimensions) and that six or seven of these dimensions are curled up far smaller than anything that can be accessed with today’s particle accelerators – they are trapped within the strings and the membranes.
‘Anyone who is not shocked by quantum theory has not understood it’ – Niels Bohr
Can anything travel faster than light? Chris Clarkson explains how Einstein’s theory of relativity appears to have been broken – but also why it has not!
The tracks left by neutrinos hitting hydrogen atoms.
Albert Einstein, explaining the theory of relativity. Image: www.asrema.com
What’s faster than light?
t the end of last year (2011) a rather peculiar phenomenon was seen: neutrinos appear to be able to travel faster than light. Einstein’s theory of relativity is debunked! Except nobody believes it. It’s a perfect example of science in action. Over several years a team of scientists working at CERN in Switzerland have been trying to measure the speed of a strange type of particle called a neutrino. These particles are extremely light and extremely elusive: they don’t interact with things the way we’re used to (‘electromagnetically’), yet they are everywhere. About a trillion are passing through you every second, and it’s probable that not a single one will nudge any part of any of the atoms of which you are made. On a day with the Sun overhead, those neutrinos pass right through the Earth, with scarcely a handful knocking into anything at all. It’s a bit like light passing through air or glass – we can see through air because the light rarely hits the molecules that make it up. Not surprisingly, it’s taken scientists a long time to measure the properties of these neutrinos – they’re quite hard to detect. Scientists who work on the physics of very small particles designed an experiment to do just this. The plan, in an experiment called OPERA, was to ﬂash a pulse of neutrinos from Geneva to their lab in the north of Italy, 700 km away. If you tried it with light it wouldn’t work because over that distance the curvature of the Earth gets in the way. But neutrinos don’t care about things like that. They just travel straight through the Earth’s crust as if it wasn’t there at all. And then they travel straight through the detectors OPERA built and off into space. Well, all but a few do anyway. It’s a neat experiment because even though they can only detect a few of them,
they are interested in the time it takes to get there from when the pulse was ﬂashed. With GPS technology and a very fancy stopwatch, the scientists found it took the neutrinos about 60 nanoseconds less than light would over the same distance. That’s not much of a big deal right? What’s a few nanoseconds between subatomic particles? Well, the thing is that it could be a very very big deal indeed. In 1905 Einstein revolutionised physics to such a degree that the world has never looked the same since. His theory of relativity underpins every aspect of fundamental physics, from the way the universe expands to how particles zip around CERN. At its core is an assertion that the speed of light is a (very large) constant, which everyone measures the same. That means (although it’s not obvious) that the speed of light is the maximum speed that anything at all can go at, and that only particles with no mass whatsoever can attain it (they cannot do anything but travel at the speed of light in fact). This has been seen to be correct so often that it’s almost inconceivable that it could all be wrong. Almost. Einstein’s theory at its core actually allows for a phantom type of particle known as a tachyon which can never go slower than light. In the same way normal things are trapped in our slow lumbering world, tachyons are trapped too, but with a speed limit of a very different kind. Two worlds in the same space, forever separate. It would take energy to slow these things down rather than speed them up; apply the brakes and they go faster! If these particles really existed then all sorts of crazy things become possible (at least theoretically), such as being able to make a telephone to chat to yourself in
the past, or even time travel to the past. So, not many people believe this sort of thing is possible. Other explanations may be stranger still. Some theories would have us believe that there are extra dimensions to space above the three that we are forced to inhabit – a bit like being trapped in a ﬁxed world in a computer game. If neutrinos can travel in this extra dimension they can just take shortcuts we can’t – but without breaking Einstein’s precious principle. Sadly, the most likely explanation for our neutrinos is the most mundane: there’s something wrong with the experiment. Not because the experimenters screwed up, but rather there’s something wrong in the setup of the experiment that no one has spotted yet. Are their clocks accurate enough? Have they measured the distance correctly? Is GPS really accurate enough? Have they calculated the curvature of spacetime around the Earth correctly? And on and on and on. It’s just really hard to measure things accurately. So that’s why nobody really believes it’s real for the moment, including the experimenters themselves. What we look for before something becomes a ‘fact’ in science is independent conﬁrmation by a completely different team of researchers with a completely new experimental setup. But if they do ﬁnd the same thing then we really are in for a very big surprise indeed. I’d love to chat to 20-year-old me. ❑ Chris is a cosmologist working at the University of Cape Town. He grew up in Scotland doing degrees at Edinburgh and Glasgow. He was a researcher in Canada, where he met his wife Vivian, before settling in South Africa. In his spare time he rides his bike, and now realises he’s too old to win the Tour de France.
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SAASTA AWARDS SCIENCE COMMUNICATION SAASTA/NSTF AWARD
Awarding excellence in science communication for outreach and creating awareness of science, engineering, technology and innovation. This award is made annually to South African journalists, researchers, writers, educators, academics, specialist science communicators or science centres who have made a substantial impact on public awareness of science, engineering and technology. The award is open to anyone who has published articles in any South African print medium, and/or broadcast on any South African radio or television programme, and/or who has communicated Science and Technology regularly in other innovative ways, such as through drama, cartoons, exhibitions, or public lectures during the past five years. Winners will be announced at the NSTF-BHP Billiton Awards Gala Dinner on 21 June 2012. Nominations are now open. Visit www.nstfawards.org.za for details. Nominations close 29 March 2012.
SAASTA/NSTF Award Winner 2010/2011: Mr Kevindran Govender (centre), with Minister of Science and Technology, Mrs Naledi Pandor (l) and Mr Lorenzo Raynard of SAASTA (r). Mr Govender was awarded for demonstrating that astronomy is a powerful tool for science education, communication and development.
YOUNG SCIENCE COMMUNICATORâ€™S COMPETITION Calling young scientists to communicate and connect
Scientists are by nature passionate people. This passion can be reflected in the way science is communicated, engaging an audience and igniting enthusiasm for science. The Young Science Communicatorâ€™s Competition (YSCC) challenges young scientists and researchers between the ages of 20 and 35 to communicate their world to a larger audience beyond their scientific community. This may be through media such as the written word, radio, drama, or even new media like viral video. YSCC is a biennial competition, running this year in 2012.
Visit www.saasta.ac.za for updates on YSCC categories, entry requirements and closing dates
Nanotechnology and nanopar t icles: should we be concerned about our health? Can nanoparticles harm us? Riëtha Oosthuizen looks at the possibilities.
nything described by the prefix ‘nano’ would be considered to be small, since the word is derived from the Greek word for dwarf. Nanoparticles are considered to be those particles below 100 nm in at least one dimension. One nanometre (nm) is one-billionth of a meter (10-9 m), or to put this into context – 1 nm is about 1/80 000th the width of a human hair. It is generally accepted that ‘nanotechnology’ refers to the deliberate creation (through engineering processes) and use of particles less than 100 nm. Nanotechnology does not include those nanoparticles that form unintentionally, for example during combustion processes, or those nanoparticles present in the natural environment, such as viruses.
A nanoparticle – the buckyball or C60 – so-called because it contains 60 carbon atoms.
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Image: Dr Manfred Scriber, CSIR
Unique characteristics of nanoparticles Using modern technology, it is possible to expose matter to extreme conditions, such as extreme cold or a vacuum, which can then change its properties. When particles become very small there are more atoms on the surface than inside the particle (a particle with a 10 nm diameter has approximately 20% of its atoms forming the surface, whereas a particle of 1 nm in diameter has about 90% of its atoms forming the surface). Atoms on the surface may have different properties to those inside the particle. In other words, because they are so small, nanoparticles have a much larger catalytic active surface area than larger particles of the same material, when the mass of the two sets of particles is the same. This means that nanoparticles may behave like new chemical substances. It may also mean that materials that are
biologically inert may become harmful in nanoparticle form. Engineered nanoparticles with their unique properties are designed for specific functions. Their unique properties can enable materials and devices to be smaller, stronger and using less energy than those currently in use. Carbon nanotubes are, for example, about six times stronger than steel, albeit much lighter and therefore are ideal for use in cables. Certain nanoparticles are able to cross barriers, such as the blood-brain barrier, and are used in drug delivery including chemotherapy. Potential for human exposure Tons of nanoparticles are already being manufactured and used in more than a 1 000 consumer products, such as cosmetics and sunscreens, also in tyres, electronics, self-cleaning surfaces, filters and fuel cells to mention but a few. It is therefore to be expected that these particles will be introduced to the environment through spillages, effluent and/or landfills. Humans are, and will be, exposed to nanoparticles, not only occupationally but also in the environment and through the use of consumer products containing nanoparticles. The fate and transport as well as the effects of naturally occurring and unintentionally created nanoparticles are largely known. These include inflammation of the lung and development of artherosclerosis (thickening and hardening of arterial walls) in healthy humans. However, much less is known about the fate, transport and health effects of engineered nanoparticles. This is especially true for those particles that have been designed to have specific properties, for example those that do not dissolve or biodegrade. The fact that nanoparticles are small enough to enter deep into the lung and cross cell membranes and biological barriers to the brain and placenta is worrying. Although there are many ongoing toxicological studies on nanomaterials, there are still huge uncertainties and even contradictions in research results. The history of asbestos and DDT has told us that harmful effects may only be established years after implementation of chemicals, when much damage has already been done. Research on the toxicity of nanoparticles is very important, because if the toxicological
1 kg of particles of 1 mm3 has the same surface area as 1 mg of particles of 1 nm3.
Image: Wikimedia commons
Diseases associated with nanoparticle exposure.
Image: Wikimedia Commons
potential and mechanisms of action of nanoparticles are understood, it will be possible to engineer safe nanomaterials. Some action groups feel that the ‘precautionary principle’ (which means anticipating harm before it occurs) should be applied. This means that due to the lack of knowledge about the risks these engineered particles may have, the development should be stopped until such time as the risks have been scientifically established. Currently most scientists do not consider nanoparticles as completely harmless to human health and the environment, but the majority are also
not of the opinion that development and production should be stopped immediately. However, they do feel that studies to determine the human health and ecological effects should go hand in hand with development. ❑ Riëtha Oosthuizen is a senior scientist with more than 20 year’s experience in the field of air pollution and human health and registered with the Health Professions Council of South Africa as a medical scientist. She is focussing on the impact of chemicals and particulates in air on human health, as well as on factors that make communities more vulnerable to these impacts.
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Research that can change the world
Impact is at the core of the CSIR's mandate. In improving its research focus and ensuring that it achieves maximum impact in industry and society, the organisation has identified six research impact areas: Energy - with the focus on alternative and renewable energy. Health - with the aim of improving health care delivery and addressing the burden of disease. Natural Environment - with an emphasis on protecting our environment and natural resources. Built Environment - with a focus on improved infrastructure and creation of sustainable human settlements. • Defence and security - contributing to national efforts to build a safer country. • Industry - in support of an efficient, competitive and responsive economic infrastructure. • • • •
Think before you walk There’s a decided feel-good factor to cuddling a lion cub or riding an elephant; it’s something that, given half a chance, many of us would do without thinking twice. But would we be contributing to research and conservation, as wildlife-encounter operations claim? Probably not, says Ian Michler.
ver the past decade there has been a proliferation of enterprises across Africa that offer interactive or close-encounter experiences with wildlife; sign up and you can walk or romp with a wild animal, cuddle it or even ride it. Such operations include primate and bird parks, elephant-back riding and diving with crocodiles, and the most popular are those that feature the large cats. The abundance of experiences on offer may have something to do with the current trend in wildlife television programming, which fosters a provocative approach. It seems that almost every nature-based TV series aired today has staked its revenue stream on a lead character harassing wild animals and, if you believe the directors and marketers, they always do so in the name of education or for the benefit of science and conservation. There is no doubt that humans feel a powerful emotional desire – even need – to be involved in caring for and conserving wild animals, and it is this sentiment that organised wildlife encounters so effectively tap into. But, if the truth be told, supporting such enterprises may well have the opposite effect. Some of them take a frank approach and sell themselves for what they are – commercial ventures that rely on the lure of a ‘touchy-feely’ encounter. But there are many others that have a deceptive tagline, promoting themselves under the banner of conservation, science or education in an attempt to acquire legitimacy for their activities. And, although organisations such as these may be supported by a sector of the general public and some of the large local and international tour operators, they find little favour within the wider conservation and wildlife management communities. These communities’ attitude to the African Encounter and Antelope Park outfits that run the ‘Walk with Lions’ operations in Zambia and Zimbabwe suggests that they, for example, fall into the latter category. Both are directly linked to the African Lion and Environmental Research Trust (ALERT), which attempts to legitimise their lion captive-breeding programmes and money-spinning tourist operations.
Having been eliminated from 70 per cent of its original range in Africa, the lion is in dire need of conservation whose foundation is hard research, not sentiment. Image: Ian Michler
It claims that charging visitors large sums of money to walk with sub-adult lions and cuddle captive-bred cubs is justified because the outfits are involved in datacollection and reintroduction programmes. Is it coincidence that they have set up shop in towns that draw substantial numbers of tourists to view the Victoria Falls, one of Africa’s iconic sights? What’s more, these outfits list a number of volunteer agencies as ‘supporters’. Persuading foreign volunteers to pay for an African experience on the basis that the work they do is beneficial makes for an extremely lucrative business model. But further invest-igation reveals that most of the volunteer agencies are also linked to the ALERT network. And, ALERT’s vigorous efforts notwithstanding, not a single recognised carnivore conservation or research institution in Africa or elsewhere will have anything to do with it. Panthera, a respected global organisation involved in wild cat conservation (www.panthera.org), brings together the world’s felid experts to direct and implement effective management strategies. Notable exceptions from this pool are ALERT and its sister bodies. Dr Guy Balme, a well-published scientist
on various issues relating to big cat conservation, is the director of Panthera’s lion programme in Africa. ‘Reintroducing captivebred and human-imprinted lions into natural ecosystems is almost always problematic,’ he says. ‘The cats are typically killed by other lions or end up in conflict with neighbouring communities, often endangering human life. We need to focus instead on the key reasons for population declines – habitat loss and the indiscriminate killing of lions and their prey.’ As all conservationists know, income for their work is limited. ‘It is very easy to raise money when cuddling cubs is involved, but these are tame animals with no chance of ever going back into the wild,’ adds Balme. ‘These organisations divert much-needed funding and attention away from legitimate carnivore conservation efforts.’ There’s little doubt that lions are in dire need of protection; they’ve been eradicated from more than 70% of their original range in Africa. But if you want to support lion conservation, get involved with the recognised organisations that are actively conserving wild populations and their habitats. ❑ Follow Ian’s take on other environmental issues at www.africageographic.com/blogs/?cat=5
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Geology – A science and a career By Craig Smith
The Halfway House granite.
Image: Carl Anhaeusser
The beautiful granites of the Augrabies gorge.
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Image: Craig Smith
eology is all about the science of the Earth and planets, and compared to many other scientific fields it is a very broad topic. Many of us who practice geology prefer to call ourselves ‘earth scientists’ because the range of possible career paths is very wide indeed. Earth science can encompass everything from the generation of energy from fossil fuels, exploration and mining of minerals, palaeontology (the study of ancient life recorded in fossils), to the study of ancient climate change (before humans!). One thing all earth scientists have in common is an appreciation and understanding of ‘deep time’ – time scales far in excess of a human lifetime and even in excess of the age of the human species. While geology has its origins in ancient Greece, our current understanding of the Earth is a very recent development of the past hundred years or so. And South Africa and South African earth scientists have played a key role in the coming of age of geology. The Sea Point Contact in Cape Town is a contact zone between two types of rocks that demonstrates conclusively that molten rocks exist in the Earth. In the mid19th century that was a revelation. The Contact was made famous by Charles Darwin who visited Cape Town on
his epic voyage to South America and the Galapagos Islands in the eastern Pacific Ocean. Charles Darwin, although best known for his work in evolution (also revolutionary at the time) in fact spent most of his time being a geologist. In the early 1900s physicists first recognised the phenomenon of radioactivity, but it was geologists who came up with a very important application – determining the age of rocks using radioactivity – thereby demonstrating the ancient age of the Earth. Some of the first very accurate age dating of rocks using modern ‘geochronometers’ was done in South Africa in the 1960s. The fact that the Earth’s surface is constructed of some 15 or so major crustal plates that move relative to one another (now called continental drift) was first envisaged by Alfred Wegener in 1912, following on from the work of several others. One of South Africa’s greatest scientists, Alex du Toit, in the 1920s and 1930s, was a key supporter of the theory, based on his geological observations in the field, and documented in his 1937 book Our Wandering Continents. But his work was so far ahead of his time, that it took until the 1970s for the scientific world to accept ‘plate tectonics’ as the major influence on
Q Careers The Sea Point contact is a frozen image in time, showing the contact between the older dark siltstones of the Malmesbury Group and the original hot magma that intruded. Image: Mike Golby
even work in an investment bank. Many geologists become managing directors or chief executives of companies. One thing is certain: in a world hungry for natural resources there are not enough highly skilled and experienced geologists to fill the existing vacancies. It is not unusual for geologists to change career directions several times in their working lives, and it is also likely that a geologist will travel extensively not just in their own country, but throughout the world. Many geologists have visited most of the continents, and some have even worked on the seventh continent, Antarctica. Geologists are ‘cosmopolitan’ by nature, and typically enjoy experiencing different cultures and countries.
the Earth’s geological structure. So what are the various subdisciplines of geology as practiced today? They include economic geology, mineralogy, structural geology, tectonics, engineering geology, geochronology, geochemistry, mineralogy, hydrogeology, geomorphology, petrology, sedimentology, geophysics, palaeontology, environmental geology, marine geology, petroleum geology, mining geology and field geology. These are only a few of the interesting options available. Why don’t you look up some of these terms on Google or Wikipedia for an explanation. Career paths Career paths in the earth sciences can be very broadly defined as academic (teaching and research in a university environment), industry (exploration for and mining of minerals), or government. Each of the earth science disciplines listed above has applications across the entire employment spectrum and each of these employment sectors has a variety of employers as well. For example, a specialist economic geologist with knowledge of exploration and mining could work for a global mining company, be selfemployed as a consultant, or could
Training However, to be eligible to claim one of these jobs, you need serious training. You have to have strong science and mathematics backgrounds, and you will need a three-year university Bachelor of Science degree plus a fourth year at Honours level as a minimum. Going on from there, a masters degree (MSc) may be necessary, and for employment in a university, a doctoral degree (PhD) and a demonstrated ability to conduct research and development is generally the expected level of education. A great deal of time and effort has to be invested in any science-related career path, and geology is no exception. But if you are interested in the subject, it will lead you on a fulfilling life time career path as a recognised and respected professional in your area of expertise. Most South African universities have world-class earth science departments that will give you a great undergraduate grounding in geology. And because of the importance of geology to the South African economy, South African geology departments and their graduates are recognised world-wide. For more information, go to the Faculty of Science offices at the university nearest to you, where you can ask about the undergraduate earth science programmes that are available. ❑ Dr Craig B Smith is the manager of the Geological Society of South Africa.
Q News A watery planet An international team of astronomers led by Zachory Berta of the Harvard-Smithsonian Center for Astrophysics (CfA) made the observations of the planet GJ 1214b. ‘GJ 1214b is like no planet we know of,’ Berta said. ‘A huge fraction of its mass is made up of water.’ The ground-based MEarth Project, led by CfA’s David Charbonneau, discovered GJ 1214b in 2009. This super-Earth is about 2.7 times Earth’s diameter and weighs almost seven times as much. It orbits a red-dwarf star every 38 hours at a distance of 2 million kilometres, giving it an estimated temperature of 230 ºC. In 2010, CfA scientist Jacob Bean and colleagues reported that they had measured the atmosphere of GJ 1214b, finding it likely that it was composed mainly of water. However, their observations could also be explained by the presence of a planet-enshrouding haze in GJ 1214b’s atmosphere. Berta and his co-authors, who include Derek Homeier of ENS Lyon, France, used Hubble’s Wide Field Camera 3 (WFC3) to study GJ 1214b when it crossed in front of its host star. During such a transit, the star’s light is filtered through the planet’s atmosphere, giving clues to the mix of gases. ‘We’re using Hubble to measure the infrared colour of sunset on this world,’ Berta explained. Hazes are more transparent to infrared light than to visible light, so the Hubble observations help to tell the difference between a steamy and a hazy atmosphere. They found the spectrum of GJ 1214b to be featureless over a wide range of wavelengths, or colours. The atmospheric model most consistent with the Hubble data is a dense atmosphere of water vapour. ‘The Hubble measurements really tip the balance in favour of a steamy atmosphere,’ Berta said. Since the planet’s mass and size are known, astronomers can calculate the density, of only about 2 grams per cubic centimetre. Water has a density of 1 gram per cubic centimetre, while Earth’s average density is 5.5 grams per cubic centimetre. This suggests that GJ 1214b has much more water than Earth does, and much less rock. As a result, the internal structure of GJ 1214b would be extraordinarily different from that of our world. ‘The high temperatures and high pressures would form exotic materials like “hot ice” or “superfluid water”, substances that are completely alien to our everyday experience,’ Berta said. Theorists expect that GJ 1214b formed further out from its star, where water ice was plentiful, and migrated inward early in the system’s history. In the process, it would have passed through the star’s habitable zone, where surface temperatures would be similar to Earth’s. How long it lingered there is unknown. GJ 1214b is located in the constellation of Ophiuchus (The Serpent Bearer), and just 40 light-years from Earth. Therefore, it’s a prime candidate for study by the NASA/ESA/CSA James Webb Space Telescope, planned for launch later this decade.
An artist’s concept of the watery planet.
Image: NASA, ESA, and
David Aguilar (Harvard-Smithsonian Center for Astrophysics)
Quest 8(1) 2012 45
Grapes, genes and climate change W Dr Wilmot James delivered the AGEI & UCT’s Division of Human Genetics Darwin lecture on 10 November 2011.
The Pinot Noir grape.
Image: Wikimedia commons
46 Quest 8(1) 2012
ine is one of the great joys of life and it is important to our economy. In our book Grape: Stories of the Vineyards in South Africa, Jeanne Viall, Jakes Gerwel and I used the grape to tell stories about the people who work with it as workers, winemakers, scientists, farmers and exporters. And we tell the story of Pinotage, South Africa’s only wine cultivar. Pinotage was developed by Abraham Perold by pollinating Hermitage (Cinsaut) with Pinot Noir to create a cross that had the best characteristics of the parents: the classic Burgundy taste with the easy-to-grow, disease-resistant Cinsaut. His experiment yielded four seeds which were planted in his garden and later moved to Elsenburg Agricultural College. The first commercial planting of Pinotage was on the farm Myrtle Grove near Sir Lowry’s Pass in 1943. In 1959 and 1961 Pinotages from Bellevue and Kanonkop caused a sensation at the Cape Wine Show when they emerged as champion wines ahead of classic red cultivars. The native territory for the forebears of what became today’s domesticated grapes (Vitis vinifera) is the region that today makes up Iran, western
The post house at the top of Sir Lowry’s Pass. Image: Wikimedia commons
appellations controlees their cachet – the essence of wine lies in its nurture.’ Not quite, said the plant geneticists. In genetics it is never only nature or nurture at work, but always both. Geneticists have found hundreds of genes that produce flavours and aromas in wine grapes. Work on the grape genome shows that the parent grapes for Pinot Noir were very different, genetically. The implications are twofold: firstly, there is the opportunity to explore genetic diversity for novel flavours and aromas, and more consistently good flavours can be engineered. Secondly, knowing these genes creates the potential to build greater immunity against plant pathogens so wine grapes can be grown in areas that might otherwise be inhospitable to the vine. Sequencing the Pinot Noir genome turned up 289 genes which relate to disease resistance. Yet in spite of this, ‘pinot noir remains susceptible to several fungi, bacteria and viruses possibly due to a defective system for recognising pathogens,’ according to Science Daily. ‘Pinot Noir can be crossed with many wild grape species providing a large reservoir of disease-resistant genes, which can be exploited with the aid of this genome road map.’
COP17 – the United Nations gathering to tackle climate change – [met recently] in Durban. It’s a good time to talk about how nature, and what we have done to it, impacts on the ‘terroir’ of grapes. What are the effects of climate change on the traditional grape-growing areas of the country and which adaption strategies are best? Research shows significant trends will occur in rainfall and air temperature, and climate change is projected to lead to warmer and mostly drier conditions in the wine growing parts of South Africa. Also predicted is a higher incidence of extreme events, such as severe storms. Records from 12 weather stations in the Cape, between 1967 and 2000, show that very warm days have become warmer, particularly during the past decade. In the future, temperatures are expected to rise in the south western Cape by about 1.5 ˚C along the coast and by about 2 ˚C to 3 ˚C inland of the mountains by 2050. How will this affect viticulture? Vines are hardy and produce better fruit when made to struggle. But how much struggle can they take? A change in climatic patterns will affect wine production and such impacts are already being felt within the South African wine industry both
Turkey, Armenia, Azerbaijan and Georgia, where the ancestor to Vitis vinifera still grows wild. A recent study of grape genes suggests that the grape was domesticated about 8 000 years ago and migrated from its Near East origins first to Western Europe and then in waves to the rest of the world, following human migration patterns. The earliest acts of cultivation favoured the self-fertilising members of the species. Over time, grape selection went through weak so-called genetic bottlenecks, meaning they retain considerable genetic diversity, offering potential to harvest desirable traits in taste and texture. After the sequencing of the Pinot Noir gene, the Economist noted in December 2009 that the ‘battle between those who think character comes from nature and those who think nurture is the key is not confined to students of humanity’. ‘It lies at the wine-making too. For European growers, the variety of grapes is important, of course. No one would mistake cabernet sauvignon for sangiovese or riesling or chardonnay. But grape varieties are normally propagated as cuttings – clones. What creates a wine’s character, they argue, is the terroir – that mysterious combination of soil and microclimate that gives the
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A view of Helderberg and Somerset West from Sir Lowry’s Pass showing vineyards.
A vineyard in the Stellenbosch.
Image: Wikimedia commons
directly, in terms of physical changes in climate, and indirectly, as growing environmental awareness amongst consumers drives demand for carbonefficient produce. The wine industry here has been characterised by its geographical diversity, but this is threatened by climate change. When a warm region becomes hotter, diversity in the type and style of wine is more limited. On the other hand, the industry is situated in an area where there is still potential for further expansion into temperate and cool areas, for changes in viticultural and oenological practices, and for changes in wine styles. Suzanne Carter, an environmental
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Image: Wikimedia commons
and geographical scientist at the University of Cape Town, says climate change will impact on the South African wine industry in four main areas: changes in rainfall; extreme events; temperature; and carbon dioxide levels in the atmosphere. Rainfall will decrease in the Western Cape, but by how much isn’t known. Most vineyards use irrigation. Currently most farmers don’t use their full quota of irrigation water and therefore could possibly draw more water as temperatures rise. As demand for water increases, wine producers will pay more per unit of water, impacting on costs. The distribution of rainfall events is
also a concern. In the past 50 years there has been an increase in the number of dry days between rainfall events. If dry-spell duration increases, the period of increased evaporation also increases. Peter Johnson, with the UCT Climate Systems Analysis Group, say: ‘Grape people don’t want rain, especially summer rain. They want dams and rivers full, but not rain.’ Extreme events are also expected to happen more often with climate change. Heavier rains, happening less frequently, are not always desirable, as a lot of water is lost to runoff. Floods may also ruin agricultural crops. Increased drought is of great concern. Irrigation can be used to offset any deficit; however, if there are water restrictions or an increased demand for water, it will become increasingly difficult to provide supplemental irrigation, writes Carter. Temperature increases, so far, have improved the quality of wines. But in some areas, where the warming has been more pronounced, there seems to be a threshold over which quality is sacrificed if ripening occurs too early. Each cultivar and style of wine grape will have different susceptibilities and coping ranges. There is some speculation as to the resilience of vines to adapt to climatic stress, says Carter. Greater resilience may make the vine more water efficient; however, it’s unclear whether this may affect wine quality. Vines produce better quality fruit when they have struggled, producing smaller, better quality yield. But if yields become too small, the capital invested in the vines is not recouped in sales. Carbon dioxide increasing in the atmosphere encourages growth of larger fruit and yields, and it increases water efficiency in the vine. But this may produce higher sugars that would change the flavours and, potentially, the quality of the grapes. ❑ Dr Wilmot James MP is the Chairperson of the African Genome Education Institute (AGEI) and Honorary Professor in UCT’s Division of Human Genetics. This is an excerpt of his lecture, delivered on 10 November 2011, as part of the 2011 Darwin Seminars hosted by the AGEI & UCT’s Division of Human Genetics. The lecture was dedicated to science journalist Christina Scott who died on 31 October 2011.
Q News Worms wage war on waste
In support of Nelson Mandela Metropolitan University’s (NMMU) ongoing ‘greening’ activities, second year Agricultural Management students are turning residence kitchen waste into high quality compost – using earthworms. The rich humus excreted by the earthworms provides nutritious growing material – a safer, equally-effective alternative to synthetic fertilisers – for the students’ organic vegetable garden. To stimulate the process, called ‘vermicomposting’, the students have set up an earthworm bed using vegetable scraps and peelings from North Campus’s Lebombo Residence. Agriculture and Game Management lecturer, Timothy Pittaway said the purpose of the earthworm farm was to help students understand the benefits of these invertebrates to crop production. ‘Earthworms reduce farmers’ reliance on purchased fertilisers, which leads to lower production costs and at the same time increases soil productivity.’ Essential micro-organisms pass into the soil in the worms’ excrement. Eating up to half their body weight in food every day, earthworms help to reduce waste volume too. ‘We hope this project will expand and become part of NMMU’s Green Campus Initiative.’
Brewing beer, producing wine and making cheese have quite literally added a dash of flavour and fun to third year microbiology practicals – thanks to the introduction of a South African Breweries (SAB)-sponsored microbrewery on campus last year. Spin-offs include an annual cheese and wine event for the microbiology students – where everything is classroom-made – and the introduction at Nelson Mandela Metropolitan University (NMMU) of a popular Microbrewery Society, in which members concoct their own high-quality speciality brews for participation in national brewing competitions. Last year, they also made beer for a German Day function on campus. Microbiology lecturer, Dr Sharlene Govender said the purpose of the SAB-sponsored microbrewery was to help the university “teach the science of brewing and train students (both in engineering and science) wishing to pursue careers in brewing”. ‘It creates a facility where research can also be conducted on a pilot scale, and links industry to the university to facilitate knowledge exchange in both directions.’ Use of the microbrewery forms part of the Industrial Microbiology and Biotechnology module in the BSc (Biochemistry and Microbiology) programme. ‘This module provides an overview of industrial microbiology and biotechnology as an applied biological science and how it impacts on our lives as consumers and citizens,’ said Govender. The microbrewery was constructed by microbiology academic Prof Tim Downing and former BSc honours student Phumlani Tetyana.
Second year Agricultural Management student Malahle Lebone gets to grips with a handful of red wiggler worms (earthworms), which are turning campus kitchen waste into compost. Images: NMMU
Cheers ... microbiology lecturer Dr Sharlene Govender, South African Breweries (SAB) manufacturing and technical director Clifford Raphiri and microbiology masters student Kyle van der Holst toast the launch of NMMU’s new SAB-sponsored microbrewery.
• Community and Health Sciences • Arts • Education
Quest 8(1) 2012 49
GPS systems are now incorporated into many smartphones. Image: Wikimedia commons
Why do we learn mathematics at school? What is the purpose of encouraging students to allegedly endure heartache and anguish on a daily basis? Quest’s resident maths fundi, Steve Sherman, explains why we should all like maths.
Real-life problem solving
S Remember vynil records? They were analogue sound storage mediums, while the CD is a digital storage medium. Image: Wikimedia commons
Sample based synthesis.
Image: Wikimedia commons
50 Quest 8(1) 2012
ome people associate mathematics with nerds and monotony. Others describe maths as a cure for insomnia. Many students will describe the gratuitous emotional pain they encountered while attempting to simplify or solve for X. What does X have to do with anything? Some students will even tell you that they don’t actually like mathematics and cannot see any logical reason to stick with it, especially if they are going to be studying in the arts and humanities field after school. So I am eager to convince you that maths is actually the one getting a raw deal! I will point out the reasons why we cannot live without maths and I will also share ideas on how we actually need it to make the world go round! Let me begin by asking the question: Do you like music? 98% of students respond yes to this almost rhetorical question. Yet when I ask an assembly full of students: Do you like maths? I find that only about 50% say yes. What is my point? Well if I had to ask you do you like opera? Students would mostly say no, yet they still continue to like music. Maths is no different! You might not like one aspect of maths, like doing loads of sums or maybe trigonometry but there are still many other parts of maths that you might indeed like (some you
might never have been exposed to!). So it is unfair to say you don’t like maths just because you don’t like one aspect of it. If you think music has many facets to it, then maths has so many more! Maths is cool! This article will introduce you to some of the very cool aspects of maths. It will demonstrate that maths does have a sexier side! Let’s begin with something that you can all relate to: cell phones. Most people have one of these marvels of modern technology. Thanks to mathematics, all your SMSs, GPS coordinates, MMSs and calls are transmitted safely from one phone to another. The signals are encoded and then decoded using the handsets. Codes and cryptology is a fascinating section of maths. It is used by the military and it is the backbone of every computer, piece of software including the Internet. Not exactly something you can live without! But wait, there is more! Back to the topic of music. Most music makes use of mathematical formulae to compress sound bites into MP3 files. These files are then played on various devices like iPODS and MP3 players. The music that is created nowadays relies heavily on synthesisers and computer software to alter voices, instruments and mix in beats and
Image: Steve Sherman
sounds. These rhythms and beats follow certain patterns (hint: maths also focuses on patterns). What, did I forget to talk about sport? Most teams in the world use software to analyse their games afterwards with complicated maths formulae to identify the strategies of their opponents. They can also measure the speed of a swing, the bounce of a ball and the strength of a rugby player. Using basic data handling, sport scientists can predict behaviours, improve techniques and create better, stronger and faster athletes. Why stop at sport when we can talk about the building you are sitting in? Buildings are not designed to just look pretty. Some are designed to withstand earthquakes and major disasters. Some buildings bring function, form and design to new levels. The mathematical designs, the calculations of forces that apply to balconies, roofs and structures will determine the limitations of a building. Determining the cost to ‘pimp’ your room requires a plan, a budget and price comparisons to ensure your room looks hot while keeping the price down. Helping real people I guess there are even more important applications of maths that many of
This architect’s drawing shows an elevation taken from a plan. Image: www.residencesatgreentails.com
us take for granted. Take my friend Nicky Abdinor as an example. Nicky was born without arms and yet she drives around Cape Town! You are probably wondering how she does it. How does she send me SMSs? How does she become a qualified clinical psychologist and run her own business? Nicky needs to solve problems on a daily basis that we just all take for granted: Washing your hair, grabbing the ticket out of the parking machine at the entrance of a shopping centre, etc. Nicky needs her maths brain to solve these and other types of problems! To find out how she drives her car without arms watch this video: http://vimeo. com/34143219 and to learn more about Nicky and her goal of helping disabled people to drive, visit www. nickysdrive.com. So let me ask you now – do you think that you could like some of these interesting aspects of maths? ❑
The Frank-Lloyd Wright water house.
Image: Wikimedia Commons
Steve Sherman was voted fifth best looking mathematician in the world by his mother. His mother contested this and now he is ranked sixth! He knows karate, Ju-jitsu and three other Japanese words.
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African mammals Smithers’ Mammals of Southern Africa: A field guide. Revised and updated by Peter Apps. (Cape Town. Struik Nature. 2012.) Mammals are always an easy sell. They are often large, attractive and some even appear to be cuddly. Field guides to mammals, on the other hand, can be difficult to produce. The group are very varied in size and habitat and require detailed illustrations or photographs for identification. The big cats are relatively easy – few of us need a field guide to distinguish a lion from a cheetah for example. But then there are all the small mammals, the mice, the bats and so on, that are not often seen, can be quite similar in appearance and are difficult to identify. Reay Smithers first put together Land Mammals of Southern Africa – A Field Guide a quarter of a century ago. Since the first publication of this book there has been a steady expansion of knowledge about southern African mammals, and in the 12 years since its third edition there have been major changes in our understanding of the evolutionary relationships among mammals. This book is the fourth edition of the ‘small Smithers’and incorporates both updated information on field biology and the new names of species and higher taxa that reflect the recent changes in systematics and taxonomy. However, it does not read like a textbook. It is small enough to be portable and the species are arranged in taxonomic groups that look similar to make comparisons easier, so the order does not necessarily reflect systematic relationships. Symbols are used to show the animal’s main activity periods and the species’ IUCN Red List classification. Each species is also accompanied by a spoor drawing showing the full track of the right forefoot and hindfoot – as though the animal were walking over soft, moist ground. Distrubution maps have been carefully updated – particularly in the light of human influence. The species descriptions are based on what you can see in the live animal and colour has been used with caution. Where there are colour variations this is noted in the text. The book is illustrated throughout with beautiful water colour paintings of each species, as well as line drawings to show particular distinguishing features. There are also ful pages of line drawings that illustrate the species on each page in order to relate the animal’s sizes to each other and to a human figure or a hand. This is a wonderful book and will be a delight to use.
The developing internet Imagining Web 3.0. By Lee-Roy Chetty. (Cape Town. Big Red. 2012.) The origins of the internet date back to 1968, when the Advanced Research Projects Agency (ARPA), in the US Department of Defence, started a project that led to the development of the internet. ARPANET was the outcome and was launched on 1 October 1969. This was the ‘first transcontinental high-speed computer network’ and eventually went on to link universities, defence contractors and research laboratories. This was the most important step in the birth of the internet that we know today – and revolutionised communication between researchers. What we now understand as ‘the internet’ has taken only 18 years to develop – and during this time it has evolved into three version. Web 1.0 was the information web – full of static content, essentially an extension of off-line media, such as print or television. The next evolution was Web 2.0 – the social web in which users communicate, contribute and collaborate. Social networking, live chat, folksonomies, mash-ups, virtual worlds and mobile media are
52 Quest 8(1) 2012
all part of Web 2.0. Users of the internet are no longer passive content consumers but now actively provide content and information. So what is Web 3.0? Of course no-one knows for sure, but Lee-Roy Chetty has carefully researched and analysed trends in the internet that can broadly point towards the changes that will take place – and in some cases are already taking place. Web 3.0 is also called the Semantic Web, which, through intelligent software, will allow the internet to have the power to learn, intuit and decide, giving the information that is found on the internet a well-defined meaning. An excellent read.
Grasslands Guide to Grasses of Southern Africa. By Frits van Oudtshoorn. (Pretoria. Briza Publications. 2012.) Southern Africa has a wide variety of grasses and some of the best grazing. Many of our grasses are used as cultivated pastures all over the world. We also have some of the best thatching grasses and many other southern African grasses are used as lawns and ornamental grasses. But why a guide to grasses? The author explains that there are three reasons that grasses are important – as a source of food, for their important ecological role and because they are highly effective in protecting and stabilising topsoil. Grasses were the first food plants that were cultivated by humans. Most animals are directly or indirectly dependent on grasses. This book will be interesting to anyone who enjoys the natural world around us. The book is aimed at the general naturalist, but is comprehensive enough to provide the specialist with important information. And it is a practical guide to use in the field (if in a slightly large format for a field guide). It is practical and easy to use, whith colour photographs for each species, a key to identify the various grasses, discussion of the diagnostic features of each grass and other related grasses and the distribution of each species in southern Africa. The photographs are carefully chosen to make the sometimes difficult job of identifying grasses easier. The photographs show colour and also the growth form of the grass. Each species starts with the diagnostic features of the species – usually illustrated by line drawings or photographs. The introductory chapters cover areas such as the grains, grazing, cultivation, grasses and veld fires and grasses and veld restoration. There is also a chapter on grasses in plant sucession – which would be useful to illustrate this concept in population ecology. A wonderful book to have in the classroom to illustrate practical ecology.
Q Books Are we alone? The Living Cosmos. By Chris Impey. New York. Cambridge University Press. 2011.) The Living Cosmos is a book about astrobiology – aimed at people with no background in the subject – and is a survey of the state of the art in the subject. It starts with the history of how we have come to know our place in the universe – from ancient Greece to the start of modern cosmology and the emergence of astrobiology. Impey goes on to discuss life’s origins – cosmic chemistry, deep time and the first traces of life and how it started, going on to discuss life at extremes on Earth and then how life evolved through the ages on the planet and what we can learn from our own world. Next is a discussion of the prospects of life elsewhere in the Solar System, followed by exciting new research on distant planets and the potential for intelligent life elsewhere in the universe. So, are we alone? We now know that chemistry is universal and that there are plenty of distant worlds. We also know that every part of Earth, even the most extreme environments, are full of life. So it is unlikely that the Earth is the only time and place in the whole cosmos where biology led to intelligence and technology. It is also unlikely that we are the only intelligence that has ventured into space and attempted communication between the stars. But we do not yet have an answer to the question. Indeed, we cannot yet fully understand the story of our own planet. However, Impey provides a wonderful exploration of how we are attempting to answer the question.
Fire and brimstone Eruptions that Shook the World. By Clive Oppenheimer. (New York. Cambridge Unversity Press. 2011.) Clive Oppenheimer is a volcanologist – one of those crazy people who get incredibly close to the edges of live volcanoes and don’t flee eruptions like normal people do! Although this is a relatively technical book, it will be fascinating reading for anyone who is interested in the structure and formation of our planet. Volcanology is a branch of the earth sciences and deals not only with what modern volcanoes do, but with how they formed and what happened in our distant past, when the Earth was forming. The volcanoes that erupted in the Earth’s distant past were much hotter than their modern equivalents. Most volcanoes are found along the oceanic ridges formed when tectonic plates separate from each other – and these are deep and distant phenomena that are never seen erupting. Other volcanoes are found in the middle of nowhere, far from tectonic plate boundaries – Hawai is probably the best example. Still other volcanoes are formed along great tears in continents, such as the East African Rift Valley. The book starts with how volcanoes work – an excellent overview of the formation of volcanoes and how they erupt. The discussion continues with eruption styles, hazards and impacts on the ecosystem – and is followed by volcanoes and global climate
change. Then there is a chapter on forensic volcanology – something I bet you have never heard of. This deals with identifying potentially dangerous volcanoes and involves looking at the record of volcanism, which can be direct, as seen in the ash and pumice deposits in rock sequences and so on, or by examining their indirect effects on, for example, climate changes that are recorded in tree rings. Volcanoes have generated many myths through the ages – as is the case with any frightening phenomena that is not understood. Because eruptions are rare, these myths are useful to volcanologists because they provide another window into the past. A particularly interesting aspect of the book is the way that the author links some of the major volcanic eruptions of the past with history and pre-history. This is very interesting book, giving a wonderful overview of the history of volcanoes and their effect on the world and its people.
Primary produces Reaching for the Sun: How Plants Work. By John King. (New York. Cambridge Unversity Press. 2011.) Without plants there would not be life. We all depend on plants for our food, either directly or indirectly. This book, although written by a plant physiologist, is aimed at the lay person. King explains how plants function, how they derive energy, how they grow and develop and how they die. There is also a section dealing with plants and the environment, exploring how problems created by human activities, such as climate change, land, water and air pollution and the increasing acidity of the oceans, are having an affect on the lives of plants. The style is very readable and would provide an excellent extension to the Life Sciences curriculum as well as an interesting approach for anyone who loves learning about nature and there are excellent chapters on plant defences and plant nutrition, which are often poorly covered in botany textbooks.
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Diary of events Q Shows and exhibitions Iziko Museum, Cape Town The World’s Oldest Chemistry Set? New Discoveries from Blombos Cave • Location: South African Museum8 • From: October 13, 2011 at 12:00am • To: October 13, 2014 at 12:00pm ‘What makes us human?’ This topical question receives some answer in the form of two unique 100 000-year-old ochre preparing kits from Blombos Cave, South Africa. This remarkable archaeological discovery is the oldest known evidence of the human use of containers, and also the oldest known evidence of people practicing chemistry. Enquiries: Sven Ouzman Tel. 021 481 3883 • email firstname.lastname@example.org
For the March/April school holidays! Silly Solly and the Shooting Stars
playful introduction to astronomy especially for the under 10s. Just right for inquiring young minds. 14 April – 17 June Saturday – 12:00 Sunday – 12:00 Plus 27 April – 12:00 Especially for children aged 5 – 10. For the June/July school holidays!
Davy and the Dinosaur Davy Dragon finds a newly hatched creature that he thinks is a baby ostrich. But is it? Davy and his grandfather magically take the creature back to its mother. Join us and discover what kind of creature Davy found and what it has to do with the Milky Way!
Cape of Stars Not only is Table Mountain known for its unique geology and flora, but within its shadows significant pioneering studies have shed light on the nature of the night sky above. 26 March – 9 April Monday to Friday – 13:00
Solly Snail wants to be chosen for his garden's soccer team and thinks up ways to become a speedier snail, so that he will be chosen. He decides to ask a shooting star to help him, but does his plan work and will he be chosen for his garden's soccer team? Join him on his quest and find out for yourself! 24 March – 9 April Monday to Friday: 11:00, 12:00 & 15:00 Saturday – 12:00 & 15:30 Sunday – 12:00 & 15:30 For children aged 5-12
Davy Dragon’s Guide to the Night Sky
The Cape Bird Club
Come and join Davy Dragon while he learns all about the sky above so that he can fulfil his dream of becoming the world’s best flying dragon! This is a
This show explores the fascinating discoveries made by the Hubble Space Telescope, highlighting its spectacular observations and demystifying the processes that shape our cosmos. 14 April – 17 June Monday to Friday – 14:00 (excluding 1, 7 May & 4 June) Tuesday evening – 20:00 (& sky talk) (excluding 1 May) Saturday – 14:30 Sunday – 14:30
Talks, outings and events Evening meetings are on the 2nd Thursday of every month at 20h00, we meet at The Nassau Centre, Groote Schuur High School, Palmyra Road, Newlands. Visitors and non-members, are very
welcome, tea and biscuits are served afterwards. Thurs 12 April A selection of birds in India by Cathy Jenkins. • Thurs 10 May What a way to spend Christmas by Dr Dave Whitelaw.• Sat 7 April Rondevlei Leader: Merle Chalton on 021 696 8951 • Wed 11 April Tokai Forest and Arboretum Co-ordinator: Frank Hallett on 021 685 7465 • Sun 22 April Harold Porter Botanical Gardens, Betty's Bay and Rooisand Nature Reserve Leader: Jan Hofmeyr 021 686 3047 and Merry Berrisford 082 272 9314 Co-ordinator: Frank Hallett on 021 685 7465 • Sat 5 May Rondevlei Leader: Merle Chalton on 021 696 8951 • Tues 8 May Intaka Island (Blouvlei – Century City) Leader: One of the Intaka Island Bird Guides. Co-ordinator: Frank Hallett on 021 685 7465 • Sun 20 May Diemersfontein Farm, Wellington Leader: Peter Nupen 021 930 4244 Co-ordinator: Frank Hallett on 021 685 7465
Diarise Earth Day – 22 April 2012 Earth Day is a day that is intended to inspire awareness and appreciation for the Earth's natural environment. The name and concept of Earth Day was allegedly pioneered by John McConnell in 1969 at a UNESCO Conference in San Francisco. The first Proclamation of Earth Day was by San Francisco, the City of Saint Francis, patron saint of ecology. Earth Day was first observed in San Francisco and other cities on March 21, 1970, the first day of Spring. Numerous communities celebrate Earth Week, an entire week of activities focused on environmental issues. In 2009, the United Nations designated April
WALTER SISULU UNIVERSITY Walter Sisulu University offers fully accredited diplomas, degrees and postgraduate studies in a wide range of science programmes in its Faculty of Health Sciences and Faculty of Science, Engineering and Technology: Faculty of Health Sciences: MBChB; B Cur (Basic); Bachelor of Medical Sciences (Physiology, Biochemistry or Microbiology); Bachelor of Medical Clinical Practice; Bachelor of Social Work; Bachelor of Science in Health Promotion. Faculty of Science, Engineering and Technology: National Diplomas, degrees and postgraduate studies in Applied and Environmental Sciences; Information Technology; Computer Science; Analytical Chemistry; Botany; Physics; Zoology; Engineering – Civil, Electrical, Mechanical; Construction Management and Quantity Surveying; Food and Consumer Science; Applied Mathematics and Statistics as well as technological programmes in Fashion and Art. For affordable, fully accredited, quality higher education contact us today and apply before 31 October. Faculty of Health Sciences: Tel: 047 502 2111/2844 (Mthatha) Faculty of Science, Engineering and Technology: Mrs GK Lindani-Skiti, Tel: 043 702 9257, Fax: 043 702 9275, E-mail: email@example.com Offered at Buffalo City (East London), Butterworth and Mthatha Campuses.
www.wsu.ac.za 54 Quest 8(1) 2012
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Q Back page science Oldest recorded supernova This image combines data from four space telescopes to create a multi-wavelength view of all that remains of RCW 86, the oldest documented example of a supernova. Chinese astronomers witnessed the event in 185 AD, documenting a mysterious ‘guest star’ that remained in the sky for eight months. X-ray images from NASA's Chandra X-ray Observatory and the European Space Agency's XMM-Newton Observatory show the interstellar gas that has been heated to millions of degrees by the passage of the shock wave from the supernova. So how did it grow so large in such a short amount of time? By blowing away wind prior to exploding, the white dwarf was able to clear out a huge ‘cavity,’ a region of very low density surrounding the system. The explosion into this cavity was able to expand much faster than it otherwise would have. This is the first time that this type of cavity has been seen around a white dwarf system prior to explosion. RCW 86 is about 8 000 light-years away and is about 85 light-years in diameter. Source: NASA
Previous research had found that anole lizards living in forests had longer hind limbs than those found in scrub habitat. Lizards with longer limbs can run faster on the broad perches available in forests, while short-limbed lizards are more adept at moving on the narrower perches found in lower vegetation. Because the structure of the vegetation on the islands differed from that of the source island, the scientists predicted that natural selection would lead the lizards to develop shorter limbs. ‘Over the next four years, the lizards on all the islands experienced a decrease in leg length that is attributable to natural selection,’ Kolbe explained. ‘But those that started out with the longest hind limbs still had the longest hind limbs.’ Source: National Science Foundation Friend mouse leukaemia virus (yellow) budding from infected T-lymphocyte (blue). Image: Elizabeth Fischer and Kim Hasenkrug, NIH
A look at liquid batteries
A male brown anole lizard (Anolis sagrei) displays its eye-catching dewlap. Image: Neil Losin
Why bad immunity genes survive
The oldest recorded supernova.
Image: X-ray: NASA/CXC/
SAO & ESA; Infared: NASA/JPL-Caltech/B. Williams [NCSU]
Castaway lizards offer a new look at evolutionary processes Biologists who released lizards on tiny uninhabited islands in the Bahamas have uncovered a seldom-observed interaction between evolutionary processes. Jason Kolbe, a biologist at the University of Rhode Island (URI) – along with colleagues at Duke University, Harvard University and the University of California, Davis – found that the lizards' genetic and morphological (form and structural) traits were determined by both natural selection and a phenomenon called the founder effect. This is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population.
Biologists have found new evidence for why mice, humans and other vertebrates carry thousands of varieties of genes to make immunesystem proteins called major histocompatibility complex (MHCs) – even though some of those genes make vertebrates susceptible to infections and to autoimmune diseases. MHC proteins are found on the surfaces of most cells in vertebrates. They distinguish proteins like themselves from foreign proteins, and trigger an immune response against these foreign invaders. MHCs recognise invading germs, reject or accept transplanted organs and play a role in helping vertebrates smell compatible mates. ‘Results of this study explain why there are so many versions of the MHC genes, and why the ones that cause susceptibility to diseases are being maintained and not eliminated,’ says biologist Wayne Potts of the University of Utah. ‘They are involved in a never-ending "arms race" that causes them, at any point in time, to be good against some infections but bad against other infections and autoimmune diseases.’ Source: National Science Foundation
The biggest drawback to many real or proposed sources of clean, renewable energy (solar, wind) is that the wind doesn’t always blow, and the sun doesn’t always shine, so the power they produce may not be available at the times it’s needed. New results from an ongoing research programme at MIT show a promising technology that could provide that long-sought way of levelling the load. The system uses hightemperature batteries whose liquid components, like some novelty cocktails, naturally settle into distinct layers because of their different densities. The three molten materials form the positive and negative poles of the battery, as well as a layer of electrolyte – a material that charged particles cross through as the battery is being charged or discharged – in between. All three layers are composed of materials that are abundant and inexpensive, explains Donald Sadoway, the John F Elliott Professor of Materials Chemistry at MIT and the senior author of the new paper. One such combination is magnesium for the negative electrode (top layer), a salt mixture containing magnesium chloride for the electrolyte (middle layer) and antimony for the positive electrode (bottom layer). The system would operate at a temperature of 700 °C. The battery delivers current as magnesium atoms lose two electrons, becoming magnesium ions that migrate through the electrolyte to the other electrode. There, they re-acquire two electrons and revert to ordinary magnesium atoms, which form an alloy with the antimony. To recharge, the battery is connected to a source of electricity, which drives magnesium out of the alloy and across the electrolyte, where it then rejoins the negative electrode. Source: MIT
MIND-BOGGLING MATHS PUZZLE FOR Q uest READERS Q uest Maths Puzzle no. 20
Win a prize!
Find three whole, positive numbers that have the same answer when multiplied together as when added together. i.e. a x b x c = e and a + b + c = e Note: e is the same in both equations.
Send us your answer (fax, e-mail or snail-mail) together with your name and contact details by 15:00 on Friday, 18 May 2012. The first correct entry that we open will be the lucky winner. We’ll send you a cool Truly Scientific calculator! Mark your answer ‘Quest Maths Puzzle no. 20’ and send it to: Quest Maths Puzzle, Living Maths, P.O. Box 478, Green Point 8051. Fax: 0866 710 953. E-mail: firstname.lastname@example.org. For more on Living Maths, phone (083) 308 3883 and visit www.livingmaths.com.
Answer to Maths Puzzle no. 19: 5 in the 1st phase, you get 2/3 ; 20/6 and 56/9 respectively. In the second 14 5 phase when you multiply 2/3 by 20/6 and then multiply 9/56 (reciprocal) = 14 The winner of Maths Puzzle no. 19 was Evidence Mack, Sasolburg, Free State.
Quest 8(1) 2012 57
kids love chemistry Getting the next generations excited about chemistry is important for humankind’s future. That’s why we’ve created “Kids’ Lab” in 15 countries, where the young ones can learn about chemistry and science in a fun, hands-on way. Little students and test tubes finally getting along? At BASF, we create chemistry. www.basf.com/chemistry www.basf.co.za Tel: +27 11 203 2400
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