Field Guide to the Sky by Trishta Blizzard

Field Guide to the Sky

By Trishta Blizzard

Background image: https://www.pexels.com/photo/blue-universe-956981/.

1

Introduction This is a compilation of what I have learned in Astronomy 103 through the University of Alaska Southeast. During this time I compiled a book of what I have learned from the topics about constellations, planets, moons, the Earth and Sun, as well as comets, asteroids, and dwarf planets. Please enjoy my book, I hope you find these details of each topic as interesting as I did.

Background image: https://www.pexels.com/photo/blue-universe-956981/.

2

Table of contents Seasonal Constellations Sun Moon Earth Mercury Venus Mars Jupiter Saturn

Pg. 4 Pg. 11 Pg. 15 Pg. 19 Pg. 23 Pg. 27 Pg. 31 Pg. 35 Pg. 37

Uranus Dwarf Planets: Ceres Comet ’Oumuamua Asteroid Bennu

Pg. 39 Pg. 40 Pg. 43 Pg. 45

3

Seasonal Constellations

By Trishta Blizzard

Background image: https://www.pexels.com/photo/blue-universe-956981/.

4

Introduction • Asterism:

Is a prominent pattern of stars, typically having a popular name but smaller than a constellation. Visually obvious collection of stars and lines used to connect them. Asterism do not officially recognized boundaries.

• Constellation:

Is an officially recognized area of the sky in which a group of stars forms an imaginary pattern or outline, typically representing an animal, mythological person or creature, a god, or an inanimate object.

I picked the constellations Pictor, Pyxis, Boötes, and Aquila because I have never heard of them before and I wanted to learn about new and unfamiliar constellations.

Background image: https://www.pexels.com/photo/blue-universe-956981/.

5

Pictor

Official name: Equuleus Pictoris Meaning: The painter’s easel Myth/Story/History: There is no myth associated with Pictor, however, it was first introduced by Nicolas Louis de Lacaille in 1756 as le Chavalet et la Palette, which means “the easel and palette”. He later named the constellation Equuleus Pictoris on his planisphere. Later an English astronomer Francis Baily shortened the name to Pictor.

How to locate: Pictor is located in the first quadrant of the southern hemisphere and can be seen at latitudes between +26° and -90°.

Special stars or galaxies in the constellation: The brightest star in the constellation is Alpha Pictoris with an apparent magnitude of 3.30

Image: https://en.wikipedia.org/wiki/Pictor 6 Background image: https://www.pexels.com/photo/blue-universe-956981/.

Pyxis

Official Name: Pyxis Nautica Meaning: Mariner’s Compass Myth/Story/History: French astronomer Nicolas Louis de Lacaille created the constellation in 1751-52. He originally named it La Boussole and later Latinized it to Pixis Nautica. The constellation represents the magnetic compass used by navigators and seaman.

How to locate: Pyxis is located in the second quadrant of the southern hemisphere and can be seen at latitudes between +50° and -90°.

Special stars or galaxies in the constellation: The brightest star in the constellation is Alpha Pyxidis, with an apparent magnitude of 3.68.

Background image: https://www.pexels.com/photo/blue-universe-956981/.

Image: https://www.allthesky.com/constellations/visualconstellations.html

7

• Meaning: Oxdriver or Herdsman

Boötes

• Myth/Story: According to myth, Boötes is credited for inventing the plough, which prompted the goddess Ceres – a goddess of agriculture, grain crops, fertility and motherly love – to place him in the heavens.

There is another version where this constellation represents a form of Atlas, holding up the weight of the world as it turns on its axis. Most commonly, Boötes is taken to represent Arcas, the son of Zeus and Callisto. In this myth, Arcas was brought up by Callisto Father, the Arcadian King Lycaon. One day Lycaon decided to test Zeus by serving his own son as a meal. Zeus saw what Lycaon intended and transformed him into a wolf, killed his sons, and brought Arcas back to life. Having heard of his infidelity, Zeus’ wife Hera transforms Callisto into a bear.

The bear roams the woods for years until she finds her son. Arcas did not recognize his mother and began to chase her. To intervene Zeus placed them both in the sky, where Callisto became Ursa Major (The Big Dipper or Great Bear) and Arcas becomes Boötes.

• History or Discovery: In the second century CE, Greek-Egyptian astronomer Claudius Ptolemaeus was discovered and cataloged.

• How to locate: It is bordered by Canes Venatici, Coma Berenices, Corona Borealis, Draco, Hercules, Serpens Caput, Virgo and Ursa Major.

• Special stars or galaxies in the constellation: Boötes contains the third brightest star in the night sky, Arcturus, an important red giant star.

Photo retrieved from http://www.Universetoday.com Background image: https://www.pexels.com/photo/blue-universe-956981/.

8

Aquila • Meaning: The Eagle • Myth/Story: In Greek mythology, Aquila is identified as the eagle that carried Zeus’ thunderbolts. In another myth, the eagle is found guarding the arrow of Eros, which hit Zeus and made him love-struck. In another story, Aquila is Aphrodite disguised as an eagle, pretending to pursue Zeus in the form of a swan, so that Zeus’ love interest Nemesis will give him shelter. Later, Zeus placed the images of the eagle and the swan in the sky to commemorate the event.

• History or Discovery: First cataloged by the Greek astronomer Ptolemy in the 2nd Century.

• How to locate: Is in the fourth quadrant of the northern hemisphere and can be seen at latitudes between +90° and 75°.

• Special stars or galaxies in the constellation: Aquila has three stars brighter than magnitude 3.00 and two stars located within 10 parsecs (32.6 light years) of Earth.

Photo from https://en.wikipedia.org/wiki/Aquila_(constellation) Background image: https://www.pexels.com/photo/blue-universe-956981/.

9

References Constellation Guide. (2020). Aquila Constellation. Retrieved from: https://www.constellation-guide.com/constellation-list/aquilaconstellation/ Constellation Guide. (2020). Pictor Constellation. Retrieved from: https://www.constellation-guide.com/constellation-list/pictorconstellation/ Constellation Guide. (2020). Pyxis Constellation. Retrieved from: https://www.constellation-guide.com/constellation-list/pyxisconstellation/ Universetoday.com (n.d.). The constellation bootes. Retrieved from: https://www.universetoday.com/19636/bootes/ Background image: https://www.pexels.com/photo/blue-universe-956981/.

10

Official Name: SOL Commonly known as: Sun Sol is the Roman equivalent of the Greek sun god Helios

Background: https://newslanded.com/2020/01/31/sun-detailed-image-nsf/

11

• Myth: For the Aztecs, who lived in central Mexico, Tonatiuh was a Sun god. Aztecs believed that four suns had been created in four previous ages. They believed that each sun had died at the end of each cosmic era. Tonatiuh was the fifth sun and the present era is still his. The carvings in this sunstone represent the four cycles of creation and destruction in the Aztec creation story. The skull at the center depicts the god Tonatiuh.

Background: https://newslanded.com/2020/01/31/sun-detailed-image-nsf/

12

The SUN’s properties: The sun is primarily made of the elements of hydrogen and helium. The sun includes the same elements of Earth but dramatically smaller measurements. The sun has layers surrounding a dense core where all of its energy emits from and the temperature is approximately 15 million k. The layer above its core is called the Radiative Zone and is the primary way energy travels across the sun surface.

The Convection Zone is outermost layer of the solar interior. The light generated in the core of the sun travels through the Radiative Zone and through giant convection cells of the Convection Zone. The next layer is the Photosphere and is the visible part of the sun where the sun takes on an opaque color. The energy moving through the layers of the sun now move through the Photosphere in the form of photons.

There is less density and the photons travel easier on to the Chromosphere, which is the sun’s outer layer.

Heat moving through the Chromosphere passes through the Transition Region onto the Corona of the sun.

The Chromosphere and Corona are transparent. The light being emitted from the Photosphere can make the outer layers faint light harder to see. The Corona’s gases are so hot it produces solar winds and move so fast they can’t be held back by the solar gravity and extends far out into space. As part of the Magnetosphere, there are magnetic field lines, which extend out into space through coronal holes rather than looping back into the sun.

One of the latest missions to study the sun is a collaboration between European Space Agency and NASA launching the Solar Orbiter on February 10, 2020. The mission is expected to collect the first images of the sun’s polar regions!

Background: https://newslanded.com/2020/01/31/sun-detailed-image-nsf/

13

References Fraknoi, A., Morrison, D., Wolff, S. C. (2018). OpenStax Astronomy. Creative Commons Attribution National Earth Science Teacher Association. (2010). Myths about Sun. Window2universe.org. https://www.windows2universe.org/mythology/planets/sun.html Thompson, A. (2020, February 10). Solar Orbiter Launches on a Mission to study the Sun’s Poles.

Space.com. https://www.scientificamerican.com/article/solar-orbiter-launches-on-a-mission-tostudy-the-suns-poles/

Background: https://newslanded.com/2020/01/31/sun-detailed-image-nsf/

14

The Moon Official Latin name: Luna Official Greek name: Selene Official Old English name: Mona

15

Myth about the Moon: Selene was a Titan goddess in Greek mythology, daughter of the Titans Hyperion and Theia. She had two siblings, Helios and Eos. She was the goddess of the Moon, which she drove every night across the sky. She was depicted riding a sidesaddle on a horse or driving a chariot drawn by a pair of winged steeds. She was sometimes said to drive a team of oxen.

Image of Selene from theoi.com/Titan/Selene.htmlene.h 16

Physical properties of the Moon:

Mission to the Moon: The Moon’s mean radius is 1079.6 miles. The Moon The US Apollo program sent nine piloted is slightly more than ¼ the Earth’s size. The Moon is spacecrafts between 1968 and 1972, landing approximately 238, 855 miles away from Earth.

12 astronauts on its surface. The Apollo Craters are a major feature we can see on the Moon. missions accomplished three objectives, one These have been caused by impacts from meteors and to collect nearly 400 kilograms of samples exploding volcanoes on the Moon over millions of from the surface of the Moon. A second years.

The plains where the volcano’s erupted are called the objective to launch Lunar Surface Experiment Packages that operated long Lunar Maria. The Moon’s crust consists of silicate rock and is referred to as the Lunar Highlands. after astronauts departed. The last objective was to analyze the surface of the moon from satellite orbiting the Moon.

Background Images: https://www.goodnet.org/articles/healing-through-moon-phases

17

References Background image: https://theconversation.com/five-ethical-questions-for-how-we-chooseto-use-the-moon-116801 Fraknoi, A., Morrison, D. , Wolff, S. (2020). Astronomy. LumenLearning.com. Retreived from courses.lumenlearning.com/astronomy Greekmythology.com (2020, February 21). Selene. Greekmythology.com. https://www.greekmythology.com/titans/selene/selene.html Nasa space place. (2020, February 21). How far away is the Moon? https://spaceplace.nasa.gov/moon-distance/en/ Schneider, C. (2015, June 22). Why Doesn’t Our Moon Have a Name? mentalfloss.com. https://www.mentalfloss.com/article/64667/why-doesn’t-our-moon-have-name Sharp, T. (2017, October 17). How Big is the Moon? Space.com. https://www.space.com/18135-how-big-is-the-moon.html Theoi Project. (2017). Selene. Theoi.com. https://www.theoi.com/titan/selene.html

18

Official Name: EARTH Other names: Terra, which is Latin for earth or dirt.

Size: The radius of the Earth at the equator is 3,963 miles. Earth’s mass is 6.6 sextillion tons.

Earth is 91.979 million miles from the Sun Earth has a dense metallic core. If the core was not metallic the Earth wouldn’t have a magnetic field. There is an outer liquid core and a solid inner core. The Mantle and Outer Crust, which are both made of rock.

Earth’s atmosphere is a think blanket of gases and tiny particles that are called air. If we did not have an atmosphere, we would be a lifeless planet like the Moon.

Background image: https://quoteproverbs.com/earth/

19

Myth or Story: According to a North American Indian myth, before the Earth was fully formed there were two realmsthat of the sky and the lower world that contained only water and water creatures.

When a woman, known as the Sky Woman, fell from the cloud world, two swans came to her rescue. The two swans were not strong enough to support the woman and a creature known as Great Turtle offered to hold her. Other water creatures brought earth from the bottom of the sea to place on the back of the Great Turtle, forming the Earth we know today. Some Indians still refer to Earth today as Turtle Island.

Turtle Island from http://coursesite.uhcl.edu/HSH/Whitec/texts/Amerind/origins/AmindorsIroquois.htm

20

Mission to Study Earth: Nasa’s Mission to Study Earth’s Atmosphere lit up the sky above Marshall Islands over the dates June 9-21, 2019. The mission was intended to study the disturbances in the upper atmosphere, which interfere with communication and technology systems. The rockets form night-time white artificial clouds. The clouds were photographed, examining the movement of these clouds to measure the winds and energetic particles that are in motion in the upper atmosphere.

Background image: https://quoteproverbs.com/earth/

21

References Fraknoi, A., Morrison, D., Wolff, S. (2020). Astronomy. LumenLearning.com.

Retreived from courses.lumenlearning.com/astronomy Black, P. (2019, June 20). NASA Mission to Study Earth’s Atmosphere by Forming Artificial Night-time Clouds over Marshall Island. Nasa.gov. https://www.nasa.gov/wallops/2019/feature/nasa-mission-to-study-earth-satmosphere-by-forming-artificial-night-time-clouds-over Loc.gov. (n.d.) Exploring the Early Americans Heavens and Earth: Earth Iroquois Creation Myth. Loc.gov. https://www.loc.gov/exhibits/exploring-the-earlyamericas/interactives/heavens-and-earth/earth/artifact2-earth.html Sharp, T. (2017, September 15). How Big is Earth? Space.com. https://www.space.com/17638-how-big-is-Earth.htmls Quora.com. (2018, April 15). What is another name for Earth? Quora.com. Retrieved from quora.com/what-is-another-name-for-planet-Earth 22

MERCURY The planet closest to the Sun and the smallest planet

(Image: © NASA/JHUAPL/CIW) Retrieved from space.com

23

MERCURY’s distance from đ&#x;Œž Mercury has an oval-shaped orbit that is highly elliptical, which takes it as close to the Sun as 29 Million miles and as far away from the Sun as 43 Million miles.

MERCURY’s mass Mercury is continually shrinking because it has a cooling iron core. Its core is approximately 2,200 to 2,400 miles wide or about 75 % of the planet’s diameter. Its outer shell is only 300 to 400 miles thick.

MERCURY’s physical properties Because Mercury is always shrinking, its surface is crumpled and is tectonically active. It causes valleys and canyons, cliffs. Mercury is the second densest planet next to Earth. Mercury has a magnetic field, but it is stronger at its northern hemisphere and much less at the southern hemisphere. Mercury’s magnetic field is 1 % the strength of Earths and solar wind from the sun causes powerful magnetic tornadoes that channel the hot plasma of solar winds to Mercury’s surface.

(Image: Š NASA/JHUAPL/CIW) Retrieved from space.com

24

Mercury was the messenger-god of Jupiter, and was the god of games, of business, and of story telling. The planet Mercury was named after the Roman messenger god because it is the fastest moving around the Sun.

Image: Painting by Diego Velazquez (1570) entitles “Mercury and Argos�. Retrieved from window2universe.org

25

MERCURY MISSIONS The first spacecraft to visit Mercury was Mariner 10, which imaged about 45 % of the surface and detected its magnetic field.

NASA’s Messenger Orbiter was the second spacecraft to visit Mercury.

It was the first spacecraft to orbit Mercury but ran out of gas and ended up crashing to Mercury’s surface.

REFERENCES Choi, C. Q. (2017, October 14). Planet Mercury: Facts about the Planet Closest to the Sun. Space.com. https://www.space.com/36-mercurythe-suns-closest-planetary-neighbor.html 26

VENUS The hot, hellish & volcanic planet

Image: Venus. Retrieved from space.com 27

VENUS’s distance from the đ&#x;Œž is 67,237,910 miles.

VENUS’s physical properties The atmosphere of Venus is hellish, consisting mainly of carbon dioxide with clouds of sulfuric acid. The atmosphere is much heavier than Earths, so much so that large structures could float high above the planets surface. Venus’s surface is mostly basalt and very dry. Venus is the hottest planet in the solar system.

VENUS’s mass The interior of Venus is made of metallic iron core that is roughly 2,400 miles wide. Venus has a molten rocky mantle that is roughly 1,200 miles thick.

28

VENUS MYTHOLOGY Venus is the second planet from the Sun and is named after the Roman goddess of love and beauty and is the only planet named after a female.

It may have been named this because it shone the brightest among the five planets known to ancient astronomers.

In ancient times, Venus was often thought to be two different stars, the evening and morning star. In latin, they were known as Vesper and Lucifer. In Christian times, Lucifer, or “light-bringer,� became known as the name of Satan before his fall.

With conditions on Venus described as infernal-the ancient name for Venus-Lucifer-seems to fit.

29

REFERENCES Choi, C. Q. (2020, January 16). Venus: The hot, hellish & volcanic planet. Space.com. https://www.space.com/44-venus-second-planetfrom-the-sun-brightest-planet-in-solar-system.html

30

MARS The fourth planet from the Sun, the red planet

Image: Mars. Retrieved from popsci.com 31

MARS is 141,633,260 miles from the đ&#x;Œž MARS physical properties, Mars has a cold, thin atmosphere where liquid water can’t exist. This desert planet is half the diameter of Earth, it has the same amount of dry land. Mars has the largest volcanos in the solar system. The channels and valleys of Mars suggest that water flowed over the planet at one time and may still lie in cracks and pores underground. Mars has polar caps that appear to be vast deposits of finely layered stacks of water ice and dust. Mars atmosphere is carbon-dioxide-rich and almost 100 times less dense than Earth’s.

MARS mass Mars solid core is composed of iron, nickel and sulfur. The mantle is mostly peridotite, and probably largely made of volcanic rock basalt and some volcanic rock that contains more silica. The Martian core is between 1,800 and 2,400 miles diameter, the mantle is 900 to 1,200 miles wide and its crust about 30 miles thick.

32

MYTHS OF MARS Befitting the Red Planet’s bloody color, the Romans named it after their god of war. In truth, the Romans copied the ancient Greeks who also named the planet after their god of war, Ares. Other civilizations gave the planet names based on its color like the Egyptians who named it “Her Desher,” meaning the red one, while ancient Chinese astronomers dubbed it “the fire star”.

33

MISSION TO MARS Robotic spacecraft began to observe Mars in the 1960’s when the United States launched Mariner 4 in 1964 and Mariners 6 and 7 in 1969.

The missions revealed Mars to be a barren world, without signs of life.

In 1971, Mariner 9 orbited Mars and mapped 80% of the planet and discovered its volcanoes and canyons.

REFERENCES

Choi, C. Q. (2019, February 7). Mars: What We Know About the Red Planet.

Space.com. https://www.space.com/47-mars-the-red-planet-fourth-planet-fromthe-sun.html

34

Jupiter Jupiter is the fifth planet from the Sun and the largest planet of the solar system Since it is the fourth brightest object in the sky, Jupiter was observed since ancient times and thus no one can be credited for its discovery.

Since Jupiter has been observed by many cultures, they have all given it different names, but the Roman name remained used in the majority of cultures. Jupiter is named after the principal Roman god, the equivalent of the Greek god Zeus.

Background Image: https://www.universetoday.com/22710/jupiter-compared-to-earth/

35

Jupiter is 5.2 astronomical units away from the Sun, an average of 484 million miles.

Its radius is 43,440.7 miles, which is approximately 11 times wider than Earth.

Jupiter’s

This planet is similar to the Sun in that is is mostly composed of helium and hydrogen. Inside atmosphere the pressure and tempratures increases compressing hydrogen gas into liquid, which gives this planet the largest ocean in the solar system. The coloring of the planets cloud bands are layers of three different kinds clouds most likely of ammonia ice, ammonium hydrosulfide crystals, and lastly water ice and vapors.

To NASA surprise, discovered in 1979 Voyager 1 spacecraft,

Jupiter

Jupiter has rings. Data from the spacecraft

indicated that rings system may be formed by dust kicked up as interplanetary meteoroids smash into this giants small innermost moons.

Jupiter has 53 confirmed moons and 26 provisional moons awaiting confirmation.

References Nineplanet.org. (2020, March 6). Jupiter. Nineplanet.org. Retrieved from https://nineplanets.org/Jupiter/ Solarsystem.nasa.gov (2019, Dec. 18). Jupiter in depth. Solarsystem.nasa.gov. Retrieved from https://solarsystem.nasa.gov/planets/jupiter/in-depth/ 36

Saturn Saturn is the sixth planet from the Sun and the second largest planet in our solar system. This planet was named after the Roman god of agriculture. Saturn was also the Roman god of time. Additionally, Saturday is also named after the Roman god Saturn (Saturn’s day).

Image: https://solarsystem.nasa.gov/resources/210/saturn-approachingnorthern-summer/?category=planets_saturn

37

Saturn has a radius of 36, 183.7 and is 9 times wider than Earth. Saturn is 9.5 astronomical units from the Sun, which is approximately 886 million miles.

Just like Jupiter, Saturn is mostly made of hydrogen and helium. Its core is a dense, made of metals of iron and nickel, surrounded by rocky material. This planet does not have a true surface, it is mostly swirling gases and liquids deeper down.

Saturn has had few missions visit it. Pioneer 11 and Voyagers 1 and 2 flew by. Cassini orbited

Saturn 294 times from 2004 to 2017, which ended with a planned plunge into Saturn’s atmosphere to send data back until the last second. This last mission helped scientist to sample Saturn’s atmosphere for the first time.

References http://coolcosmos.ipac.caltech.edu/ask/115-How-did-Saturn-get-its-nameSolarsystem.nasa.gov (2019, Dec. 18). Saturn in depth. Solarsystem.nasa.gov. Retrieved from https://solarsystem.nasa.gov/planets/saturn/in-depth/ 38

Uranus

• This photo of the ice giant, Uranus, was take by the spacecraft Voyager 2 in 1986 • Uranus has 27 moons, which are named after characters of William Shakespeare and Alexander Pope • Most of the mass of Uranus is made of hot, dense fluid of “icy” materials – water, methane and ammonia all above a small rocky core • Uranus has a radius of 15,759.2 and is 4 times wider than Earth • Uranus is 19.8 astronomical units from the Sun, which is approximately 1.8 billion miles distance References https://solarsystem.nasa.gov/planets/uranus/in-depth/#size_and_distance_otp Image: https://solarsystem.nasa.gov/resources/599/uranus-as-seen-bynasas-voyager-2/?category=planets_uranus 39

The Dwarf Planet Ceres

2.8 ASTRONOMICAL UNITS OR AN AVERAGE OF 257 MILLION MILES FROM THE SUN RADIUS IS 296 MILES OR 1/13 THE RADIUS OF THE EARTH Image: Dwarf Planet Ceres https://solarsystem.nasa.gov/planets/dwarfplanets/ceres/overview/

40

Ceres physical properties • Ceres is covered in small craters. Ceres has been hit by many asteroids during its 4.5 billion years lifetime.

However, due to ice below the surface and ice volcanoes, it has smoothed over time and erased large craters.

• Ceres has a layered interior and like terrestrial planets like Mercury, Venus, Earth or Mars but is much less dense. The layers are less defined and probably has a solid core with a mantle made of water ice. Ceres is approximately 25% water.

• Ceres atmosphere is very thin and there is evidence it contains water vapor. The vapor may be produced by ice volcanoes or by ice near the surface, transforming into gas.

• Living things on Ceres, if any at all, would most likely be very small microbes like bacteria!

• Ceres is named for the Roman goddess of grain crops and harvest. The word cereal comes from the same name.

Image: Ceres, Internal structure (Artist Concept) https://solarsystem.nasa.gov/resources/1075/ceres-internalstructure-artists-concept/?category=planets/dwarf41 planets_ceres

Mission to Ceres In 2015, Dawn arrives at Ceres, marking the first time a spacecraft has orbited a dwarf planet. Dawn discovered that the inner solar system’s only dwarf planet was an ocean world where water and ammonia reacted with silicate rocks. As the ocean froze, salts and other telltale minerals concentrated into deposits that are now exposed in many locations across its surface. Dawn also found organics in several locations on Cere’s surface (NASA, n.p.).

Reference: https://www.nasa.gov/mission_pages/da wn/mission/index.html https://solarsystem.nasa.gov/planets/dwa rf-planets/ceres/in-depth/

Image: Ceres, Occator Crater, simulated perspective. http://solarsystem.nasa.gov/planets/dwarfplanets/ceres/overview/ 42

The Comet ’Oumuamua

The first known interstellar object to visit our solar system discovered October 19, 2017 through the Near-Earth Object Observations (NEOO) Program.

Name is Hawaiian for “a messenger from afar arriving first” Image: Artist’s concept of ‘Oumuamua. https://solarsystem.nasa.gov/asteroidscomets-and-meteors/comets/oumuamua/in-depth/

43

• 'Oumuamua is unique because it varies in brightness by factor of 10, there is no known comet in our solar system which widely varies like it.

• The varying brightness indicates an elongated object.

• It has a reddish color because of irradiation from cosmic rays over hundreds of millions of years.

• It is dense and composed of rock and possibly metals. It has no water or ice.

Reference https://solarsystem.nasa.gov/asteroids-comets-andmeteors/comets/oumuamua/in-depth/

44

The asteroid Bennu AKA101955 Bennu

Image: Asteroid Bennu. https://solarsystem.nasa.gov/asteroids-cometsand-meteors/asteroids/101955-bennu/overview/

45

An ancient relic of our solar system’s early days, Bennu has seen more than 4.5 billion years of history (solarsystem).

It is said that Bennu likely broke from a larger asteroid 700 million to 2 billion years ago.

Bennu was most likely formed in the main asteroid belt between Mars and Jupiter.

The ancient asteroid may contain organic molecules like those that were involved with the start of life on Earth.

Bennu’s density is low, which suggest it probably a collection of loose rocks, like a pile of rubble.

Bennu is 20 to 40 percent empty space inside.

Reference: https://solarsystem.nasa.gov/asteroids-cometsand-meteors/asteroids/101955-bennu/in-depth/ Image: https://solarsystem.nasa.gov/asteroids-cometsand-meteors/asteroids/101955-bennu/overview/

46