THE SOLAR SYSTEM AND THE EARTH

THE UNIVERSE, THE SOLAR SYSTEM AND THE EARTH. 1.- THE UNIVERSE: The universe has got three components: the matter that form heavenly bodies, the energy that make possible interactions between them, and space-time dimension where they are.

Nowadays, we know that the universe is in a expansion process, and all it started with ‘The Big Bang’,that was a huge explosion about 15,000 million years ago. This theory was developed by Edwin P. Hubble, an American astronomer.

After this explosion, million of stars were formed because of energy and forces between matter. Later these starts joined into galaxies. One of these galaxies is the ‘Milky Way’, where we found one star called ‘The Sun’, and around it, there are some heavenly bodies, one of them is our planet: ‘The Earth’.

(the Milky Way)

2.- THE SOLAR SYSTEM: The Solar system is formed by some heavenly bodies: the Sun, some planets and their satellites, comets and asteroids.

The Sun is a yellow star of medium size. It’s formed by hydrogen and helium. There are continuously atomic explosions that release lot of energy. Its surface is more than 5,000º C, so this is the reason because of we get heat from the sun.

There are some planets revolving around the Sun. They have circular or elliptical trajectories called ‘orbits’. Most of the planets have satellites revolving around them (like the Moon is revolving around the Earth).

There are 8 planets in our Solar System: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune (Nowadays Pluto is not considered a planet)

The following table compares major features of the Sun and planets, and many planetary characteristics to Earth's own: Orbital Rotational Orbital Mean Surface Distance Mass Diameter Period Period Density Gravity Moons (AU) (earths) (earths) (days) (years) (earths) (earths) 0.0 330,000 109.2 25.4 ...

1.42 28 ...

Sol 0.06 0.38 59 0.24 0.98 0.38 0 Mercury 0.4 0.7 0.81 0.95 243 0.62 0.95 0.90 0 Venus 1.0 1.00 1.00 1.00 1.0 1.00 1.00 1 Earth 1.5 0.11 0.53 1.03 1.9 0.71 0.38 2 Mars 2.8 0.00015 0.07 0.38 4.6 0.38 0.03 0 (Ceres*) 5.2 317.8 11.2 0.42 11.9 0.24 2.34 63 Jupiter 9.5 95.2 9.4 0.44 29.4 0.12 1.16 60 Saturn 19.2 14.5 4.0 0.72 83.7 0.23 1.15 27 Uranus 17.2 3.9 0.67 163.7 0.30 1.19 13 Neptune 30.1 0.002 0.18 6.40 248.0 0.37 0.04 3 (Pluto*) 39.4 67.7 0.002?

0.18 ~8 557 0.42 ?

1 (Eris*) (*Now defined as a "dwarf planet.")

The four rocky planets at the center of the solar system Mercury, Venus, Earth and Mars, are known as the inner planets.

Jupiter, Saturn, Uranus and Neptune all composed primarily of gas and are known as the outer planets.

Definitions: 1. A star is a massive ball of plasma (very hot gas) held together by gravity. It radiates because of the nuclear reactions inside it.

2. A planet is a celestial body orbiting a star, that is massive enough to be rounded by its own gravity.

3. A natural satellite or moon is a celestial body that orbits a planet.

4. Asteroids are small celestial bodies that revolve around the sun, with orbits lying chiefly between Mars and Jupiter.

5. A comet is a celestial body of ice and dust that periodically come into the center of the solar system from its outer orbit. When comets get close enough to the Sun, heat makes them start to evaporate.

3.- THE EARTH, OUR PLANET. Earth, our home planet, the third planet from the Sun, it is the largest of the inner planets. Because of its physical and chemical conditions and the distance from the Sun, it is the only planet known to support life and to have liquid water at the surface. Earth has an atmosphere and magnetic field, both of which are necessary for sustaining life on Earth.

It was formed 4 million years ago because of particles began to stick together and form clumps. Some clumps got bigger and bigger cause particles and other clumps or meteorites stuck to them, and formed our planet (the Moon and the rest of planets).

2.1.- Parts of the Earth:

.- Geosphere: is the solid part of the Earth which consist mostly of rock. These rocks are formed of different minerals like quartz, feldspar, mica, calcite… It has got a sphere shape and a radio of 6.378 km.

The Geosphere has got three layers: a.- Crust: from 5 to 70 km thick. It forms the relief of continents and oceans. b.- Mantle: it’s about 3,000km thick. It’s a highly viscous layer between the crust and the core. c.- Core: it has got a radio about 3,500 km, and it’s formed by liquid rock because of the high pressure and temperature (more than 5,000º C). (It’s divided in outer core and inner core)

.- The BIOSPHERE is the zone of life on Earth, the global sum of all ecosystems. We can divide it in: a.- Lithosphere (The outer part of the earth, consisting of the crust and upper mantle). It forms the continents, mountains, plains… b.- Hydrosphere the mass of water under and on the surface of the planet (oceans, rivers, lakes, ice…).

There are two kinds of water: salt water (94%) and fresh water (6%). c.- Atmosphere: are the gases surrounding the planet. The atmosphere protects life on Earth by absorbing radiations, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night.

The atmosphere has got some layers: the most important for us is the troposphere is the lowest portion of Earth’s atmosphere, where life is possible, and there are atmospheric phenomenons. There are more layers like stratosphere, ionosphere…

4.- EARTH’S MOVEMENTS:

Our planet has got two movements:

.- Rotation is the movement that the Earth describes spinning around an imaginary axis, eastbound. It spends 24 hours to complete a full spin. The rotary motion produces a succession of day and night, as well as the time difference between some areas of the Earth. .- Translation is the movement that the Earth describes around the Sun. It describes an elliptical orbit, and spends 365 days and 6 hours. Those 6 hours which are accumulated each year, after 4 years, they are 24 (one day). Each four years there is one that has 366 days, called leap year. http://www.claseshistoria.com/bilingue/1eso/earthplanet/imagenes/translationmovement2.swf

The translation movement causes the four seasons: Spring, Summer, Autumn and Winter. Another effect of the inclination of the axis of the Earth on the ecliptic is the different duration of the day and the night, as Summer or Winter.

5.- THE REPRESENTATION OF THE EARTH Globes are three-dimensional models that represent the Earth, but they have a problem that makes them less useful than maps. Globes have drawings of the meridians and parallels, and an inclined axis is often inserted to symbolize the inclination of the Earth with respect to the sun.

A map projection is the method to represent the Earth's surface on a plane. It translates meridians and parallels to a flat surface.

Parallels North hemisphere

Equator South hemisphere

Meridians .- Parallels are imaginary circles (360ยบ) perpendicular to the axis of the Earth. They are parallel to each other. The Equator is the largest parallel and it divides the Earth into two hemispheres: North and South.

Latitude is the distance (in degrees, minutes and seconds), between any point on the Earth and the Ecuador.

There are Northward and Southward latitude. .- Meridians are imaginary maximum semicircles (180ยบ), from the North pole to South pole. The meridian of reference (0ยบ degrees) is Greenwich, the name of the astronomical observatory near London.

Longitude: the distance from any point to the meridian 0 (Greenwich).

There are East longitude and West longitude.

Parallels: Latitude (northward, southward)

Meridians: Longitude (East, West longitude)

GLOSARY-VOCABULARY: The matter: la materia ‘Milky Way’: Vía Láctea

to develop: desarrollar

huge explosion: enorme explosión

heavenly bodies: cuerpos celestas hydrogen and helium: hidrógeno y helio

Surface: superficie

to release energy: liberar energia

elliptical trajectories: trayectorias elípticas

Orbit: órbita

Heat: calor

Nowadays: en nuestros días, ahora

to revolve: girar

features: cifras, numerous

the following table: la siguiente tabla

dwarf planet: planeta enano inner planets: planetas interiores.

Outer planets: planteas exteriores

rocky planet: planeta de roca massive ball: enorme bola

held (past of ‘to hold’): sujetar, sostener

to orbit: girar, hacer órbitas chiefly, mostly: principalmente, sobre todo massive enough to be rounded by its own gravity: suficientemente grande para redondearse por su propia gravedad. a celestial body of ice and dust: cuerpo celeste de hielo y polvo.

close enough: suficientemente cerca de

to support / sustain life: sostener la vida

magnetic field: campo magnético

particles began to stick together and form clumps: partículas empezaron a pegarse juntas y a formar ‘terrones’ sphere shape: forma esférica

quartz, feldspar, mica, calcite: cuarzo, feldespato, mica, calcita

layer: capa, estrato

crust: corteza

mantle: manto

core: núcleo

liquid rock: roca líquida.

greenhouse effect: efecto invernadero

to spin: girar

atmospheric phenomenons: fenómenos atmosféricos (lluvia, viento, nieve…)

eastbound: hacia el Este

leap year: año bisiesto

axis: eje

Northward latitude: latitude Norte Southward latitude: latitude Sur

globe: globo terráqueo East longitude: longitude Este.

LINKS TO LEARN MORE (BIBLIOGRAPHY and ACKNOWLEDGMENTS): http://en.wikipedia.org/wiki/Natural_satellite The Universe: http://www.windows2universe.org/our_solar_system/solar_system.html the Earth:

http://www.claseshistoria.com/bilingue/1eso/earthplanet/movements.html