Download The universe - COLLEGE THEODORE DESPEYROUS

Geography : the universe / 4° SE / 2011-2012
The universe
The universe is everything that exists : you, me,
planet Earth, planets in the solar system, distant
stars and billions of galaxies.
Galaxies are enormous groups of stars, gas and
dust. They contain billions of stars. Astronomers
think there are about 125 billion galaxies in the
universe.
Our galaxy, the Milky Way, is a spiral galaxy.
It contains the solar system. Astronomers think
there are more than 200 billion stars in our galaxy.
The solar system is made up of the Sun, planets, dwarf planets, moons, space rocks
and comets. They all orbit the Sun.
Rock planets : Mercury, Venus, Earth and Mars are rock planets : they are solid.
Giant planets : Jupiter, Saturn, Uranus and Neptune are made of gas. They are not solid.
Dwarf planets : Eris, Pluto and Ceres are planets, but they are smaller than the rock
planets.
Moons : there are 160 moons in the Solar system. Earth has one moon.
The Sun is not a planet, it is a star. It is a huge ball of gas. It is very big and very bright.
Geography : the universe / 4° SE / 2011-2012
Glossary
Try to match each word in the list with its correct definition. The first one (asteroid)
has been done for you.
asteroid / astronaut / astronomer / comet / dwarf planet / galaxy / moon / planet / solar
system / star / supergiant / universe
Asteroid
A lump of space rock orbiting the Sun
A round ball of rock (or rock and ice) orbiting
the Sun. It is smaller than a planet.
The Sun and everything that orbits around it
Everything that exists, existed, and will exist
A person who travels into space
A person who studies the stars, planets and
space
A large ball made of rock, metal, gas and
liquid that orbits the Sun (or another star)
An enormous group of stars, gas and dust
A lump of snow, ice and dust. It is big as a
city.
A massive ball of very hot and very bright
gas
A rocky ball orbiting a planet or a dwarf
planet
A huge star, many times bigger and brighter
than the Sun
Revision : numbers
100
one hundred
1 000 000 000
One billion
1 000
one thousand
1 000 000 000 000
One trillion
10 000
ten thousand
100 000
one hundred thousand
1 000 000
One million
5 123 789 456 258 = 5 trillion one hundred and
twenty three billion seven hundred and eightynine million four hundred and fifty-six thousand
two hundred and fifty-eight
Write the following numbers in letters :
14 258 :
..........................................................................................................................
9 687 215 : ..........................................................................................................................