Our Home In The Galaxy
Our galaxy has many solar systems. A solar system is a star with planets orbiting. Our sun is a star in the Milky Way Galaxy. We live in a solar system with nine planets and billions of asteroids and comets.
Our Solar System was formed by an exploding star. The Solar System is 7.6 trillion kilomtres in diameter or 1.6 light years and is 4.6 billion years old. The Solar System has 5 billion years left to live.
The nine planets in our Solar System were formed by rapidley moving peices of material that collided and formed together. The left over material began to orbit the Sun and became asteroids.
The planets in our Solar System form two groups, the inner planets and the outer planets. The inner planets are Mercury, Venus, Earth and Mars. The outer planets are Jupiter, Saturn, Uranus, Neptune and Pluto.
The inner planets are much smaller than the outer planets and are made of rock and metal. The outer planets are larger, with the exception of Pluto, which is the smallest planet in the Solar System. The first four outer planets are giant balls of gas with small solid cores. Pluto, however, is made up of rock, metal and snow.