Earth

The Universe includes everything we know but no one knows its size, how it began or when it will end. Some astronomers say that the Universe was formed in the distant past when a single body of matter exploded to form galaxies which spread out through space.

A galaxy is a huge collection of Stars, gas and dust. Our own star, the sun, is one of the more than 100000 million stars that make up our galaxy, the milky Way.