Astronomy Basics
Astronomy is the science of space: the study of planets, moons, stars, galaxies and everything else beyond Earth's atmosphere.
Astronomy is not astrology
Astronomy and astrology are different things. Astronomy is a science that observes, measures and explains the universe. Astrology is a belief system that claims the positions of stars and planets affect people's lives, and it is not science. This site is about astronomy only.
How astronomers learn about space
Astronomers study light and other radiation from distant objects, using telescopes on the ground and in space, along with spacecraft that visit nearby worlds. From this they work out what objects are made of, how they move and how they change over time.
A tour of topics
The Solar SystemThe Sun, the eight planets, their moons and the smaller bodies that orbit the Sun.
StarsHuge balls of hot gas that shine by nuclear fusion. The Sun is our nearest star.
GalaxiesVast collections of stars, gas and dust. Our home is the Milky Way.
Start stargazingSimple, free ways to begin looking at the night sky yourself.