An astronomer is a scientist who studies stars, planets, galaxies, and everything else in space beyond Earth's atmosphere. While anyone can look up at the night sky and wonder about the twinkling lights, astronomers use powerful telescopes, mathematics, and physics to understand what those lights actually are, how far away they are, what they're made of, and how they move through space.

Ancient astronomers tracked the movements of planets and stars without telescopes, using only their eyes and careful record-keeping. They discovered patterns in the sky that helped people navigate ships across oceans and know when to plant crops. Modern astronomers have sent telescopes into space and built enormous observatories on mountaintops. They've discovered that our sun is just one star among hundreds of billions in our galaxy, and that our galaxy is just one among trillions in the universe.

Some astronomers spend their nights collecting data from telescopes, while others work during the day analyzing that data on computers or developing theories about black holes, distant planets, or the birth of stars. Astronomers today study far more than just stars: they investigate asteroids, comets, dark matter, and even search for planets around other stars that might support life.