Astronomers read the light
the sun and a large cluster of stars
Almost everything we know about the universe comes from studying the many kinds of light that reach Earth from space.

All human beings have their own unique fingerprints. Each object in the universe, such as stars and planets, also has its own fingerprint - written in light.

Light helps astronomers answer cosmic questions like: How old is the universe? What are stars made of? How far away is the next galaxy?