Astronomy is the study of everything in the universe beyond Earth's atmosphere. That includes objects we can see with our naked eyes, like the Sun , the Moon , the planets, and the stars . It also includes objects we can only see with telescopes or other instruments, like faraway galaxies and tiny particles.

Any characteristic that can be measured, such as an object's density, color, mass, volume, length, malleability, melting point, hardness, odor, temperature, and more, are considered properties of matter.