What do astronomers observe to find clues as to how our solar systems are formed?

a. Patterns of motion among large bodies- Sun, planets, large moons rotate in an organized way (co-planar)—nearly circular orbits in the same direction (coplanar and prograde)

b. Two major types of planets- terrestrial vs. jovian planets

c. Asteroids and comets- locations, orbits, and compositions follow distinct patterns—Asteroids are b/t Mars and Jupiter in the asteroid belt. Also located in the Kuiper belt and Oort Cloud

d. Exceptions to the rules- Earth is inner planet with large moon, Uranus is only side tilted axis, etc.

Hope this helps

mass and volume are the answers you are looking for