Solar System

2. The biggest planet in the solar system
5. A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing.
7. The coldest planet in the solar system
8. Small, rocky objects that orbit the Sun.
11. The theory that the Sun is at the center of the solar system
15. the planets past the asteroid belt

1. The theory that Earth is at the center of the solar system
3. The area of air and gas that envelopes Earth and other astronomical objects.
4. The closest planet to the Sun
6. A place in space where the pull of gravity is so strong that even light can't get out.
9. The planet we live on
10. Earth's only natural satellite.
12. The planets that come before the asteroid belt.
13. A person trained to travel in a spacecraft.
14. Objects that are round and orbit the sun.