Astronomy

2. the process or result of joining two or more things together to form a single entity
5. Energy from the sun that is converted in to thermal energy
8. The center of celestial body that orbit around one another
9. System A collection of planets, moons, asteroids, comets, and other celestial bodies that orbit around a star, the Sun.
10. The force of attraction between to objects due to their mass
11. The belief that the Sun is the center of the universe.

1. The spinning of celestial body, such as planet around another celestial body such as a star
3. The entirety of space, time, matter, and energy, including all planets, stars, galaxies, and other celestial bodies.
4. The belief that the Earth is the center of the universe.
6. A system of millions or billions of stars, along with gas and dust, held together by gravitational attraction.
7. A celestial body that orbits around a star, is spherical in shape, and has cleared its orbit of other debris.