Astronomy

3. An object's spinning motion about its own axis
4. A system of billions of stars, together with gas and dust
6. Frozen leftovers from the formation of the Solar System
8. All existing matter and space as a whole
10. Complete or partial obscuring of a celestial body by another
13. The Earth is at the center of the universe and other planets go around it
15. Collection of 8 planets and their moons in orbit around the Sun
16. Device to demonstrate the Earth's rotation
17. Brightness of a celestial object
18. Meteoroid that burns up in the atmosphere (shooting star)
19. The center of interest or activity
20. The revolving of one object around another in an oval-shaped path

1. Small, rocky objects that orbit the sun
2. A group of stars that looks like a particular shape
5. The region in space between the orbits of Mars and Jupiter, containing the greatest population of asteroids in our solar system
7. The idea that the universe began as just a single point, then expanded and stretched to grow as large as it is right now
9. Distance above the sea level
11. The Sun is at the center and other planets go around it
12. Movement of an object in a circular or elliptical course around another or about an axis or center
14. Physical entity that exists in the observable universe