Across
- 3. A round pit on a moon's surface
- 6. The spinning motion of a planet about its axis
- 7. A contracting cloud of gas and dust; the earliest stage in a star's life
- 9. The presumed final stage of a white dwarf
- 12. An object that revolves around another object in space
- 16. A star that has collapsed under its own gravity
- 18. A meteoroid that has hit the Earth's surface.
- 20. The movement of an object around another object
- 21. All of space and everything around it
Down
- 1. The path of an object as it revolves around another object in space
- 2. The two days of the year on which neither hemisphere is tilted toward or away from the sun.
- 4. A small rocky body orbiting the sun
- 5. A natural object that orbits a planet
- 8. A large body in space that orbits a star and does not produce light of its own
- 10. A celestial body of hot gases that radiates energy derived from thermonuclear reactions in the interior
- 11. an object in space whose gravity is so strong not even light can escape
- 13. A streak of light in the sky produced by the burning of a meteoroid in Earth's atmosphere
- 14. A pattern of stars in the sky
- 15. A system of millions or billions of stars, together with gas and dust, held together by gravitational attraction.
- 17. A large cloud of gas and dust in space that is the first stage of star formation.
- 19. A piece of interplanetary material that falls toward Earth and enters its atmosphere