Across
- 4. The moon shape where less than half is illuminated, looking like a sliver or a C
- 5. A massive system of billions of stars, gas, and dust bound together by gravity
- 6. All of existing matter, space, energy, and time considered as a whole
- 8. A small, rocky body orbiting the sun, mostly found in a belt between Mars and Jupiter
- 9. The phase where exactly the left half of the moon appears illuminated
- 12. A large celestial body orbiting a star that has cleared its orbit of other debris
- 13. The moon shape where more than half, but not all, is illuminated
- 16. The movement of one object around another, such as Earth completing one orbit around the sun
- 18. When the moon's illuminated area is shrinking or getting smaller
- 19. The collection of planets, moons, and smaller bodies that orbit around a sun
- 20. A natural satellite that orbits around a planet
Down
- 1. The scientific study of space, stars, planets, and the physical universe
- 2. When the moon's illuminated area is growing or getting larger
- 3. A relatively small, low-mass star, much like our own sun
- 4. A cosmic snowball of frozen gases, rock, and dust that grows a glowing tail as it approaches the sun
- 7. The phase where exactly the right half of the moon appears illuminated
- 10. The spinning motion of a planet or celestial object around its own invisible axis
- 11. The phase when the entire face of the moon is visible and brightly lit
- 14. One half of a planet or spherical celestial body
- 15. A massive, luminous sphere of hot gas and plasma held together by its own gravity
- 17. The phase when the moon is completely dark and not visible from Earth