The Planets: Ice Worlds

5. The object with mountains ice blades and craters on its surface is ____.
6. Triton is covered in frozen ______.
7. Voyager used the ______________ of other planets to give itself a speed boost.
10. In terms of temperature Neptune is _____ than Uranus.
12. The ______ (2 words) is made up of frozen lumps of water ammonia and methane.
13. Pluto is now considered a _____ (2 words).
14. Pluto’s interior generates heat through radioactive ____.
15. The most remote primitive body we have visited is _____ (2 words).
17. Triton is unusual because its spin is ______ to Neptune’s.
19. The gas that makes Uranus look blue is ______.
20. The most recent spacecraft to visit Pluto is ____ (2 words).
22. Winds on Neptune are the _____ in the solar system.
23. Pluto was demoted because it doesn’t _____ its orbit.

1. ____ is the largest of Neptune’s moons.
2. As Triton warms pressure builds up below the surface and forms _____.
3. Uranus doesn’t have big storms because there is not enough _____ to drive them.
4. The heat on Neptune is created by a buildup of ______.
8. New Horizons’ last picture was of Pluto’s ________.
9. Uranus orbits like it has been ______ over on its side.
11. The big storm on Neptune is called the _____ (3 words).
16. The _____ probe was the first to visit the outer planets.
18. Chemically Uranus and Neptune are _______.
21. Scientists think there might be a layer of liquid _____ below Pluto’s surface.