Across

5. A gassy planet with a spectacular ring system.
6. Appearance of a moon or planet - full, new or crescent for example.
7. This orbits a star and reflects the star's light.
8. Planet nearest the Sun.
12. A blue planet, outermost of the gassy planets in our solar system.
17. A small lump of rock or metal that moves around the Sun, mainly between Mars and Jupiter.
19. Spin on its axis.
20. This means that something gives out light.

Down

1. Huge gassy planet with a giant red spot.
2. A huge ball of gas that emits light. Our Sun is one.
3. This orbits a planet, our moon is one.
4. The path of a planet around the Sun, or a satellite around a planet.
9. Third largest planet in our solar system, seventh furthest from the Sun.
10. Hot planet with acidic clouds, second closest to the Sun.
11. When the moon casts a shadow on the Earth.
13. Planet usually furthest from the Sun.
14. A group of millions of stars.
15. Our home, the third planet from the Sun.
16. Red planet with canyons, volcanoes and polar ice caps.
18. How much a line departs from the vertical.