Sun/Solar system

2. The central region of the sun, where nuclear fusion takes place.
4. the process by which energy is produced in stars.
7. A unit of distance equal to the average distance between Earth and the sun, about 150 million kilometers.
9. A dark area of gas on the sun’s surface that is cooler than the surrounding gases.
10. Dark, flat areas on the moon’s surface formed from huge ancient lava flows.
11. The inner layer of the sun’s atmosphere that gives off its visible light; the sun’s surface.
14. One of the small asteroid-like bodies that formed the building blocks of the planets.
17. The effect of trapping heat near a planet’s surface by certain gases in the planet’s atmosphere.
18. An object that orbits the sun and is spherical, but has not cleared the area of its orbit.
19. The name often given to the four inner planets: Mercury, Venus, Earth, and Mars
20. An object that orbits a star, is large enough to have become rounded by its own gravity, and has cleared the area of its orbit.

1. Outer layer of the sun’s atmosphere, which looks like a white halo
3. This zone is the outermost layer of the sun’s interior.
5. The middle layer of the sun’s atmosphere.
6. A large round pit caused by the impact of a meteoroid
8. A zone of very tightly packed gas in the sun’s interior where energy is transferred mainly in the form of electromagnetic radiation.
10. A chunk of rock or dust in space, generally smaller than an asteroid.
12. A stream of electrically charged particles that emanate from the sun’s corona.
13. The system consisting of the sun and the planets and other objects that revolve around it.
15. An eruption of gas from the sun’s surface that occurs when the loops in sunspot regions suddenly connect.
16. A huge, reddish loop of gas that protrudes from the sun’s surface, linking parts of sunspot regions.