The solar system

4. one of the highly dense planets nearest to the sun; Mercury, Venus, Earth, and Mars
6. a large, reddish star late in it's life cycle
8. an object so massive and dense that not even light can escape its gravity
10. a small, rocky object that orbits the sun, usually in a band between the orbit of Jupiter and Mars
11. contains the sun and all of the planets and other bodies that travel around in it
13. a small, hot, dim star that us the leftover center of an old star
15. a group of stars bound by gravity
16. a large celestial body that is composed of gas and emits light; the sun is a typical star
17. the change in the illuminated area of one celestial body as seen from another celestial body;phases of the moon are caused by the position of Earth,the sun,and the moon
19. Any of the nine primary bodies that orbit the sun; a similar body that orbits another star
20. a small body of ice, rock, and cosmic dust loosely packed together that follows an elliptical orbit and that gives off gas and dust in the form of a tail as it passes close to the sun
21. a collection of stars, dust and gas bound together by gravity

1. the distance that light travels in one year; about 9.5 trillion kilometers
2. a accumulation of matter
3. a natural or artificial body that revolves around a planet
5. a large cloud of dust and gas in interstellar space; a region in space where stars are born or where stars explode at the end of their lives
7. an event in which the shadow of one celestial body falls on another
9. a planet that has a deep, massive atmosphere, such as Jupiter, Saturn, Uranus, or Neptune
12. a model for the formation of the solar system in which the sun and planets condense from a cloud (or nebula) of gas and dust
14. the portion of Earth that is water
18. a gigantic explosion in which a massive star collapses and throws its outer layers into space; plural supernovae