| A | B |
|---|
| star | large celestial body composed of gas and that emits light |
| light-year | the disatnce that light travels in one year; about 9.5 trillion kilometers |
| red giant | a large, reddish star late in it's life cycle |
| white dwarf | a small, hot, dim star that is the leftover center of an old star |
| supernova | a gigantic explosion in which a massive star collapses and throws its outer layer into space |
| black hole | an object so massive and dense that not even light can escape its gravity |
| galaxy | a collection of stars, dust, and gas bound together by gravity |
| cluster | a group of stars or galaxies bound by gravity |
| interstellar matter | the gas and dust located between the stars in a galaxy |
| quasar | quasi-stellar radio sources; very luminous objects that produce energy at a high rate and that are thought to be the most distant objects in the universe |
