Chapter 15

2. a huge explosion where a massive star collapses and throws its outer layers into space
5. a named star pattern that is not one of the 88 recognized constellations
7. the sum of all space, matter, and energy that has ever existed and will ever exist
9. scientist who proposed that the universe is expanding
10. the distance light travels in a year
12. the distance from the earth to the sun
14. a large reddish star late in its life cycle
16. celestial objects that can be viewed year round are _______
17. the North Star

1. a group of stars that form a recognizable pattern traditionally named after its apparent form
2. a large celestial body made of hydrogen and helium that emits light
3. the alpha star is the ____ star is a constellation
4. a collection of stars dust and gas bound together by gravity
6. a tightly sound spiral galaxy
8. a small hot, dim star that is the leftover center of an old star
11. the outermost layer of the suns atmosphere
13. an object so massive and dense that not even light can escape it
15. he innermost layer of the sun where fusion takes place