The Universe

3. Massive stars can end up as a black hole or this.
4. an enormous explosion that destroys a star.
6. the spiral galaxy of which the Sun and the solar system are a part.
9. The main factor determining whether a star will become a white dwarf or black hole.
10. a star that fuses hydrogen into helium in its core.
12. a graph that plots luminosity v. temperature of stars.
15. a galaxy with no identifiable shape or structure.
16. a cloud of gas and dust.
17. This is associated with the temperature of a star

1. The measure of the amount of brightness of a star.
2. the distance light travels in one year.
4. a large ball of gas held together by gravity with a core so hot that nuclear fusion occurs.
5. a galaxy that has a generally elliptical shape and that has no apparent internal structure or spiral arms
7. forms as the core of a giant star no longer supports fusion and the star’s outer layers escape into space, leaving a hot and dense core.
8. These stars are very bright and have the lowest temperatures
11. a star with a much larger radius and luminosity than a main sequence star of the same surface temperature.
13. a galaxy exhibiting a central nucleus from which extend curved arms of higher luminosity.
14. an area in space that is so dense that nothing, including light, can escape its gravitational pull.