The Universe

1. the stable period were the star spend 90% of its life
3. The collection of planets and their moons in orbit around the sun, located on the Orion Arm of the Milky Way
4. a collection of stars and gas held together by gravity
6. has a spiral shape with arms
8. A key factor in gravity; the force of gravity decreases as the distance between objects increases
10. A scatterplot chart used to classify stars by graphing their luminosity against their temperature
13. A unit of measurement representing the distance a star's light travels in one year
15. an explosions of a high mass star after they explode
18. a unstable stage were the star pulls gas together before fusion begins
19. shaped like a oval or football
20. One of the two primary factors (along with distance) that determines the gravitational attraction between two objects

2. A star characteristic determined by its color; blue stars are the hottest, while red stars are the coolest
5. The shed outer layers of a low-mass star as it transitions into a white dwarf
7. galaxies with no definite shape
9. the most massive stars after they explode
11. after main sequence where the star starts to lose fuel
12. where atoms smash together to release energy
14. The total amount of energy a star gives off from its surface
16. after mains sequence only high mass stars got through this
17. a hot, dim star that the a low mass star goes through after its outer layers are gone