Stars and Galaxies

1. Light cannot escape its intense gravitational pull.
5. Gravity pulls particles together and energy is converted to heat.
6. A galaxy with no particular shape, rich in gas and dust.
8. A star's true brightness.
10. Fusion occurs during this stage, 90% of all stars in an H-R diagram are in this stage.
12. Interstellar dust and gases such as hydrogen, helium and heavy elements.
15. A cloud of gas which forms when Helium fuses to Carbon.
17. A dead star.
18. A massive, relatively cool star and expands and contracts and make heavy elements up to Iron.

2. A galaxy with the shape of a sphere to a disk, most common type of galaxy.
3. A galaxy with flattened arms and a bar through the center.
4. A hot dense core that shines for billions of years.
7. When massive stars terminate in a brilliant explosion.
9. Brighter than a main sequence star, happens when about 20% of Hydrogen fuses into Helium.
11. A pinwheel galaxy with a nucleus of bright stars.
13. Affected by a star that's further away.
14. A star is born when this begins.
16. A super dense ball of neutrons with relatively low mass.