Unit 8 Vocabulary

4. Cloud of dust and gas. Birth place of all stars.
6. The distance light travels in 1 year. Approximately 6 trillion miles.
9. Pinwheel-shaped, has arms that move out from the center, ex: The Milky Way.
10. The explosion of a high mass or super high mass star.
13. Oval, round, flattened ball. Has NO arms.
15. States the universe started at a single point; expanded and continues to expand forever.
16. The distance between the crest of one wave and the crest of the next wave.
20. The number of electromagnetic waves traveling past a fixed point in a specific unit of time (usually one second).
21. A large celestial body of hot gas, primarily hydrogen and helium, that undergoes nuclear fusion.
22. The remains of a super high mass star after a supernova. Super strong gravity. Light can't even escape.
23. Brightness of a star compared to the sun.

1. A small to average sized star that is beginning to die.
2. A diagonal area on an H-R diagram where stars spend 90% of their lifetime.
3. Gravity pulls Hydrogen atoms together and they join creating Helium. Light and heat are released as a result. Causes stars to form and shine.
5. Galaxy with no definite shape.
7. The brightness of a star as seen from Earth.
8. Cluster of stars, gas, and dust held together by gravity.
11. Dead star; no longer fusing but is still glowing because it is very hot.
12. Arrangement of electromagnetic waves according to their wavelengths and frequencies.
14. The actual brightness of a star.
15. Completely dead star; not glowing.
17. Closest star to earth, main sequence, average mass star.
18. Is the classification system of temperature used on many HR Diagrams.
19. The remains of a high mass star after a supernova. Very small star.