Across
- 2. The big bang theory explains the origin of the _____.
- 3. The distance between stars is typically measured in _____.
- 6. The life cycle of a star begins with a cloud of gas and dust called a ____.
- 8. More than half of all stars are members of a star ____.
- 10. the sun's energy is produced by _____.
- 12. Astronomers classify stars according to their color, size, and _____ brightness.
- 14. Low-mass and medium-mass stars eventually turn into __________.
- 15. An H-R diagram graphs a sample of stars according to surface _____ and absolute brightness.
Down
- 1. Dark matter can be detected by its gravitational effects on ____ matter.
- 4. All stars remain on the main _________ for about 90 percent of their lifetimes.
- 5. A large group of older stars would be found in which star cluster?
- 7. _____ are usually larger and have fewer stars than open star clusters.
- 9. Both high-mass and low-mass adult stars are classified as ______ stars.
- 11. When the absorption lines of a galaxy shift toward the red end of the spectrum, it means that the galaxy is moving away from ____.
- 13. Galaxies are classified into four groups based on their _____.