Across
- 4. the brightness that a star would have at a distance of 32.6 light-years from Earth
- 5. the theory that all matter and energy in the universe was compressed into an extremely small volume that 3 to 15 billion years ago exploded and began expanding in all directions
- 10. a collection of stars, dust, and gas bound together by gravity
- 11. quasi-stellar radio source; a very luminous object that produces energy at a high rate
- 12. a rapidly spinning neutron star that emits pulses of radio and optical energy
- 15. one of 88 regions into which the skay has been divided in order to describe the locations of celestial objects; a group of stars organized in a recognizable pattern
- 16. the brightness of a star as seen from the Earth
- 18. a star that suddenly becomes brighter
- 20. an object so massive and dense that even light cannot escape its gravity
Down
- 1. a very large and bright star whose hot core has used most of its hydrogen
- 2. a large cloud of gas and dust in interstellar space; a region in space where stars are born
- 3. radiation uniformly detected from every direction in space; considered a remnant of the big bang
- 6. a star that has collapsed under gravity to the point that the electrons and protons have smashed together to form neutrons
- 7. a large celestial body that is composed of gas and that emits light
- 8. the location on the H-R diagram where most stars lie; it has a diagonal pattern from the lower right to the upper left.
- 9. the study of the origin, properties, processes, and evolution of the universe
- 13. the distance that light travels in one year
- 14. a very large and bright star whose hot core has used most of its hydrogen
- 17. an observed change in the frequency of a wave when the source or observer is moving
- 19. an apparent shift in the position of an object when viewed from different locations