Across
- 4. the brightness that a start would have at a distance of 32.6 light-years from Earth
- 5. the theory that all matter & energy in the universe was compressed into an extremely small volume that 13-15 billion years ago exploded & began expanding in all directions
- 10. a collection of stars, dust, & 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 & optical energy
- 15. 1 of 88 regions into which the sky has been divided in order to describe the location of celestial objects; a group of stars organized in a recognizable pattern
- 16. the brightness of a star as seen from Earth
- 18. a star that suddenly becomes brighter
- 20. an object so massive & dense that even light cannot escape its gravity
Down
- 1. a small, hot, dim star that's the leftover center of an old star
- 2. a large cloud of gas & 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 & protons have smashed together to form neutrons
- 7. a large celestial body that's composed of gas & 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, & evolution of the universe
- 13. the distance that light travels in 1 year
- 14. a very large & 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