Across
- 2. person who discovered other galaxies within universe
- 5. The person who discovered the planet Uranus
- 7. the year astronomers received first visual proof of black holes
- 8. name of the united states first satellite
- 9. who launched the first rocket
Down
- 1. thought to be a planet between mars and jupitor; proved to be the astroid belt
- 2. The name of a comet after its reappearance
- 3. person that helped mankind scale the size of the universe
- 4. measures energy given out by different colors
- 6. measures brightness of stars