Across
- 1. the distance to an imaginary star
- 3. very small stellar parallaxes
- 5. least possible energy
- 6. used to classify stars into nine principal types
- 9. measuring the distances to nearby stars
- 10. elements that have its own unique set of allowed electron orbits
- 12. problem of ascertaining the actual positions and motions of stars
- 13. atom that radiates
- 14. the apparent change in a star’s position
- 15. each elements atoms have a nucleus with a unique number of positively charged protons
Down
- 2. the analysis of spectra
- 4. distance to the star
- 7. first-magnitude star exactly 100 times bigger than a sixth-magnitude star
- 8. an electron in a particular orbit
- 11. atom is unstable