Across
- 1. one arcsecond of parallax (about 3.26 light years)
- 5. chance alignment where one astronomical object passes in front of another
- 9. the most abundant element in the universe
- 11. proved the Andromeda "nebula" was outside our Galaxy
- 13. change to the frequency of light due to Doppler Effect
- 14. unit of length, about the diameter of a hydrogen atom
- 15. the unknown effect driving the expansion of the Universe. _____ energy
Down
- 1. rapidly spinning neutron star
- 2. the second most abundant element in the universe
- 3. variable star whose pulsation period is related to its absolute luminosity
- 4. the nearest spiral galaxy to the Milky Way (M31)
- 6. name of the nearest star to Earth
- 7. object of known brightness, used to calibrate distances. standard _____.
- 8. stellar remnant, supported by electron degeneracy pressure. _____ dwarf
- 10. 7 classical stellar spectral types
- 12. unit of energy, in the CGS system