American astronomer Edwin Hubble used his telescope to study the light from neighboring galaxies and discover evidence for the expansion of the universe. In studying spectra from remote galaxies, he was able to observe the shift in light waves. These observations led him to Hubble's law, which states that speed at which other galaxies move away from our galaxy is proportional to their distance from the Earth.
What contributions did Kepler make to astronomy?
Answered by Craig C. Freudenrich and Discovery Channel
How did Cepheids become measuring posts?
Answered by Discovery Channel
How do exoplanets get their names?
Answered by Dr. Gerard van Belle