Galaxies are groups of stars. The Universe is a sea of galaxies, not stars. Explore the Milky Way Galaxy, star clusters, interstellar medium, and black holes.
What does the “M” in M31 or M11 stand for? Messier [Me-Si-Eh]
Charles Messier (1758-1772), a French astronomer, identified about 110 diffuse fuzzy objects that he named “Messier objects.” Messier then cataloged these objects in his Messier Catalog. He also discovered 13 comets; finding comets was a way to make a name for astronomers of the 18th century).
M42: Orion Nebula
- local region in the Milky Way (~1,300 light years away) with new stars
- appears mostly red due to hydrogen gas abundance
- ~12 million light years away
- clouds of glowing hydrogen blown out, released by recent star formation
M31: Andromeda Galaxy
- hundreds of nebulae (discovered 20th century)
- with George E. Hale’s idea and Hooker’s money –> the Hooker Telescope (100-inch in diameter, 11 years to build, $100 million)
Today, the Sloan Digital Sky Map holds 15 Terabytes of data on the Universe.