AST 2003 Lecture Notes - Lecture 2: Ecliptic, Magellanic Clouds, Black Hole Sun
Document Summary
Sun: spins around the black hole 230-250 km/s, half a million miles per hour, one galactic revolution takes about 250 million years, one galactic year ago our planet was jurassic (dinosaurs) Nearby star: earth is on the cygnus arm that is under the sagittarius arm and above the orion arm, m42=orion nebula, m1=pulsar is on the perseus arm, andromeda. We are in collision course with the andromeda galaxy: groups. 3 spiral galaxies and 30-40 irregular galaxies group together because the gravity attracts. The local group of coma berenice galaxy has about 1000 members. The virgo galaxy has about 2000 members. Some other galaxies are centaurus cluster, hercules, perseus. A cluster of different galaxies is considered a super cluster (putting all of the galaxies mentioned above and grouping them together. ) The universe: the universe is expanding and accelerating. Other superclusters are constantly moving away from each other and becoming faster: gravity is not strong enough and isn"t holding together very well.
