AST 10G Lecture Notes - Lecture 1: Cosmic Calendar, Milky Way, Virgo Supercluster
Document Summary
Solar system-earth, sun, planets and their moons, asteroids, icy comets (include countless sm obj) Milky way galaxy (~3x10^19km, 3 mill ly) huge disk shaped collection of stars; containing over 100billion. Galaxy-great island of stars, held together by gravity and orbiting a common center. Our s. s. located over from galactic center to edge of galactic disk. Galaxy & g. clusters; voids btw them. Super cluster-region where g. &g. c. tightly packed (clusters of g. c. ) Our local group located outskirts of local supercluster (laniakea) Universe-sum total of all matter and energy, encompassing the supercluster, voids, etc. w/n them. 150 mill km=93 mill mi (dist. w/in solar system au) Speed of light= 300,000km/sec light travels 10trillion km/year ly-distance light travel 1year=10trill km=6 trill mi. (dist. stars & galaxies) unit of dist. Sirius (brightest star) 8 ly (8 years ago we see it) Orion nebula-giant cloud, planets and stars are forming (~1350ly) The andromeda galaxy (~2. 5mill. ly away) 100,000 ly diameter.
