ASTR 1P01 Lecture Notes - Lecture 1: Milky Way, Virgo Supercluster, Globular Cluster
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ASTR 1P01 Full Course Notes
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Spins/rotates around north-south axis and the direction of the spin is counterclockwise (prograde) if observed from above the north pole which is from west to east. The sun rises in east and sets in west because of it rotating from west to east. The distance from it to the moon is 384,500 km. Time = distance/speed of light = time it would take for light to travel from point a to point b. *the greater the distance, longer the lookback time* Usually distances in solar system are expressed in terms of earth-sun distance. *astronomical unit (au)* = avg earth to sun distance = 150 million km. It takes 8. 3 minutes for light emitted from sun to hit earth (use same formula as before and convert seconds to minutes) 150 million km/300,000 km/s = 500 sec = 8 minutes 20 seconds. One light minute ( min/au) = distance light travels in a minute.
