january 23, 2008

january 23, 2008 - January 23, 2008 Circumpolar stars are...

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January 23, 2008 Circumpolar stars are always above the horizon (clicker question) Measuring distance with light o Based on the finite speed of light (300,000 km/s) o Based on the face that DISTANCE = SPEED X TIME How much time does it take light to travel one astronomical unit (1 AU) o 1 AU/ speed of light o Speed = distance/time Time = distance/ speed Time = 1 AU/ speed of light Over astronomical distances, even light takes a lot time to travel between the stars o This means that what we see in the distant universe is light that has traveled a long time just to get to us o Our image of the universe is a delayed image Looking back in time Further distance = further back in time Lookback time o The image of a galaxy spreads across 100,00 years of time o Try to think of what we see now as difference from what may exist now We see a bright supernova explode in the Andromeda galaxy ( the other big galaxy in the local group). The remnant from such explosions disperse in about
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This note was uploaded on 04/07/2008 for the course ASTR 1110 taught by Professor Hornstein during the Spring '08 term at Colorado.

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january 23, 2008 - January 23, 2008 Circumpolar stars are...

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