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Unformatted text preview: Speed of Light-light can travel very fast: 3x10^8 meters per second (m/s)-That’s 186,000 miles per second!-Even at this speed, light takes years to travel between the stars.-The distance light can travel in 1 year is called Light Year . (l.y.)-One light year = 1 x 10^16 meters Light Years-Light-Year is a unit of distance-a light-second is the distance light travels in one second. =186k miles-the sun is 8 light-minutes away-the nearest star to the sun is 4 light years away-the nearest galaxy is 2 million light-years away. Looking Back in Time-although light travels fast, it does not move instantaneously.-for example star Rigel (in orion) is 800 light years away.-it takes light from rigel 800 years to reach us.-so we see Rigel as it was 800 years ago!-we see the closest galaxy (Andromeda) as it was 2 million years ago. Betelgeuse: 640 light years...
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- Spring '11
- Speed of light, Astronomical unit, Rigel