(a) The distance to Polaris, the North Star, is
Chapter 21, Problem 21.79(choose chapter or problem)
(a) The distance to Polaris, the North Star, is approximately 6.44 _ 1018 m. If Polaris were to burn out today, how many years would it take to see it disappear? (b) How long does it take sunlight to reach Earth? (c) How long does it take a microwave signal to travel from Earth to the Moon and back? (The distance from Earth to the Moon is 3.84 _ 105 km.)
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