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Light year question?

  1. Mar 11, 2009 #1
    1. The problem statement, all variables and given/known data
    If a star explodes 30 light years from the earth when will we be able to see it?

    2. Relevant equations

    one light year = 9.47 x 1012km
    speed of light = 3.00 x 108m/s

    3. The attempt at a solution
    the answer in my workbook says 30a but idk what the value of a is
  2. jcsd
  3. Mar 11, 2009 #2
    The definition of light year tells us that light will take 30 years to travel that distance, so the answer is indeed 30 years.
  4. Mar 11, 2009 #3


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    Staff Emeritus
    Science Advisor

    a could be an abbreviation for annum (year) or anni (years).
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