Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Question regarding gravitational waves

  1. Dec 19, 2011 #1
    1. The problem statement, all variables and given/known data
    A star 10 light-years away explodes and produces gravitational waves. How long will it take these waves to reach the earth?

    2. Relevant equations
    The problem is, I don't know what equations to use or if it's just a matter of simple math.

    3. The attempt at a solution
    My answer is that it takes 10 years to reach the Earth, but something tells me that this is wrong. Can anyone help me solve this problem or tell me if my answer is correct? :frown:
  2. jcsd
  3. Dec 19, 2011 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    As far as I know, gravitational waves propagate with speed c.
  4. Dec 19, 2011 #3
    The answer will depend on whether you are required to take into account the metric expansion of space; if not than your answer is correct as the waves propagate at the speed of light.
  5. Dec 19, 2011 #4
    Do all gravitational waves propagate at the same speed? Is it only the magnitude which varies, according to the body of matter that produced the waves?
  6. Dec 19, 2011 #5


    User Avatar
    Science Advisor
    Homework Helper

    For small amplitude gravitational waves they propagate at speed c. An exploding star counts as a small amplitude wave. Just use c.
  7. Dec 20, 2011 #6
    Thanks a bunch! :biggrin:
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook