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

Universe expansion faster than light?

  1. Jan 20, 2013 #1
    The speed of light is a constant. Yet the Universe's expansion seems to be getting faster and faster.

    So my question is, when the speed of the expansion of the Universe reaches C the speed of light, what happens. Does it remain at that speed? Does it exceed it? Or does it slow down?
  2. jcsd
  3. Jan 20, 2013 #2
    As I understand it, the speed of light is the upper limit of the speed of things moving in space and does not limit the speed at which space itself moves. Thus it is possible to conjecture that at some early stage of the universe, space did in fact expand at a speed greater than the speed of light.
  4. Jan 20, 2013 #3


    User Avatar
    Gold Member

    Google "metric expansion" to explain it all
  5. Jan 20, 2013 #4
    From what I understand, the fabric of the universe is expanding at a rate greater than the speed of light already. We can see the light from stars 46+ billion light years away and the big bang happened less than 14 billion years ago. You would think that the light from the stars 46+ billion light years away would take 46 billion years to reach us therefore disagreeing with how long ago the big bang happened, but the reason we can see the light from those stars is because they used to be much closer.

    It's important to note that expansion of the universe and the motion of the objects within the universe are entirely separate concepts.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook