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

Can we expect stars to become visible only in infrared after a while?

  1. Mar 11, 2013 #1
    I wonder if some old stars will become invisible to our eyes after a while because of the redshift?
    Since they get further away from earth, maybe we won't receive their radiation in visible light any more?
    I'm talking about stars that are not obscured by any other objects or dust, which you don't have to detect them in infrared (IR).
    If the answer is yes, then how long will it take for a star to be obscured to us because of the redshift? Say a star that is 5 billion years from us and getting further away each day.

  2. jcsd
  3. Mar 11, 2013 #2


    User Avatar
    Gold Member

    Stars are contained in galaxies. All of the galaxies in the universe, except those in the local cluster of galaxies, are moving away from us and eventually will be outside of the Earth's observable universe and yes they will redshift as they go. This will take a LONG time. Those currently at the edge of the observable universe are already significantly redshifted.
  4. Mar 11, 2013 #3
    How long?
    I mean, in the order of magnitude.
    tens of billions of years or maybe millions of billions of years?

    When can we expect to see the fist galaxy that completely redshifted in infrared?
  5. Mar 11, 2013 #4
    Considering the observable universe is 47 billion years in radius and we can see objects at extreme redshift I would say that describes your order of magnitude. in 10's of billions.

    The cosmic microwave background has a redshift of z=1089, corresponding to an age of approximately 379,000 years after the Big Bang and a comoving distance of more than 46 billion light years


    in a section on this page it will describe various objects as the earliest detected such as the highest redhift to a galaxy
    Last edited: Mar 11, 2013
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook