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

A Problem with (Almost) Universal Red Shift

  1. Jul 29, 2011 #1
    It is my understanding that, except for a couple of local galaxies, everything in the universe is moving away from us as well as from each other (relationships between inhabitants of local galactic groups excepted). If my information is acurate, how is it that a large collection of randomly placed objects could possibly act in that way? Wouldn't some of them have to be moving toward us?

    I ask because the only way that makes sense to me is if all super massive objects/groups in the universe are actually motionless and the spacetime between them is expanding. Any motion at all from them would, in some direction, be read as a blue shift and just by the strength of numbers, some of those blue shifts would be pointing in our direction.
     
  2. jcsd
  3. Jul 29, 2011 #2

    phinds

    User Avatar
    Gold Member
    2016 Award

    I believe (not really sure) that distant galaxies DO have a local motion that is random relative to their direction to earth, BUT this motion is utterly trivial relative to the "motion" we see due to expansion.
     
  4. Jul 29, 2011 #3

    Drakkith

    User Avatar

    Staff: Mentor

    Sure, there are variations where some have more motion towards us than others do, but as you get further and further away the average redshift steadily increases.
     
  5. Aug 3, 2011 #4

    Chronos

    User Avatar
    Science Advisor
    Gold Member

    No mystery here. This is the foundation for the expanding universe idea.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: A Problem with (Almost) Universal Red Shift
  1. Red shift (Replies: 4)

  2. Red Shift (Replies: 2)

Loading...