Results 1 to 4 of 4

Thread: Dark matter and moving away galaxies

  1. #1
    Join Date
    Nov 2012
    Posts
    2

    Dark matter and moving away galaxies

    If the galaxies are linked or connected to each other by dark matter or gravity, then why are they moving away from each other ?

    http://arstechnica.com/science/2012/...laxy-clusters/

    ( I understand Andromeda and Milkyway are moving towards each other but most of the rest of the galaxies are moving away !)

  2. #2
    Join Date
    Jul 2005
    Location
    Massachusetts, USA
    Posts
    21,855
    I moved this to Q&A.
    Forming opinions as we speak

  3. #3
    Join Date
    Aug 2003
    Location
    The Wild West
    Posts
    9,438
    Quote Originally Posted by mgsirius View Post
    If the galaxies are linked or connected to each other by dark matter or gravity, then why are they moving away from each other ?
    The clusters in that article are not moving apart. But when we see galaxies billions of lightyears away (in any direction), they appear to be moving away. We say the Universe is expanding. Exactly what that means depends on the details of the model you're using to explain it.

    Big clusters of galaxies make up a huge amount of mass. All that mass, and the accompanying dark matter, makes for a lot of "local" gravity, and that overwhelms the expansion in that region. The expansion is extremely small judging locally. But it adds up over the huge expanses of space between distant clusters.
    Everyone is entitled to his own opinion, but not his own facts.

  4. #4
    Join Date
    Nov 2012
    Posts
    2
    Thanks.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •