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

Gravitational center of the Local SuperCluster

  1. Jun 19, 2013 #1
    I spent days trying to find this information on the internet, but i think i will never find it, so i came here looking someone who knows it.

    The Mystery is : Where is the Gravitational center of the Local SuperCluster (Also known as Virgo SuperCluster) ?

    Some Usefull information that i found in my research
    1 - The Gravitational center of the Local Group lies between the two largest galaxies of the group Milky Way And Andromeda (this group contains 54 galaxies)
    2 - The Local SuperCluster contains around 100 galaxy groups including the Local Group, and the important (for the context) Virgo Cluster/Group
    3 - the Virgo Cluster contains approximately 1300 and is the most massive group of galaxies in the local supercluster. According to wikipedia the virgo cluster is the center of the Local Supercluster, and the galaxy m87 is the center of the virgo cluster, BUT no reference is cited.

    My supposition is that the entire Local Supercluster , including the milky way , Revolves around the massive galaxy m87.

    Can this be true?

  2. jcsd
  3. Jun 19, 2013 #2
  4. Jun 19, 2013 #3


    User Avatar
    Science Advisor
    Gold Member

    That would be the CoM of the Local Group, not the Local Super-cluster.

    We really don't know whether the Local Group is gravitationally bound to the Virgo cluster and the associated super-cluster, however AFAIK the LG is travelling more or less normal to the direction of M87 which may be a signal that it is orbiting around it.

    P.S. Is it only me or would others also not trust a site called "astrologysoftware"??

  5. Jun 19, 2013 #4
    Yeah I'm not sure on our movement towards " the great attractor" there is some debate on that. I realize the answer I provided was the local group and bot the virgo supercluster. M81 seems likely but I was searching for a technical paper covering that. Still having trouble finding a decent non model based article.
    I didn't want to post the MOND paper for several reasons for one it utilizes a 2 center of mass calculation milky way and Andromeda. However as its comparing MOND it didn't cover dark halos influence of CoM until the conclusion. Still digging for a decent technical article
  6. Jun 19, 2013 #5


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    The galaxy M87, in my opinion, must have a massive massive massive black hole at its center, about which the milky way and local group and virgo supercluster and M87 revolve. As far as i know, it is unknown if the rotation stops there, that is, whether the presumed Mother black hole at the center of M87 is itself in rotation about some other cluster of cluster of galaxies. The buck might stop there, I don't know. Gee Whiz, does anyone?
  7. Jun 19, 2013 #6
    Yes, there are people who know. Pretty much all you wrote except that M87 must have a massive BH is highly missleading.

    Some points:
    * Galaxies (and stars in galaxies) don't really 'revolve' around anything in the usual sense of the word.
    * Even though the black hole in M87 is very large (~6 billion M_sol) its just 0.1% of the total mass of the M87 galaxy.
    * Even the 6 trillion M_sol of M87 is not enough to be more than the largest player around. Distances and velocities between galaxies are just too high.
  8. Jun 19, 2013 #7


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Who are these people?
    so I looked it up. It was the most massive black hole ever discovered until recently when when was discovered 3 times more massive. At the No. 2 spot, it is still refrerred to as a supemassive black hole, making the BH at the Milky Way center look like a grape nut.
    I don't understand what you mean. Our own star, the sun , has already revolved around the black hole at the center of the Milky way galaxy about 20 times since its birth.
    and holding the number 2 spot for BH's in terms of its mass.
    My question still stands, does the BH at the center of M87 revolve about some other BH somewhere?
  9. Jun 19, 2013 #8
    PhanthomJay regarding your question, i think it should be rewritten to "Does our local superCluster revolve around some Gravitational center outside the local supercluster and share this orbit with one or more other superclusters ?" Because where the M87 BH goes it carries with him all the stars of the galaxy m87, and along with it the virgo cluster and 'not less important' and the groups that orbit the virgo cluster, including the LOCAL cluster.

    I looked for the answer on the internet but i did not found it. You may find the answer thru this questions :

    1 - Which SuperClusters are closer to the Local SuperCluster? do these have a gravitational influence on the local supercluster?
    2- Which SuperClusters are the largest (in mass) ? do these have a gravitational influence on the local supercluster?

    an hour ago, i found some information on the subject, and looks like that " Shapley Supercluster " and "Centaurus_Supercluster" exert some influence on our group.

    Importante fact : Within the proximity of this Centaurus_Supercluster lies the Great Attractor (!!!!), dominated by the Norma Cluster (Abell 3627). This massive cluster of galaxies exerts a large gravitational force, causing all matter within 50 Mpc to experience a bulk flow of 600 km/s toward the Norma Cluster (Reference : Harvard http://adsabs.harvard.edu/abs/1991MNRAS.249...46P)
  10. Jun 19, 2013 #9
    First off the mass of the BH is puny compared to the overall mass of the galaxy. Baryonic matter is a small 4% of the total mass. The BH represents an even smaller portion of that.
    DM halos contain far more mass. This makes calculations far more difficult as estimates of a galaxies dark halo is the value most needed. Also the orbit of our sun around our galactic center is nothing compared to galaxy movement towards a large scale cluster. Far greater distances are involved as well as expansion.

    While I was looking into this one article mentioned that outside of 7Mpc from m87 expansion is sufficient to overpower the gravity from M87. However I haven't been able to find a reliable paper stating that. The great attractor is also under debate. Needless to say its a good question and I am also curious as to the answer so will keep digging
  11. Jun 19, 2013 #10
    One paper suggested the Shapley supercluster that I came across as well
  12. Jun 19, 2013 #11

    this paper states the local void as the primary influence of our galaxies peculiar velocity. It mentions the Virgo cluster as a smaller influence.

    Edit: however this older article contradicts the first lol. Needless to say the answer is daunting lol
    Last edited: Jun 20, 2013
  13. Jun 20, 2013 #12
    Another article that may provide clues the most common answer is that were moving toward the virgo cluster but we are also influenced by the great attractor as well as the Shapley supercluster. Which represents the center of mass for our LG that accounts for the LG peculiar velocity I haven't been able to determine.

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook