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

Dark energy

  1. Nov 10, 2009 #1
    what if there was no such thing as dark energy to begin with?

    it is found that everything is accelerating away from us because of the red shift of light

    but what if we were all actually contracting to a point?

    | 0 |
    | 0 | x
    | 0 |
    | 0 |

    so the vertical lines are just space while the 0 are us earth. x is the point we are contracting towards due to gravity

    so the space nearer to the point accelerates faster ,due to a greater force from the inverse square law of gravity, as opposed to us earth . thats why it appears that they are speeding up away from us , resulting in the red shift

    now with respect to the space behind us, it is also accelerating but not as much as earth, so it's relative acceleration is actually slower with respect to earth's acceleration towards the point x , thus the space behind us appears to be moving away from earth, resulting in the red shift too...

    so point x could mean a really super massive blackhole or sorts that is pulling everything towards it.

    does my idea makes sense or is it wrong?
  2. jcsd
  3. Nov 10, 2009 #2
    I would be very suprised that x would be a super massive blackhole, and please define(pulling everything)
  4. Nov 10, 2009 #3
    pulling everything is the gravitational forces that it exerts on all else.

    just like how the sun pulls everything (planets) towards it,
    the massive blackhole in the middle of the milky way pulling everything towards it
    the point X( super super massive object) pulling all else towards it
  5. Nov 11, 2009 #4
    What about the matter that is at a right angle to the line between your perspective and the black hole.
    You have covered the matter "in front" of and "behind" your perspective. But what about to your "left" and "right"?
    They would exhibit no red shift.
    And thus your theory would not account for the fact that all points in space exhibit red shift.
  6. Nov 11, 2009 #5
    would it be fair to say that it would be almost impossible to see an object at the exact "left" and the "right" ?

    also, the "left" and "right" would actually be on a circular radius of distance from earth to point X with center at point x.

    so chances are we are always seeing an object that is either a bit farther away(behind) or nearer(in front) when compared to the distance earth is to the point X.

    is this possible?
  7. Nov 11, 2009 #6
    How would it explain structures forming and staying together? This should also be observable more locally wouldn't it?
  8. Nov 11, 2009 #7
    No. It's not. Once you come up with a theory, you look for things to disprove the theory, and I don't see how you can get the velocity fields to work.

    The way that science works is that if you have a theory, and you find that people haven't observed enough to strengthen or disprove it, then you tell the observers where to point their telescopes at. One fact is that everything seems to be receding away, which doesn't make sense if we were all converging to a point.
  9. Nov 11, 2009 #8


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    It doesn't make a difference if the objects are just a little bit further or nearer to point x. The point is that there would be a pattern in the shift depending upon which direction you were looking. Looking straight away or towards X would give red shifts. Looking at objects the same distance way from X would give blue shifts. (objects on a shrinking surface of a sphere get closer together. Looking at angles between these two extremes give something in between.

    We don't see this pattern. What we see is that no matter which direction we look, distance and red shift match.

    In addition, even looking straight in or straight out in your model wouldn't match up with what we see. The difference in speeds between objects a given distance closer to x than us would be greater than the difference between us and objects the same distance away in the opposite direction, which in turn would lead to a larger red shift for the "inward" objects.

    The final upshot is that that there is no way to make this model fit actual red shift measurement.
  10. Nov 12, 2009 #9
    hmm... i see...

    so its still puzzling after all
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook