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Leaking gravity?

  1. Mar 1, 2005 #1
    I was perusing the sci/tech articles at MSNBC and came across this article:


    The physicist in the article suggests that the acclerated expansion of the universe is caused by gravitons "leaking" into extra dimensions (borrowing from string theory). This hypothesis does not introduce the concept of dark energy, and towards the end of the article it is suggested that a test could be conducted to measure whether gravity really is leaking using the mirrors on the Moon.

    What do you think? With our present tech capabilities, would we be able to use the Earth-Moon system to measure the leaking of gravity? I'm a bit skeptical, but I really don't have the technical specifics necessary to construct a good evaluation of this idea.
  2. jcsd
  3. Mar 1, 2005 #2


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    Given we have not yet detected gravitons or any extra dimensions, I would say it is pretty speculative.
  4. Mar 7, 2005 #3
    FYI the idea that gravity leaks from a dimension to this one comes from some crackpot string theoriests to explain why gravity is so weak... I'm not even going to go into it...

    Now this article is talking about gravity leaking from this dimension to another... So its reverse now I guess...
  5. Mar 7, 2005 #4
    I think gravity is strong. :P
  6. Mar 7, 2005 #5
    not compared to the other three forces!
  7. Mar 8, 2005 #6
    maybe I'm too simple minded,not knowing alot of advanced math,but if matter were to be viewed as a hole in space/time,and space/time flowed into the hole then there would be currents flowing into all the holes and the dencer the matter, the stronger the flow into the hole and the current affected by that. As the currents move,the holes move along with the flow and so that would explain why matter seems to attract matter. Just another one of my strange thoughts!
  8. Mar 8, 2005 #7


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    I've always disliked the terminology of "gravity being weak compared to the other three forces", which generates more smoke than light.

    Typically, this is done by comparing the gravitational force, electrical force and strong force associated with a pair of quarks or some such atomic scale comparison. But, of course, in some situations (e.g. in astronomy) gravity is a dominant consideration while the impact of the other forces is negligable, while in other situations (e.g. within an atomic nucleus), the "strong force" dominants in its effect over electromagnetic force and weak force and gravity, and between atoms in molecules, electromagnetic forces are typically dominant while the two nuclear forces and gravity are insignificant by comparison.

    Outside of a particular context, a statement that once force is stronger than another is pretty meaningless. (BTW, I was feeling uninspired and didn't feel like throwing in a dominant weak force example, although, of course, they exist too).
    Last edited: Mar 8, 2005
  9. Mar 8, 2005 #8


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    ohwilleke, did you ever try picking up a needle with a toy magnet. There was that little bundle of magnetism pulling on one side and the whole great earth with its gravity pulling on the other; which one won?

    Gravity is weaker than the other forces when sources are comparable. The property that makes gravity strong in daily life is that it is long range and only positive. Since it is long range we feel it at our scale unlike the strong and weak forces which are short range for different reasons. And since there is no antigravity to cancel it it can build up by clustering sources. To ignore these different properties in classifying strengths just doesn't make sense.
  10. Mar 8, 2005 #9
    nevertheless, my statement is still correct! gravity is the weakest comparitively. compare the kinetic energies released from the gravitational infall of a body to earth with the kinetic energy released when an atomic bomb is let off containing the same amount of mass as the infalling body.

    I think you will find slightly differing answers!

    you are correct in what you are saying, however when making a comparison, you should make it a fair one.
  11. Mar 8, 2005 #10
    I believe that Gravity and Electromagentism are the same forces. But I won't get futher into my reasons for the sake of the forum.
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