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Photons, weight and force

  1. Feb 3, 2009 #1
    If photons have no weight,how can an amount of 2.5kg of sunlight fall on earth each second??http://www.newton.dep.anl.gov/askasci/phy00/phy00644.htm Also, what would be the accumulative effect of all the light/energy emitting objects in the known universe over 13+billion years and its effect on the fabric of space? What percentage of this radiation is from original cmb and what percent from the more recent 13+ billion years of stellar radiation? Is this the force responsible for the resumed expansion of the universe some 5 billion years ago?
    I cannot wrap my head around graviton strings pulling from infinite distance. Is it possible that matter and its apparent gravity is the lesser of forces and space is pressurized at a quantum level
  2. jcsd
  3. Feb 4, 2009 #2
    You link explains the answer to your first question much better than I could...

    As for your other questions you'll need to be more specific and clearer. You seem to be suggesting the Universe stopped expanding and resumed expanding 5 billion years ago.
  4. Feb 4, 2009 #3
    reasonableman see:


    I am suggesting the possibility that the continued expulsion of energy in all its forms from the known sources of matter is the driving force responsible for the accelerating expansion of the universe, filling space like air in a balloon. A balloon without containment. We can all agree that this is a huge amount of energy and none is lost, and little reabsorbed. We are after all, bubbles in space, and any force pushing on suspended objects will have an effect. And this sea of energy pushing on all objects uniformly from all directions is what we witness as gravity. Hence, what we are witnessing as gravity between two objects is a disruption in this river of energy creating an eddy current (if you will) or area of lower pressure between the two body's drawing them into this relative vacuum between them. The closer the objects the stronger the force of this disruption or eddy current drawing the two objects together.
    Sorry I just don't get gravitons. I can relate to vacuums. particles lining up infinitely to fill a void, but strands pulling from infinite distances between objects?
  5. Feb 4, 2009 #4


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    This is rather puzzling. You are objecting and putting all this effort on something that we don't even yet know to exist?

    You need to understand something very clearly, which is the nature of quantum field theory. What is being theorized here is that, IF the other interactions (EM, Weak, and Strong) can be described via QFT, and gravity is another such interactions, then if we apply QFT, then there has to be a mediating particle for this interaction, which we call "gravitons". It hasn't been discovered, it is still highly hypothetical, and no one is betting his/her house on it!

    As for "vacuum particles lining up infinitely to fill a void", how come you have no problems with photons doing the same thing to mediate EM interactions? If you buy QFT in one scenario, why is it difficult to accept for another scenario?

  6. Feb 5, 2009 #5
    I still don't see how this can be responsible. The expansive 'force' or whatever it is has to have a drop off slower than 1/r^2. Because gravity has that drop off and this 'expansion force' supposedly dominates over large distances. However radiation pressure also drops off at 1/r^2 as it's a function of irradiance.

    Also photons are bosons, so don't interact with one another, so can't form an isotropic pressure like a gas.
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