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

Effect of negative gravity on time

  1. Dec 3, 2012 #1
    Current theory of the big bang postulates that there was a very period when gravity reversed and the result was what we term the 'big bang'.

    Assuming this to be true, negative gravity would cause time to be a function of i. -- 1/2 A = D / (T x T) If A is negative then either D or T squared also has to be negative and, since it is unlikely that D is negative then T squared must be negative. The square root of a negative number must be a function of i. Since the velocity of light = D / T, what does the velocity of light become if T is a function of i ?

    Any comments?
     
  2. jcsd
  3. Dec 3, 2012 #2

    bapowell

    User Avatar
    Science Advisor

    Could you please provide a reference for this claim?

    EDIT: Also, you might want to define the terms in your mathematical expression.
     
  4. Dec 3, 2012 #3
    I first read about it in Brian Greene's "The Fabric of the Cosmos". It referred to discoveries mad by Alan Guth in 1979.

    In my mathematical references, 'A' refers to acceleration, in this case by gravity; 'D' refers to distance and 'T' refers to time. I wasn't able to figure out how to show exponentials.
     
  5. Dec 3, 2012 #4

    Drakkith

    User Avatar

    Staff: Mentor

    I've never heard of anything saying that gravity reversed. Perhaps it wasn't meant to be a rigorous statement of the gravitational force in the early universe, but simply a descriptive way of saying what happened? If you are talking about inflation, then I don't think gravity was responsible for that.
     
  6. Dec 3, 2012 #5
    Drakkith:
    I quote: ". . . a supercooled Higgs field . . . exerts a repulsive gravitational force that drives space to expand." And, "Guth was able to estimate the energy and negative pressure contributed by the Higgs fields. . . and the answer he found was more than 10 (exponential 100) times larger than the value Einstein had chosen. . . . and so the outward push supplied by the Higgs field's repulsive gravity is monumental . . ." And, ". . . we have a phenomenal, short-lived outward burst. In other words, we have exactly what the big bang theory was missing: a bang, and a big one at that." And, ". . . the inflaton field generated a gigantic gravitaional repulsion that drove every region of space to rush away from every other . . .The repulsion only lasted 10 (-35 exponential) seconds but it was so powerful that even in that brief moment the universe swelled by a huge factor . . . the universe could easily have expanded by a factor of 10 (30, 50 or 100 exponential) or more."

    By the way, the proof that the Higgs boson exists is what was proved by CERN recently.
     
  7. Dec 3, 2012 #6

    Drakkith

    User Avatar

    Staff: Mentor

    The Higgs Boson has not been proven to exist yet. They are not confident enough to label it the Higgs quite yet.

    And From Wiki on Inflation:

    In the early proposal of Guth, it was thought that the inflaton was the Higgs field, the field which explains the mass of the elementary particles.[36] It is now believed that the inflaton cannot be the Higgs field[64] although the recent discovery of the Higgs boson has increased the number of works considering the Higgs field as inflaton.

    So we don't really know what powered inflation. It could be gravity, it could be something else. It will be interesting to see how this develops if the Higgs turns out to be real.
     
  8. Dec 3, 2012 #7

    bapowell

    User Avatar
    Science Advisor

    Inflation is driven by a special kind of energy density with a negative pressure; it leads to an accelerated expansion of space, identical to the current accelerated expansion. This is sometimes referred to as repulsive gravity, but it's not "negative" and there are no negative energies running about. The way that inflation is generally implemented in basic models is as scalar field with very special properties; indeed, the Higgs field is one such scalar field, but the Standard Model Higgs was shown to not have the requisite properties to drive inflation back in the 80's. That's not to say that something like the Higgs is not ultimately responsible, but we simply don't know yet.

    We need to sit tight and stay tuned. Drakkith is right -- the Higgs has not been proven to exist yet, but I think we're on the right track. Even finding a fundamental scalar at the LHC would be huge, as it would be the first ever discovered and it's an essential ingredient in many inflation models.
     
  9. Dec 3, 2012 #8

    Drakkith

    User Avatar

    Staff: Mentor

    Can you imagine them going "Hey...this isn't the Higgs..." after more analysis. That would be exciting!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Effect of negative gravity on time
Loading...