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Before-Big Bang

  1. Sep 14, 2010 #1
    Big bang suggests that there was only a concentrated mass.was there no space?If there was no space where did it come from?[i mean what makes space?].time also started after big bang.how did it start?
    Don't u guys think there's somethin missing in this theory?
     
  2. jcsd
  3. Sep 14, 2010 #2
  4. Oct 8, 2010 #3
    Asking a physicist what happened before the big bang is like asking whats north of the North Pole.
     
  5. Oct 8, 2010 #4
    I often hear this, and I think it's a miscommunication about what is meant by "before." Perhaps a better way to phrase it for the pedantic physicists is "What, if anything, caused the big bang to occur."

    A good follow-up question would be "Is that something we can even find an answer for?"
     
  6. Oct 9, 2010 #5

    Chronos

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    The short answer is 'No'. BBT is only relevant after the first tick of planck time. It does not attempt to explain initial conditions. There are any number of speculations about what caused the big event. I'm not aware of any that are testable.
     
  7. Oct 11, 2010 #6
    When physicists says there is no before the big bang I think they are speaking prematurely. I think a better answer is, our current model of cosmology, General Relativity implies a begning of time at the big bang. It also implies a whole host of infinite values for the universe at this singular point. One might take this as an accurate description of the universe or more likely a sign that our models simply break dwon at the this point and we need a new theory of (quantum) gravity.
    Many attempts to formulate quantrum theories of gravity imply a pre big bang universe, but at the moment we dont know if any of them are correct, maybe none of them are . There are also some other possibilities of a "before the big bang scenario" such as Roger Pensrose Conformal Cyclic Cosmology and eternal inflation. I have made a short video discussing these , you can see it here:

    http://www.youtube.com/user/skydivephil
     
  8. Oct 11, 2010 #7

    Chronos

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    Did you forget to edit out the crap part?
     
  9. Oct 11, 2010 #8
    What about CMB? There is on-going studies.
     
  10. Oct 11, 2010 #9
  11. Oct 11, 2010 #10

    Chronos

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    What about CMB? That was 380,000 years after the big event.
    Sky, your previous link was irrelevant, and your latest link also appears to be off topic. Thus far I perceive you have nothing to contribute.
     
  12. Oct 11, 2010 #11
    The model suggests that new universes could be created spontaneously from apparently empty space. The WMAP is collecting data, and so far last I heard, detailed measurements made by the satellite have shown that the fluctuations in the microwave background are about 10% stronger on one side of the sky than those on the other.

    http://map.gsfc.nasa.gov/universe/bb_tests_cmb.html
     
    Last edited: Oct 11, 2010
  13. Oct 11, 2010 #12
    Apologies,

    I should have explained what the meaning was in regards to it being 10% stronger on one side, or the universe is "lop-sided" - The significance of this would be if these fluctuations represented a structure left over from the Universe that created our Universe.
     
  14. Oct 11, 2010 #13
    The topic is before the big bang. My link directs people to peer reviewed papers that discuss the possibility of pre big bang scenarios. No one here has mentioned Loop Quanutm Graivty or Penrose's Conformal Cyclic. The link does does do that. whilst at the same time not endorsing any of these ideas.
    My point is that its often said there's no time before the big bang, yet that is a premature statement. We need to get a quanutm theory of gravity to be able to answer these questions. At the moment we dont have one, we have a couple of candidates which some pople think are promising and if true imply a pre big bang era, but that moment we dont have anyhting thats verified by any data. Now which bit of this do you think is irrelevant or incorrect?
     
  15. Oct 11, 2010 #14
    That statement is now widely accepted by many scientists as "We don't know"....
     
  16. Oct 11, 2010 #15
    i think thats very reasonable, yet many people will still say there is no possibility of anything before the big bang and those two statements are not the same.
     
  17. Oct 11, 2010 #16
    Correct. It sometimes boils down to ignorance, but as you can see from my posts above, there is an on-going "theory" if you like into what was before the big bang.
     
  18. Oct 11, 2010 #17


    /thread
     
  19. Oct 11, 2010 #18
    And this means?
     
  20. Oct 12, 2010 #19
    Last edited by a moderator: Apr 25, 2017
  21. Oct 12, 2010 #20

    alt

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    Unfortunately, the videos are .. "Not available in your area"

    But the following front page comments are interesting;

    Neil Turok who runs the Perimeter Institute for Fundamental Physics research in Canada, is so disillusioned with cosmology’s Big Bang, that he’s developed m-theory which holds that there was no bang at all - ‘simply’ the collision of three dimensional universes like ours arranged on parallel membranes. The collision takes place in a fourth dimension that we’re not aware of, but spells the end of the current universes and the beginning of a new one. But no bang.

    Sir Roger Penrose has changed his mind about the Big Bang. He now imagines an eternal cycle of expanding universes where matter becomes energy and back again in the birth of new universes and so on and so on.
     
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