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Questioning the big bang theory.

  1. Oct 27, 2007 #1
    The big bang theory states:

    That at one time, everything that is known of our universe was once at a single point before it commenced "The Big Bang".

    Correct me if I'm wrong but, that means that every single particle in our entire universe could have been seen at some point in time after the big bang.

    The question: How are we finding new Galaxies, and clusters of galaxies, that we have never seen before, because the light from those galaxies were just getting to us?

    If the big bang theory is true then, we should have always been able to see every particle at any point in time. They would have just been getting farther away, but the light reflecting off of them would still be visible at a point in time.

    I will clarify if needed. A reply is much appreciated.
     
  2. jcsd
  3. Oct 27, 2007 #2

    cristo

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    Actually, it doesn't. The big bang theory merely says that the content of the universe was, at an earlier time, much more dense than it is now.
     
  4. Oct 27, 2007 #3

    Wallace

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    Yep, the Big Bang is popularly thought of as an explosion that happened at some point however this is not what the scientific theory of the Big Bang suggests.

    Try having a look atthis FAQ, it may help you. Any more questions you have feel free to ask!
     
  5. Oct 28, 2007 #4

    Chris Hillman

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    Suggest a good textbook

    Not true. This is a very common misconception, and I can understand how one might get this impression from reading popular books, but it seems to me that you should really study enough physics/math to make a credible attempt to learn what the Big Bang model is really all about, before you attempt to "criticize" it!

    This issue is addressed in many textbooks. I suggest that you study the very readable undergraduate textbook by D'Inverno, Understanding Einstein's Relativity, which has a good survey of the basic cosmological models (including FRW dusts with nonzero Lambda).

    No, that's completely incorrect. See D'Inverno. If that book proves too hard, try the excellent popular book by Weinberg, which predates "nonzero Lambda" but addresses your confusion about horizons.
     
    Last edited: Oct 28, 2007
  6. Oct 28, 2007 #5

    Wallace

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    Give the chap a chance please! He's asked a question, not launched a huge criticism! We can't expect everyone to have read textbooks before posting on these forums, what would be the point? Please try and be more welcoming and friendly to new people.
     
  7. Oct 28, 2007 #6

    Chris Hillman

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    I wouldn't have objected if James had in fact asked a question rather than by making misstatements. His reponse will determine whether I over-reacted to his initial post and also whether you over-reacted to mine.

    Did you perhaps overlook the unfortunate title which he chose? This could be read as suggesting that his intention was to challenge contemporary mainstream cosmology, not to ask a question about what it says. It is also true that he asked for corrections--- which I provided.

    I agree that it is sometimes acceptable to ask a question in PF before reading a textbook, but I would disagree with any claim that it is never acceptable to respond by recommending an authoritative, clearly written, and widely used textbook!

    Hopefully the OP and newbie lurkers can take this as a lesson in some issues to think about when composing a post to this forum!

    Now let's move on.
     
    Last edited: Oct 28, 2007
  8. Oct 29, 2007 #7

    Chronos

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    Welcome to PF, Egan! Wallace and Chris are professionals and their advice is impeccable. My fumbling analogy is: The BBT suffers from pop culture disease. It was neither 'big' or 'explosive'. It resembles a punctured balloon as viewed from a point on the receeding edge of the puncture.
     
  9. Oct 30, 2007 #8

    Chris Hillman

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    Who me, trouble the waters? (Jn5:4)

    Actually, in physics I am an amateur, but hopefully a knowledgeable one whose advice is at least worthy of consideration :wink: Certainly I claim to know how to crank predictions out of gtr and some other classical field theories.

    James, you might have noticed my frustration in the past few days with some other newbie posters. If I did indeed misunderstand your intentions, please don't feel discouraged from posting at PF again!
     
    Last edited: Oct 30, 2007
  10. Nov 5, 2007 #9
    "Looking through a telescope .. is looking back in time. Light takes all that time to reach us.. etc."
    I was/am so confused! "Look at the galaxy out there. Let its red shift let you know how fast its moving away. Everything moves away. All is expanding, and we can figure back to when it was all close together".

    I never thought the galactic mass could get too close, much less a point, but I did think that any light from events near the time would at least travel away faster than the rest of the masses we are are made of could move.
    Now that is (sort of) reassuring, but not enough. I read the FAQ also. Relativity? When we look through telescopes, we look at events displaced far from us in space, and from a time in the past which we figure by how long the light must have taken to get here, given we assumed by the red shift that the bits moving fastest must have got further. Whatever they did, they were never moving anything but away from the event, and quite slow compared to the light that describes their (violent?) origins..

    This is why I find it hard to understand when we hear of "looking back to near the time of the big bang" I fully expect to get the concept resolved soon. There is lots to read here. :smile:
     
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