Beginner questions: big bang impossible in normal physics? Do black holes die? Etc..

Discussion in 'Astronomy, Exobiology, & Cosmology' started by krystof, Jun 1, 2008.

  1. krystof Registered Member

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    Hello. I am just now in the process of viewing all the 'creation of the universe' documentaries I can find. I have some questions about the Big Bang.

    1. Is the Big Bang possible under current laws of physics?

    I understand that before the Big Bang, there was supposedly no such thing as space or time. The current laws did not apply. And some scientists may be making some serious proposals about what laws did apply. However, am I correct to say "The big bang could not happen again in the current reality..."?

    I.e., to my understanding, the biggest explosion that we know about is that which creates a black hole. I.e., if an explosion is large enough to create the universe, then wouldn't all that matter be unable to escape, under current laws?

    :idea: 2. However, some matter and energy does escape from every black hole. So perhaps the center of the universe is a black hole, and all the so-called 'known universe' is perhaps a relatively small amount of matter and energy that managed to escape...?

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    3. According to an older documentary (Hyperspace with Sam Neil) black holes once formed are destructive vaccuums that never die. Is this still the current opinion of science? (I seem to recall hearing in another documentary that black holes ultimately recycle creative energy--and thus might have something to do with the creation and possible re-creation of the universe--but perhaps I am mistaken..?)

    :huh: 4. According to a recent documentary series (The Universe) we have no idea where the center of the universe is. Not even the general direction. I find this hard to swallow. We can see all galaxies moving apart--and we determine that they are moving apart faster--and we support the Big Bang theory by saying that all galaxies are determined to have originated from the same point--but we have no idea where that point is...? What am I missing here?
     
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  3. draqon Banned Banned

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    My understanding of black holes was that when a black hole has no matter to process in itself and no longer radiates x-rays, it ceases to exist.
     
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  5. Forceman May the force be with you Registered Senior Member

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    When a black hole dies, the trapped matter is said to be transported to a parallel universe, according to Stephen Hawking, which conjured the possibilty of wormholes.
     
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  7. James R Just this guy, you know? Staff Member

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    krystof:

    Of course. The Big Bang theory is based on our current best physical theories.

    Since time didn't exist, the words "before the big bang" don't really make any sense.

    The big bang created the universe, so you're essentially asking whether the big bang could occur again in our universe. The answer is no, because our universe already exists.

    Black holes are caused by gravitational collapse, not explosions, though perhaps you're thinking of the supernova explosions that precede the formation of black holes.

    The fundamental forces of nature were "fused" at the big bang, in a way that meant that gravity alone could not stop the initial expansion.

    There is no centre of the universe.

    Black holes gradually, over billions of years, evaporate, releasing energy through a process known as Hawking radiation.

    Think of the universe like a loaf of raisin bread being baked in an oven. As the bread expands, all the raisins move away from one another. The bread is the universe; the raisins are the galaxies. Now, your question is like asking "which raisin is at the centre of the loaf?" From the general expansion, there's no way to tell. And we can't see any "edges" of the loaf, either.


    draqon:

    Yes. When all of the mass of a hole has been radiated away via the Hawking process, the black hole will evaporate.


    Forceman:

    There is no evidence at all that any "parallel universes" exist. However, nobody (including Stephen Hawking) knows what happens at the centre of a black hole.
     
  8. Reiku Banned Banned

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    No it doesn't.

    This would violate the information paradox, so Hawking has retracted his statement, and says nothing can move through black holes and enter other universes.
     
  9. krystof Registered Member

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    Thank you everyone for your help!

    I have been browsing the Wickipedia and that also has helped, but also raised one or two other questions, as follows.

    1. The "Hawking Radiation" theory of black holes is that they will last much longer than anything else, but will eventually evaporate from slow leakage based partly on 'Heisenberg uncertainty theory'--according to Wickipedia. This is currently unproven but seems a dominant theory which scientists are hopeful of observing directly.

    2. Super-massive Black holes are nonetheless often described as 'engines of creation' due to the formation of 'accretion discs' resulting from certain limits on the speed at which a black hole can consume. The surrounding matter gathers into a disc and can become a Quasar or similar expression of the most powerful energy-producing forces in the universe.

    3. There seem many ideas but no dominant theory about how the big bang actually happened. In fact, the big bang is so problematical that it was not fully accepted until the 1960's, due to the accidental discovery of background microwave radiation. I.e., the acceptance of the big bang is based on overwhelming circumstantial evidence, but only the 'faith' that we may someday work out how it actually happened. (This still leaves my question unanswered: whether or not the Big Bang theory might carry direct inherent contradictions to the known laws of physics.)

    4. Q: Are we ever likely to determine which way is the center of the universe? I assume James R. is right about not knowing the center, because he seems right about everything else. But, do we not know this because such knowledge is impossible, or rather because we have not yet observed enough of the universe to make this determination? It seems to me that if we observe enough of a loaf of raisin bread, we should be able to roughly determine its center--or at least which raisins were 'relatively' nearer to the center than others, based obviously on the direction they are moving.

    5. Q: How certain is the 'point of singularity' idea about the original size of the universe? On the one hand, I am finding only numerous 'incomplete hypotheses' about the nature of the big bang. But on the other hand, especiall in the documentary The Universe, several noted scientists speak with certainty that the universe began at the size of an atom. Nobody clarifies how they arrived at this conclusion. In the Wickipedia there is some reference that this is derived from quantum physics. However that is way above my head. I would just like to know if this is 'just another idea'? Or is this 'point of singularity' theory for the original size of the universe strongly accepted on a level with the big bang theory itself?

    6. Does anybody sincerely believe that the Big Bang theory is harder to believe than the Big God theory? I would agree that believing in the Big bang is not easy. I find no reason in science to disbelieve that the basic nature of existance is spiritual, not physical. However, what boggles my mind is people who say with a straight face, "I can't believe a big bang just happened." So instead, they claim it is much easier to believe that God just happened. In order to agree with them, I would need to believe that God is more simple than a rock. In my opinion, the very definition of God implies something at least equivalent to a complex organism. So I would list the following as my own personal order of belief.

    a) Least difficult to believe: bunch of matter happend to be there and happened to explode.
    b) Much harder to believe: somebody named God happened to be there and happened to decide to create the universe.
    c) Hardest of all to believe: that anybody would find the existance of God which they have never seen easier to believe than the existance of inanimate physical entities such as they see all the time.

    (I personally do believe in God but I think it is drastically selling him short to claim he is either 'easier to believe' or 'easier to understand' than the Big Bang theory.)
     
  10. blobrana Registered Senior Member

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    >>3
    One main theory involves something called symmetry breaking. Quantum fluctuations (a random event) in a highly ordered multidimensional universe caused it to break up into lower energy/disordered states creating separate space, time, forces and energy.

    >>4
    yes, James R. is right.
    It is a bit like driving to the centre of the earth. It doesnt matter which road we take, or how far or fast we go. We are stuck on a surface. The centre is in another `direction` (dimension) that we cannot go to.

    >>5
    The `singularity` has a minimum size of about 10^-43 cm. (at that size space and time smear together, and out normal physics/maths just gives meaningless results/ fails.)
     
  11. Cyperium I'm always me Valued Senior Member

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    Hello, about the center of the universe:

    Everything moves away from everything else, so if we would measure everythings movement we would conclude that the center of the universe is the observer measuring, since everything moves away from you.

    So instead of saying that there is no center of the universe, we could better say that the center of the universe is everywhere, the Big Bang happened everywhere you know

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    if it happened within a space there would be a center, but it didn't happen within a space and thus happened everywhere.

    Perhaps instead of saying that the center is everywhere, we could say that the center is at the observer. It could be that there is no other center than an subjective one. I'm currently trying to see if I can get around that in another thread, but it's unlikely.
     
    Last edited: Jun 8, 2008
  12. machiaventa Registered Senior Member

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    The Mind is a Powerful thing

    The ancient german Philosiphers believe the Universe came into existance through the power of the continuim otherwise refered to as the "Q". They believed a Creator Being thought it into existance purely through the power of the mind. Even with our meager use of our brains we have learned that if you can imagine it sooner or later it will exist if one wants it bad enough. All things are possible.

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    Machiaventa Speaks
     
  13. nietzschefan Thread Killer Valued Senior Member

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    How do we know the "Big Bang" was really not just a comparatively super large Quasar? I mean comparatively, despite our not being able to detect anything else that may have occurred or be occuring, outside this "local", "Big Bang" event.
     
  14. nietzschefan Thread Killer Valued Senior Member

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    Comon beginner's not welcome here?
     
  15. James R Just this guy, you know? Staff Member

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    A quasar is an "active" galaxy, with a large black hole at its centre that emits a lot of energy (well, the black hole itself doesn't emit, but its accretion disc does). Quasars keep emitting energy over a long period of time.

    In contrast, the big bang was a one-off explosion of space and time.

    A quasar is an object that is found in a pre-existing spacetime. The big bang was the creation of spacetime itself.
     
  16. James R Just this guy, you know? Staff Member

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    krystof:

    It is possible that we may discover fundamental problems with the current big bang theory, especially once we develop a quantum theory of gravity. The best we can say right now is that today's known physics seems to account for what we observe fairly well, down to tiny fractions of a second after the start of the big bang.

    The raisin bread analogy is an imperfect one. A raisin loaf has a centre and it has edges. In contrast, our universe doesn't seem to have any edges. Our current best theory says that the universe is actually infinite in extent.

    A singularity, technically, is a mathematical idea. It is a point at which certain equations "blow up", giving apparently unphysical results. Generally, the presence of a mathematical singularity in a physical theory is a sign either that (a) there is something wrong with the theory, or (b) that the theory is being applied at a point where its basic assumptions aren't applicable.

    When people take about the singularity at the centre of a black hole, or the big bang singularity, what they really mean is that the mathematics breaks down there. Physicists clearly understand that current theories are insufficient to describe what happens at the exact centre of a black hole, or at the moment of the big bang. Both those points involve very strong gravitational fields acting on a lot of matter at very high density. A complete description of such a situation requires both relativity and quantum physics, but the problem is that nobody is sure exactly how to combine quantum physics and relativity under these conditions - yet.
     
  17. kaneda Actual Cynic Registered Senior Member

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    krystof.

    1. The big bang idea is nonsense. A number of professional astronomers do not accept it. It's only support is red shift and the CMB and they have alternative explanations.

    2. When a large enough star runs low on energy, usually after a super-nova, it collapses into a black hole. Most/all galaxies have black holes at their centre. The largest one found so far is 18,000,000,000 times the mass of the sun. Nothing escapes a black hole it is said but gravity does and they can have huge magnetic fields. Black hole jets are caused by magnetic fields whipping up infalling matter (which does not cross the event horizon).

    3. The idea, and it is just an idea, is that black holes can lose energy where with a twin particle, one falls in and one escapes. Rubbish.

    4. The big bang idea is like a balloon blowing up, so no centre. However it is a stupid idea so there may be a centre of the universe. We only very recently The idea that everything is moving away from everything else except where local attraction, even in some unlikely remote clusters, keeps them together. It is not a logical idea since we can see back almost to over 13,000,000,000 years ago and see no universe where everything is tightly clumped together. Dark energy is science's answer to creationism.

    Less than a year ago, we found a billion light year wide hole in the universe where there is virtually nothing. Earlier this year we found the super-massive black hole I mention above, several times the previous record holder. There is still a hell of a lot we don't know about the universe.
     
  18. kaneda Actual Cynic Registered Senior Member

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    krystof. As to the big bang; evidence for a multiverse, branes, singularities, FTL inflation, etc is the same as for creation. Wishful thinking. However just because we don't know how everything started, claiming a super-magician said the magic word and started it off is just making it up. The Genesis story is probably less than 3000 years old and bears many resemblances to the older Egyptian creation myths which many believe they were copied from. Certainly the ten commandments were stolen from the Egyptian Book of the Dead..
     
  19. James R Just this guy, you know? Staff Member

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    A very small number.

    You might want to google "big bang theory evidence". It's support is much more than just that.

    We're supposed to take your word for it that it is rubbish... why, exactly? Physicists don't think it's rubbish.

    Again with the gut reaction! "My gut tells me it's stupid, and I haven't bothered to learn about it, so it must be stupid."

    Hmm...

    Not very persuasive.
     
  20. Forceman May the force be with you Registered Senior Member

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    How else could you explain the centripetal force of the stars of the spiral arms of spiral galaxies, disturbance of light propagation, radiation emission, which also accounts for the chaotic conditions associated to the influence of extrem space-time curvature on the stars near it, in turn colliding them causing them to explode violently at rapid pastes.
     
  21. AlphaNumeric Fully ionized Registered Senior Member

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    How is it you've been a nay sayer for the BB for years and yet you do zero research into it? As James R points out, you only have to type "Big Bang Evidence" into Google and you find more. The decrease in galaxy number and the relative abundance of particular light elements being two big ones.

    How do you plan to refute evidence for a theory you don't even know the evidence for? The only argument you hurt is your own.
    Why? We have no experimental evidence to doubt it because the theory is it based on, quantum field theory, has passed all tests. The test to Unruh radiation will be done soon.

    We've established in the past that you don't know the details of general relativity and how they pertain to the BB or black holes.
    Why is it rubbish? The non-static nature of space-time is a natural consequence of relativity (hence prompting Einstein to put in a non-zero cosmological constant into the equations), it naturally leads to a situation where all places in the universe seem to be the centre of expansion and we have observational evidence for it.
    http://en.wikipedia.org/wiki/Big_Bang#Galactic_evolution_and_distribution

    Where's your evidence?
    Which translates to "There's a lot about the universe we don't know so all our models for it must be wrong, even conceptually".
    There is no evidence for multiverses or branes. You create strawmen through poor research and ignorance.

    And you provide nothing but "In my opinion it's stupid so it's wrong". And you also demonstrate you don't do any research into this at all. Well done. You typify crank ignorance.
     
  22. kaneda Actual Cynic Registered Senior Member

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    AlphaNumeric. I explained to you again and again on physorg forums why the BB was wrong yet you failed at any time to show me wrong. I provided ample evidence to show it and you wrong.

    You have a steep incline a thousand miles deep. You put two ping pong balls next to each other. One rolls down hill, the other rolls uphill. Hawking radiation explained.

    A certAiN fool said that a living person could enter a black hole alive till I proved you wrong.

    As I have pointed out endlessly to you, expansion needs a four physical dimensional hypersphere (right, Nick?). Show me that fourth physical dimension and explain what is inside and outside the hypersphere since the universe is only it's 3D skin.

    We have seen galaxies 13,200,000,000 years old. They are not distorted in size. So we see back further and we see a CMB that covers everywhere. We see it as it was shortly after the BB, not as it is now. we see it at it's original size. It is also the same temperature as space not far from our sun's heat. 2.7K. Amazing.

    As I pointed out elsewhere, a billion LY hole in the universe. Black hole of 18 billion solar masses. Walls of galaxies, one of which has 12,000 times our own galaxy''s mass. All in less than 14 billion years.

    I was just using some of the dogma of the big bang which does not exist, like dark energy. you are like a creationist, using a god of the gaps. We don't know how the universe began so "it must be a big bang" which caused it. evidence: the universe is here, isn't it?

    Lack of shadows on the early universe showed the BB wrong. A guy recently traced many of the measurements on WMAP to our own galaxy! Can it get any worse?

    As I have pointed out to you so many times before, you have zero ability to think of anything new. You just parrot text books and internet sites, like the wiki (doh!). I don't know how you think you're suddenly going to grow a brain when you try for a job in research.
     
  23. kaneda Actual Cynic Registered Senior Member

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    I tried putting it all together. It still does not make any sense. Just babble!
     

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