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Thread: Did the Universe appear from an infinitely dense, infinitely small point?

  1. #31
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    There's a very small amount of room at this point - everything at this singularity experience spacetime appear between each object - as the universe expanded, it cooled enough to allow the dimensions of spacetime as we currently understand it exist.

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    Quote Originally Posted by Aethelwulf
    To believe in a breakdown of the theory is so far, a personal choice.
    Nope. Your concept of "singularity" is incorrect. It means ERROR, you have gone out of bounds. You can be certain that the following professor never taught that "the universe was once an infinitely dense, infinitely small point."


    "We mentioned that the FLRW cosmology begins with a singularity. This is a much more serious breakdown than a flat tire or a cracked engine block. It is, in fact, a physical impossibility -- a region where the laws of physics break down altogether and even spacetime comes to an end." -- Tony Rothman


    What does it mean for something to be "infinitely dense"? How do you make meaning out of this? It's meaningless. It's not a matter of personal choice.
    Everyone is entitled to his own opinion, but not his own facts.

  3. #33
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    Quote Originally Posted by Cougar View Post
    Nope. Your concept of "singularity" is incorrect. It means ERROR, you have gone out of bounds. You can be certain that the following professor never taught that "the universe was once an infinitely dense, infinitely small point."
    No I really mean that it is a personal choice. Some of us embrace singularities - I don't embrace all singularities, just this one. I like it, and I know many people that like it also. I understand exactly what a singularity is, please don't partonize me. I meant this really as it sounds - I personally do not see it as a breakdown in theory.

  4. #34
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    You have such a point as the origin of the mainstream model the BB.
    Doesn't matter how many times you say it - not true. The mainstream BB theory stops short of a point as origin.

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    Quote Originally Posted by Shaula View Post
    Doesn't matter how many times you say it - not true. The mainstream BB theory stops short of a point as origin.
    Well, I've already established with another poster here that essentially we have dealt with BB appearing from a point is in fact what current theory says because ''we have attached it to have this significance''. Anything you may say is clearly not maintream - or how we traditionally describe the BB.

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    Quote Originally Posted by Aethelwulf View Post
    Well, I've already established with another poster here that essentially we have dealt with BB appearing from a point is in fact what current theory says because ''we have attached it to have this significance''.
    No; Earlier attempts at the theory said that.
    It's been revised by Hawking

    Hawking later revised his position in A Brief History of Time (1988) where he stated "There was in fact no singularity at the beginning of the universe" (p50). This revision followed from quantum mechanics, in which general relativity must break down at times less than the Planck time. Hence general relativity cannot be used to show a singularity.

  7. #37
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    Quote Originally Posted by NEOWatcher View Post
    No; Earlier attempts at the theory said that.
    It's been revised by Hawking
    Read my Times below Planck Time thread in technology.

    I have debated this topic concerning Hawkings idea's and they are mostly circular. I don't find it all too surprising Hawking has revised his beliefs. Penrose who wrote the singularity theorems with him, now believes in a cyclic universe theory.

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    The are just attempts on getting QM's to describe something - just because they do not permit singularities because of the violation of the uncertainty principle does not surprise me either - I'd expect that the beginning of time was so unique that perhaps a violation like this is to be expected.

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    Quote Originally Posted by Aethelwulf View Post
    Well, I've already established with another poster here that essentially we have dealt with BB appearing from a point is in fact what current theory says because ''we have attached it to have this significance''. Anything you may say is clearly not maintream - or how we traditionally describe the BB.
    We being who? I can vouch for a couple of university's Astronomy departments. But I guess that is nothing next your interpretation of what another person on an internet forum said.

    Sorry, no matter how you squirm it does not change the fact that the simplistic extrapolations you present here are not how the topic is taught or interpreted these days. Your position is no more valid than that of someone who seems a kitten grow and predicts that one day it will be larger than the planet.

  10. #40
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    I have moved this thread from Q&A to Astronomy.

    The explanation of the Q&A forum says the following:

    This section of the forum is for astronomy and space exploration questions with straightforward, generally accepted answers.

    Questions that are likely to lead to extended discussion about the correct answer, or that have no clearcut correct answer, should be posted in the forum most appropriate to the topic of the question. If a question does lead to such discussion, it may be split off or moved entirely to a more appropriate forum by a moderator. Since it's hard to tell how a discussion will go, posting such questions will generally be treated as a judgment matter and not a rule violation.

    Questions taking issue or raising concerns with the mainstream viewpoint should be posted in the ATM forum. Posting questions along these lines will generally be treated as a rule violation.
    For the moment, we'll see if this discussion can stay out of ATM
    Quote Originally Posted by Aethelwulf View Post
    And I really don't want to hear the ''this is not what mainstream says'' rubbish. I have read plenty texts on this subject and I can assure you, this is what maintream says.
    Aethelwulf,

    You really need to lose the attitude. To open a thread with a chip already installed on your shoulder is asking for trouble.
    At night the stars put on a show for free (Carole King)

    All moderation in purple - The rules

  11. #41
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    Penrose showed conclusively that general relativity
    predicts a singularity at time zero. But the concept
    of a singularity doesn't work in quantum mechanics.
    So either general relativity or quantum mechanics
    or both need to be modified in order to avoid giving
    conflicting predictions at and close to time zero.
    So the current best model is unable to make good
    predictions about conditions close to time zero.

    -- Jeff, in Minneapolis
    http://www.FreeMars.org/jeff/

    "I find astronomy very interesting, but I wouldn't if I thought we
    were just going to sit here and look." -- "Van Rijn"

    "The other planets? Well, they just happen to be there, but the
    point of rockets is to explore them!" -- Kai Yeves

  12. #42
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    Also, I've learned to take what Hawking says with a pinch of salt now. He's certainly not the beginning and end of discussion. He has already made fanticiful claims of a theory of everything, along with thinking that information is lost in black holes. He's been wrong and pretty much a science dictator all his life.

  13. #43
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    Quote Originally Posted by Jeff Root View Post
    Penrose showed conclusively that general relativity
    predicts a singularity at time zero. But the concept
    of a singularity doesn't work in quantum mechanics.
    So either general relativity or quantum mechanics
    or both need to be modified in order not to give
    conflicting predictions at and close to time zero.
    So the current best model is unable to make good
    predictions about conditions close to time zero.

    -- Jeff, in Minneapolis
    Yes true, the reason has to do with the Uncertainty Principle. You can't squeeze energy into a point without examining a violation in QM.

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    Quote Originally Posted by Swift View Post
    You really need to lose the attitude. To open a thread with a chip already installed on your shoulder is asking for trouble.[/COLOR]
    Sorry.

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    Quote Originally Posted by Jeff Root View Post
    But the concept
    of a singularity doesn't work in quantum mechanics.
    Well, it doesn't work in mathematics, either, and all these theories are expressed via mathematics. It's like dividing by zero. It doesn't work. It's undefined.

    Quote Originally Posted by Aethelwulf
    Also, I've learned to take what Hawking says with a pinch of salt now. He's certainly not the beginning and end of discussion.
    Good, and correct.

    Quote Originally Posted by Aethelwulf
    He has already made fanticiful claims of a theory of everything, along with thinking that information is lost in black holes. He's been wrong...
    Yes, on some things he has been wrong. Same as Einstein.

    Quote Originally Posted by Aethelwulf
    ...and pretty much a science dictator all his life.
    Well, that's taking it too far. He has over 200 publications, most of which are way over your head and mine, so how would we know? And of course, there are no science dictators, only peers.
    Everyone is entitled to his own opinion, but not his own facts.

  16. #46
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    Quote Originally Posted by Cougar View Post



    Well, that's taking it too far. He has over 200 publications, most of which are way over your head and mine, so how would we know? And of course, there are no science dictators, only peers.
    Maybe it was taking it too far. He does seem to move the finger more in his assertions nowadays mind you. Like dictating a theory of everything recently, to his conjecture that information is lost in a black hole... and he wouldn't listen to the physicists. I remember the so-called Susskind-Hawking debates on information. The physicists would get quite brutal sometimes.

    I am a big Susskind fan however.

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    Quote Originally Posted by Aethelwulf View Post
    He does seem to move the finger more in his assertions nowadays mind you. Like dictating a theory of everything recently...
    He may be a very knowledgeable physicist, but I never thought much of his books, especially his latest. He is not a great popularizer. Many others are much better at that. And I thought that latest book of his (and Mlodinow) was nothing new - he just took Guth's "free lunch" idea, which is decades old, and called it the Grand Design. I'm not saying it's wrong. I'm saying it's old. On the other hand, the book did show Stephen's sense of humor. He's a pretty funny guy, which is somewhat remarkable, given his illness.

    Quote Originally Posted by Aethelwulf View Post
    I am a big Susskind fan however.
    That may be a mistake. I'm often a big fan of whoever wrote the book I'm currently reading. I was very impressed with Alex Vilenkin's entry. But there's currently no way to test his idea, and it doesn't look like there's going to be for quite a long time, so my fandom has waned. Now I'm beginning to wonder why so many respected physicists, including Susskind, are speculating about ideas that are not currently testable and, in fact, may never be!
    Everyone is entitled to his own opinion, but not his own facts.

  18. #48
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    Quote Originally Posted by Cougar View Post
    He may be a very knowledgeable physicist, but I never thought much of his books, especially his latest. He is not a great popularizer. Many others are much better at that. And I thought that latest book of his (and Mlodinow) was nothing new - he just took Guth's "free lunch" idea, which is decades old, and called it the Grand Design. I'm not saying it's wrong. I'm saying it's old. On the other hand, the book did show Stephen's sense of humor. He's a pretty funny guy, which is somewhat remarkable, given his illness.



    That may be a mistake. I'm often a big fan of whoever wrote the book I'm currently reading. I was very impressed with Alex Vilenkin's entry. But there's currently no way to test his idea, and it doesn't look like there's going to be for quite a long time, so my fandom has waned. Now I'm beginning to wonder why so many respected physicists, including Susskind, are speculating about ideas that are not currently testable and, in fact, may never be!
    I think half the time he has been popularized is because of his ground-breaking work... more recently though, he has acted as a judge on scientific theories... most of this I bet was a publicity stunt... a certain Baron from my country made harsh remarks on this theory of everything... I will look and find details.

  19. #49
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    Quote Originally Posted by Cougar View Post
    Quote Originally Posted by Jeff Root View Post
    But the concept of a singularity doesn't work in
    quantum mechanics.
    Well, it doesn't work in mathematics, either, and all
    these theories are expressed via mathematics. It's
    like dividing by zero. It doesn't work. It's undefined.
    Mathematically it works just fine. General relativity
    predicts a singularity, and that by itself is no problem.

    The singularity that general relativity predicts is the
    beginning of time.

    The problem arises when you try to reconcile what GR
    predicts with what other branches of science predict.

    The example of a mathematical singularity that I keep
    presenting is the Earth's poles. When you are at the
    south pole, you no longer have a longitude, because
    the longitude is, as you say, undefined. But that does
    not cause any physical problem. It is possible to be
    at the south pole and have no longitude. The problem
    with time zero is not mathematical.

    -- Jeff, in Minneapolis
    http://www.FreeMars.org/jeff/

    "I find astronomy very interesting, but I wouldn't if I thought we
    were just going to sit here and look." -- "Van Rijn"

    "The other planets? Well, they just happen to be there, but the
    point of rockets is to explore them!" -- Kai Yeves

  20. #50
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    Quote Originally Posted by Aethelwulf View Post
    I think half the time he has been popularized is because of his ground-breaking work... more recently though, he has acted as a judge on scientific theories... most of this I bet was a publicity stunt... a certain Baron from my country made harsh remarks on this theory of everything... I will look and find details.
    Aethelwulf. After Einstein completed the General Theory in 1915, he embarked upon an attempt to unify all the forces of physics, having seen the early success of Maxwell in unifying electricity, magnetism and optics, under the one umbrella of electromagnetism. At the time he was widely regarded as a fool amongst his peers, who nevertheless respected his earlier work. Towards the end of his career, after he passed away,strides were made in unifying the strong and weak forces by,notably, Feynmann, Schwinger, and Tomonaga, and then, in the sixties, Weinberg, Glashow, and Salaam managed to produce the electroweak synthesis,predicting new particles (the Z 0) and it's neutral currents. Only then did many see that Einstein's instinct for picking the correct problem to work on was as unerring as it was in 1905......the big prize would be total unification of the strong, weak, electromagnetic and gravitational forces...the unified field theory for which he endured much disparate ridicule.
    In a similar vein, Hawking proved early on to be a math prodigy, and as such developed physical insight into the processes proximate to event horizons, melding developing mathematical theories into his physics and engaging some of the best minds in the world in his erudite excursions, which require training similar to his to read explicitly. He hardly has warranted being called a dictator, but merely does his job of asking questions....something scientists thrive on, and he often picks gentleman's bets of minor worth but immense fun and bragging rights...like a pair of friends fishing or playing golf for beers.
    So, we don't know it all. That's the game. Data banks slowly unravel the intersecting error ellipses of experiments and continue to refine our searches for new physics...like the Higgs @ the LHC, to pick new models. It's an exciting time to have an interest in physics. pete


    SEE:http://www-d0.fnal.gov/Run2Physics/higgs/
    Last edited by trinitree88; 2012-May-07 at 08:25 PM. Reason: link

  21. #51
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    Quote Originally Posted by Jeff Root View Post
    Mathematically it works just fine. General relativity
    predicts a singularity, and that by itself is no problem.

    The singularity that general relativity predicts is the
    beginning of time.

    The problem arises when you try to reconcile what GR
    predicts with what other branches of science predict.

    The example of a mathematical singularity that I keep
    presenting is the Earth's poles. When you are at the
    south pole, you no longer have a longitude, because
    the longitude is, as you say, undefined. But that does
    not cause any physical problem. It is possible to be
    at the south pole and have no longitude. The problem
    with time zero is not mathematical.

    -- Jeff, in Minneapolis
    This is true. Mathematically, from a relativistic viewpoint there are no troubles.. in fact, infinitely small points are very much welcome. It's only when you invoke QM that troubles begin... or so they say. Some of us, want to embrace these difficulties than rather seeing it as the ultimatum of all problems.

  22. #52
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    Quote Originally Posted by trinitree88 View Post
    Aethelwulf. After Einstein completed the General Theory in 1915, he embarked upon an attempt to unify all the forces of physics, having seen the early success of Maxwell in unifying electricity, magnetism and optics, under the one umbrella of electromagnetism. At the time he was widely regarded as a fool amongst his peers, who nevertheless respected his earlier work. Towards the end of his career, after he passed away,strides were made in unifying the strong and weak forces by,notably, Feynmann, Schwinger, and Tomonaga, and then, in the sixties, Weinberg, Glashow, and Salaam managed to produce the electroweak synthesis,predicting new particles (the Z 0) and it's neutral currents. Only then did many see that Einstein's instinct for picking the correct problem to work on was as unerring as it was in 1905......the big prize would be total unification of the strong, weak, electromagnetic and gravitational forces...the unified field theory for which he endured much disparate ridicule.
    In a similar vein, Hawking proved early on to be a math prodigy, and as such developed physical insight into the processes proximate to event horizons, melding developing mathematical theories into his physics and engaging some of the best minds in the world in his erudite excursions, which require training similar to his to read explicitly. He hardly has warranted being called a dictator, but merely does his job of asking questions....something scientists thrive on, and he often picks gentleman's bets of minor worth but immense fun and bragging rights...like a pair of friends fishing or playing golf for beers.
    So, we don't know it all. That's the game. Data banks slowly unravel the intersecting error ellipses of experiments and continue to refine our searches for new physics...like the Higgs @ the LHC, to pick new models. It's an exciting time to have an interest in physics. pete


    SEE:http://www-d0.fnal.gov/Run2Physics/higgs/
    I'm not saying we know it all. What I am saying is that we should not throw out these infinities as a breakdown in the theory. I believe also Dirac held a similar point. In regards to current day theory, we try and renormalize these theories... Dirac was largely unsupportive of this idea.

  23. #53
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    Quote Originally Posted by Aethelwulf View Post
    Yet, BB arose from such a state, we are led to believe. This is mainstream, again.
    Of mainstream scientific theory (GR, QCD/QED/QM) only one says there is a singularity, and that prediction can not be verified (surely not soon, and possibly not in principal). In that sense a singularity is much less a fact than something like time dilation.

    Besides theory there is a mainstream model of how the universe works: the standard cosmological model, of which the 'moment of creation' is not a part.

    So it is true only in a very limited sense that the mainstream says there is a singularity at the beginning of the BB (or for that matter, at the center of a black hole).

  24. #54
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    I actually don't care anymore, only that the mainstream model does predict a point. Where my trouble had laid, was with people who claimed the BB did not present a model far in the past that a curvature was infinite. Saying our model did not is highly against the mainstream.

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    Hello,

    The BB, as taught in my astrophysics class, starts AFTER the 10^-37 seconds, not at the beginning. As stated, since the laws of physics did not operate before that slight amount (but very important) time, there is no singularity in the BB. It is indeed overuse of that term that has caused confusion

  26. #56
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    Quote Originally Posted by Jeff Root View Post
    The example of a mathematical singularity that I keep
    presenting is the Earth's poles. When you are at the
    south pole, you no longer have a longitude, because
    the longitude is, as you say, undefined. But that does
    not cause any physical problem. It is possible to be
    at the south pole and have no longitude. The problem
    with time zero is not mathematical.
    Ha ha. The example I always recall is the equation for an orbiting spacecraft around a central mass. When the spacecraft impacts the central mass, that's a singularity in your equation. This does cause a physical problem.
    Everyone is entitled to his own opinion, but not his own facts.

  27. #57
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    Quote Originally Posted by Aethelwulf View Post
    I actually don't care anymore, only that the mainstream model does predict a point. Where my trouble had laid, was with people who claimed the BB did not present a model far in the past that a curvature was infinite. Saying our model did not is highly against the mainstream.
    BB theory is more than just GR. It does not predict a point because the model breaks down before then making any extrapolations invalid predictions. That is the mainstream view, taught in universities. If you are willing to make this sort of extrapolation why not go further? After it reaches a point the universe will expand again but with its spatial dimensions swapped. After all - plotting lines on a graph and then putting a straight line through them implies that. Got to be true.

  28. #58
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    Hello, Troka!

    Quote Originally Posted by Troka View Post
    The BB, as taught in my astrophysics class, starts
    AFTER the 10^-37 seconds, not at the beginning.
    The Big Bang was the beginning, if there was one, and
    whenever it may have been. The description of the Big
    Bang given in your class, on the other hand, may have
    begun with events after 10^-37 seconds, as there isn't
    anything known about any earlier time.

    (Actually, I would argue that nothing earlier than about
    one second is remotely close to being a sure thing. At
    that time nucleosynthesis began, and observations of
    isotopic abundances support calculations of the rates
    of change of density and temperature over the next
    couple of minutes.)

    Quote Originally Posted by Troka View Post
    As stated, since the laws of physics did not operate
    before that slight amount (but very important) time,
    there is no singularity in the BB.
    I think it is safe to say that the laws of physics operate
    at all times. But we don't necessarily know what those
    laws are. There is no reason to think that the laws we
    currently know did not operate at the very beginning.
    However, there is very good reason to think that the
    laws we know are not enough. Something beyond the
    known laws happened at the beginning. Something
    in addition to the currently-known laws.

    General relativity predicts a singularity at the beginning.
    Quantum mechanics says that prediction can't be right.
    So we don't know whether there was a singularity or not.
    We need to extend the laws of physics to find out.

    -- Jeff, in Minneapolis
    http://www.FreeMars.org/jeff/

    "I find astronomy very interesting, but I wouldn't if I thought we
    were just going to sit here and look." -- "Van Rijn"

    "The other planets? Well, they just happen to be there, but the
    point of rockets is to explore them!" -- Kai Yeves

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    Quote Originally Posted by Jeff Root View Post
    The Big Bang was the beginning
    Do you have a reference to support that, or are you just basing it on what the name sounds like it should describe. You have people who studied astrophysics/cosmology in the past saying that isn't the case. Now we have a current student saying that it isn't the case. Even good old Wikipedia says "The Big Bang theory is the prevailing cosmological model that explains the early development of the Universe.[1]"

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    Perhaps I should have said that the Big Bang was the
    beginning of everything that we know of: The observable
    Universe and at least some distance beyond what we can
    observe. It was the beginning of the cosmic expansion
    that we observe. Something may well have existed before
    that, and something may exist which did not participate in
    the Big Bang (other universes in the multiverse hypothesis).

    Saying that the Big Bang started after the Big Bang started
    doesn't work for me. Consistent descriptions of conditions
    start a miniscule fraction of a second after time zero. Time
    zero is defined by the Big Bang theory.


    Some definitions or descriptions of "Big Bang":

    Google.com

    1.The explosion of dense matter that, according to current
    cosmological theories, marked the origin of the universe


    http://wordnetweb.princeton.edu/perl/webwn?s=big%20bang

    (cosmology) the cosmic explosion that is hypothesized to
    have marked the origin of the universe


    en.wikipedia.org/wiki/Big_Bang

    The Big Bang was an event which led to the formation
    of the universe, according to the prevailing cosmological
    theory of the universe's early development (known as the
    Big Bang theory or Big Bang model).


    -- Jeff, in Minneapolis
    http://www.FreeMars.org/jeff/

    "I find astronomy very interesting, but I wouldn't if I thought we
    were just going to sit here and look." -- "Van Rijn"

    "The other planets? Well, they just happen to be there, but the
    point of rockets is to explore them!" -- Kai Yeves

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