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What do you think will be the fate of the universe?

  1. Aug 27, 2004 #1
    what do you think is the fate of the universe will be, i think that the hindus, buddhists, and mayans were right, the universe goes in cycles (since most of the stuff in it does) it makes sense to me, plus i find it hard to accept that the universe will just slowly decay forever, bit by bit
  2. jcsd
  3. Aug 27, 2004 #2
    That depends on what type of physics you believe in. First off, it hasn't been proven as of yet if the universe is a closed or open system. Second, some theories predict a multiverse, where new universes sprout from singularities of black holes (due to , I think, space tearing flop transitions). There are many theories out there. So, I have no idea what to believe in until the problem is solved.

    Paden Roder
  4. Aug 27, 2004 #3


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    I too would prefer the cyclic scenario. But I don't see how it's gonna happen.
  5. Aug 28, 2004 #4
    like PRodQuanta said, nothing is proven yet, there could be a discovery made tomorrow that will debunk the "long, cold death" theory, since nobody is sure its all just assumptions, i will go with the ancient mayans on this one
  6. Aug 28, 2004 #5
    I agree. I think that the universe is cyclic. Big Bangs are followed by Big Crunches. Once the cycle is complete, it repeats.

    Modern science does not place a high probability on this scenario. However, the jury is still out, and there are many problems with current theory such that the issue is by no means clear.
  7. Aug 28, 2004 #6


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    Think expansion. Every shred of evidence points that way.
  8. Aug 28, 2004 #7
    like i said, the universe just slowly expanding or stretching forever just doesnt sit right with me, it doesnt make sense to me, now im not no expert on this but i predict some rare events that will make the universe contract then it will expand again, contract, expand... so yeah

    actually you know what, the best answer right now would be insufficient data
  9. Aug 28, 2004 #8
    who else?...
  10. Aug 30, 2004 #9


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    Well, unlike your similar thread in General Philosophy - where I see you haven't answered my question - we can tackle this in a straight-forward way here ... what observational or experimental evidence did the 'hindus, buddhists, and mayans' have for their idea that the universe is cyclical? Now that you have at your disposal TB of high quality data from all manner of advanced instruments, what observations or experiments do you think are consistent with the idea that the universe is cyclical?

    As Chronos said, the current consensus view is that the universe will expand forever. Further, AFAIK, there are no 'cyclical universe' theories which can claim good consistency with the observational data.

    Of course, anyone can say that tomorrow there will be a new theory, or new observational results, but that's speculation, not science.
  11. Aug 30, 2004 #10
    Let me take a stab at this.

    It is true what you say about the current consensus among cosmologists. It is false to talk about the "current consensus" without this qualification.

    However, I do not think that any of the most prominent scientists say that there is zero doubt about the conclusion that you draw. Why not? Because the data is far from conclusive. For you to attempt to draw a definitive conclusion from the present data is not justified in my opinion, and apparently in the opinions of major cosmologists.

    The idea that the observational evidence supports your view is highly flawed. Although it might well be accurate, it is certainly not accurate in its present form.

    You place all of your apples in the same cart, current observatonal evidence of the poorly seen and poorly understood edges of the cosmos. The very names of dark matter and dark energy signify that they are poorly understood, and that they cannot survive in their present form.

    For you to attack religious ideas because they do not conform to your model of science is unfair, in my opinion. Your model sees only a small portion of the universe, yet you seem to be contending that your tiny portion of view is overwhelming superior to what you believe is a lesser view of another model of nature. I consider that this is completely unjustified.

    The main reason, I believe, that modern science believes that the space is infinite is the extremely narrow-minded view of Euclidan geometry that causes it to be seen as such. Surely, you recognize the incredible limitations of science. How can you be so sure that your current conception of the nature of the universe is so superior?

    The life of animals is cyclic. Your life is cyclic. You evolve through your life in the same manner as your parents. If you have children, they will follow the same cycle as you. In the same manner, the life of species is cyclic. Species evolve into other species in the same manner as each life evolves into another life.

    The pattern of evolution that we see around us follows a cycle. There is tremendous evidence of this. Look at the evidence. Do you not see the tremendous evidence? Look at your own life and that of your species.

    There is only one nature. Nature seems to follow the same cycle of evolution. Currently, scientists are lost. They are stretching into ideas such as dark this and dark that in order to justify continuing to pretend that they understand what is "really" going on.

    There is only one nature. It is not far-fetched to assume that everyting follows the same cycle of evolution we recognize around us.

    This, then, is observatonal evidence. And there is lots of it. The Buddhists, etc. have their share of observational evidence. For you to pretend that only your narrow range of evidence is valid in this argument is self-serving, in my opinion.

    I think that you should not point to the superiority of your selected evidence and pretend that it is the only valid evidence, at the same time ignoring how flawed your evidence clearly is. Perhaps this is why no one, I believe, believes with 100% absolute certainty that the universe MUST be infinite.
    Last edited: Aug 30, 2004
  12. Aug 30, 2004 #11
    Let me try again.

    We look at life on earth, and it is cyclic. The life of each individual and the life of each species is cyclic. Do you dispute this?

    The Hindus, etc. observe relationships in nature that they view as cyclic.

    Based on their observational data, many people consider that nature is cyclic. It is reasonable to assume that there is one nature, and that nature is cyclic.

    For you to make the claim about "observational evidence" as you do, you must consider that there are many forms of nature. Here on earth perhaps it is cyclic, but elsewhere in the universe it need not be. Even though we don't understand the universe as a whole, you would ignore what we do know for what we do not.

    You claim that the observational evidence does not support the idea that the universe is cyclic. Does the evidence do this easily, and without dissent?

    What is this observational evidence you so rely on? Based on your observational evidence, we must "recognize" that 75% of the known universe is of a nature that we do not understand, which we call dark blah. Another 21% of the universe is of a different nature that we do not understand, which we call dark blah 2. Based on what we think that we understand of the universe, 4%, and what we know that we do not really understand, 96%, we can create a model of the universe wherein space is infinite and non-cyclic.

    Feel free to believe that space is infinite and non-cyclic, based on a model of nature wherein 96% of our "observational evidence" is dark, and clearly not understood well. Feel free to ignore all of the observational evidence that we do understand well, which other people use as their basis for considering that the universe is cyclic.

    I fail to understand how you can consider the observational evidence that you recognize to be so overwhelming that other theories, which are based on better understood evidence, are so clearly faulty.
  13. Aug 30, 2004 #12


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    Thank you for your considered response Prometheus. Let's examine this question within the context of this section of PF (General Astronomy & Cosmology). First, we note that discussions in the science sections of PF are to be within the scope of the mainstream science of that section, with Theory Development for discussions - in accord with scientific principles - on more speculative ideas. Then we note that there is a vibrant section of PF on the philosophy of science (etc), and several threads in which your comments would be good contributions to the ongoing discussions (e.g. there's a good one on 'can physics explain everything' (or some such title).

    Next let's clear up a few things about science in general, with examples of how science works wrt cosmology.
    Almost. In science there can *never* be zero doubt; someone could make an observation tomorrow which was inconsistent with the best theories of the day, and those theories would need extending/replacing/modifying. Of course a corollary is that *nothing* in science is conclusive, not even QED (quantum mechanics extended to incorporate Special Relativity), which has been shown to match observations to ~17 decimal places, is 'conclusive' :surprise:
    Sure! :eek: That's what science is - a good theory is internally consistent; consistent with other, well-established theories; and above all else consistent with all observational and experimental results within its domain of applicability. If the observational constraints are weak (say, only 1 OOM, or 1 decimal place), then we all look forward to the time when stronger constraints can be placed on theories. Wrt dark matter and dark energy, you and I may not like the 'mysterious' nature of these beasts, but we can say with some confidence that the concepts are consistent with observational data.
    With respect, if we are discussing science, the 'unfairness' is the other way round - attempts to introduce explanations which are not falsifiable by observations and experiments - even in principle - makes such explanations non-scientific (and so they have no place in GA&C).
    The main reason that the concordance model in cosmology has widespread (but not universal) acceptance is that it is consistent with the best observations and experiments to date. Science makes no claim about superiority or otherwise of its theories, only that they are consistent (you get the idea).

    For the rest of your post (except the last para), these ideas are interesting ... now if you can turn them into a set of hypotheses, we can go test them and see if they are consistent; until then, they are merely speculation and have no place in science.
    Good, let's see what evidence the Buddhists etc have; we'll then match against the best observations and experiments and see for ourselves their level of consistency.

    If you think that the current observational data - primordial abundances of nuclides, cosmic microwave background radiation (inc acoustic spectrum and polarisation data), large scale structure (e.g. results from 2dF, SDSS), gravitational lensing, virial theorem applied to galaxy clusters, inter-galactic gas equilibrium determined from X-ray observations, expansion rate (both Hubble and accelerating expansion, from distant supernovae observations), etc - is 'flawed', then let's see you present those flaws for us all to read!
  14. Aug 30, 2004 #13
    I think what Prometheus is trying to say about life being a cycle, is very different to how the universe itself would cycle. Life doesn’t die then come back to life, that’s not the definition of cycles for life. On the other hand if the universe were to contract and then be recreated, the term cycle is used because it does end and begin a new cycle.

    The difference is the mechanism by which both take place, life produces progeny, but the cyclic universe would recreate itself…
  15. Aug 30, 2004 #14
    Why? Each cycle of life is born and it dies, and it gives birth to the next cycle. If the current cycle of life of the universe were to give rise to the next cycle, it would not be dying and coming back to life. It would be dying and giving rise to a new and somewhat different cycle in the life of the universe.

    I don't understand your point. Can you rephrase it to make it clearer?
  16. Aug 30, 2004 #15
    Excellent!! I await the results of your detailed investigation. You are offering to seek out and examine the evidence that they contend is visible, are you not?

    Excuse me, but may I ask you a question? Are you personally completely familiar with all of the observational evidence that you have discussed? In other words, have you personally observed all of this evidence yourself and contributed to its evaluation, or are you relying on the interpretation of others?

    I am asking because I wonder if I were to present evidence, would you be examining it with the thoroughness that you have examined all observational evidence that is currently available, or would you be examining it from the perspective of someone who has only secondhand understanding of all currently available observational evidence and its interpretation.
  17. Aug 30, 2004 #16


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    As I see is not uncommon in everyday speech these days, 'my bad'. The way science is done is someone proposes an idea, and shows that it's consistent with observations. In this case, you (or maybe Gold Barz) proposed that Buddhists (etc) believe the universe is cyclical, so the onus is on you (or Gold Barz, or Buddhists, etc) to provide the evidence ... but first, you will need to state clearly what the 'universe is cyclical' idea actually is, preferably by providing some testable, quantatitive predictions.
    Try me; we can read the peer-reviewed papers of those who did the observations together; we can dig out the raw data (e.g. from the Hubble Space Telescope) and perform our own analyses - together; and so on. Further, you don't have to take my word for any of it ... you have access to pretty much the whole multi-TB of data from all those observations, and you are entirely free to perform your own analyses of that data, so confirming the conclusions you can read in publicly available, peer-reviewed papers.

    After all, if this were not the case, it wouldn't be science, now would it? :wink:
    Don't be shy now!
  18. Aug 30, 2004 #17
    You see we are talking about the mechanism by which life gives birth to another cycle. There's a theory where by black holes give birth to baby universes, however this is not the cyclic model, and recently it has been stated by Hawking that what's inside a black hole remains firmly within our own universe. The mechanism is through black holes, whereas the mechanism of the cyclic universe is through a total re-collapse and does not resemble the same mechanism of reproduction as life.

    I’m not sure why you associate the mechanism of creating new life to that of the cyclic model?
  19. Aug 30, 2004 #18
    So, in other words, if I were to present evidence, you would be subjecting it to that part of the secondhand evidence that you have gathered while not considering the evidence that I propose. You would only look at peer-reviewed papers, so that not only is your information second-hand, but it is limited in scope, as though only these papers are worth your time to base your second-hand opinion on.

    My point is that I would like to discuss the concept of a cyclic universe with you. However, you would force me to follow your rules for what is acceptable evidence, and by your own admission you only allow certain types of evidence. Furthermore, you gain your evidence in a secondhand manner, yet you would consider your opinion conclusive in determining the relative merit of my theory, even though you did not contribute your opinion to determining the relative merit of the theories that you hold up as "consensus".

    I do not feel that you would offer a fair and impartial forum for the evidence that I consider important.

    If I were to present a theory that I contend fits the observed evidence, and it seems that you have no more firsthand experience with the observed evidence than I, you would say that I must find a peer-reviewed paper that expressly supports my idea. If not, so what? I would not mind if you state that my theory is therefore not accepted as "consensus", which would be obvious, but I get the feeling that you would apply a far stricter standard even to allow me to contend that it is a scientific theory at all.

    There are many cosmologists who believe that the universe is cyclic. Some of them have been published in peer reviewed journals. For example, I read articles by Paul Steinhardt and Neil Turok that clearly promote this idea. You might consider them wrong, and you might talk about "consensus", but how can you evaluate this with such surety, as you claim to base your ideas on those ideas that you happened to read in the peer-reviewed journals that you happen to read?
  20. Aug 30, 2004 #19
    I am not sure why you reject it.

    Each person is born, increases, declines, dies, and contains the seed that perpetuates the species.

    Each cycle of the universe is born, it expands, it contracts, and it dies, yet it contains the seed that perpetuates the cycle of the life of the universe.

    To me, these do resemble each other. What about this comparison that I have listed do you dispute?
  21. Aug 30, 2004 #20
    I don't know what will happen. But I can tell you it will be suprizing.
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