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Infinite Space

  1. Oct 9, 2014 #1
    It would seem to me that we exist in an infinitely large space.
    That a big bang could not encompass all matter because all space extends infinitely.
    That with infinite space there is infinite possibilities for things to happen, such as for matter to exist.
    That space can exist and is infinite, and that matter is allowed to exist within space, because 0≠0, because nothing is something.
    That a big bang is a measurable explosion, and one that can be considered large or small, just as we see small and large explosions on our planet. Not saying that big bangs may occur in different sizes, more like the size of the explosion is in the eye of the beholder.
    That the contents of a big bangs explosion cannot be the entirety of a universe, that the universe is singular and infinite, that there is no such use for multiverse theory.

    Would anybody like to comment anything? This is just my amateur ideas.
     
  2. jcsd
  3. Oct 9, 2014 #2

    Bandersnatch

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    Better known as misconceptions. Don't worry, we've all been there.

    Big bang wasn't a localised explosion. If the universe is infinite(as it seems to be according to current best measurements), then BB occured everywhere in its infinite extent at once.

    What have you read so far about BB? We can link you to some good introductory materials if you're interested.
    If you haven't read much, then a good start would be to read the cosmology FAQ here on PF, or make a forum search.
     
  4. Oct 9, 2014 #3
    I haven't read all that much but I should because I would like to come to grip this information. Most of what I have read I have not agreed with or did not understand. I'll go have a look around the forum and surely would appreciate any links.
    Thanks, David
     
  5. Oct 9, 2014 #4

    Bandersnatch

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    Here's a few:

    http://www.mso.anu.edu.au/~charley/papers/LineweaverDavisSciAm.pdf
    http://www.phinds.com/balloonanalogy/
    The above cover what is known as "balloon analogy" of the expanding universe.
    The first is a public outreach article by two well-regarded scientists in the field, and should cover most of the basics. The approach is to tackle common misconceptions that arise from the analogy. It's extremely well written and informative.
    The second is by one of PF members, and should be of help if you're not too familiar with what the balloon analogy is at all.

    http://www.astro.ucla.edu/~wright/cosmolog.htm
    This is Ned Wright's cosmology tutorial. It's very in-depth, and as such requires (quite) a bit more of time and effort investment to get through. Start with either "Enter the tutorial" or "Frequently asked questions".

    http://www.einstein-online.info/spotlights/big_bangs
    This blog post delineates the two different ways BB is used in literature. It should help clear many past and future misunderstandings that could otherwise arise.

    https://www.physicsforums.com/threads/universe-geometry-article.694499/#post-4406311
    The above post developed by member Mordred and others in a concise manner covers Universe geometry - an integral part of current cosmology.

    These should cover most bases, inlcuding what we think about the Universe, and how we got there.


    edit: this one's great as well: http://preposterousuniverse.com/writings/cosmologyprimer/index.html [Broken]
    It's by one of the top scientists in the field, but aimed at laymen.

    By the way, it's a lot of material, but a lot of it overlaps, so any single one of them should get you up to speed. Some better than others, but still.
     
    Last edited by a moderator: May 7, 2017
  6. Oct 9, 2014 #5

    Mark44

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    The "reasoning" here is illogical; in particular your statement that 0≠0, and that nothing is something.
     
  7. Oct 9, 2014 #6

    phinds

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    DHooley, I reported you post as a personal theory gone wrong but I am very pleased that the mods did not delete it. I was overly harsh in my quick analysis and I'm glad to see we are giving you help instead of following my original idea of deleting the post (personal theories are not allowed here). Fortunately most folks here are not as mean as I am o:)

    The balloon analogy (and an analysis of its pros and cons) that Bandersnatch pointed you to is a work that I did in conjunction with several folks here on this forum and I think it's an excellent place for you to start. It also has links at the bottom to a couple of the other links Bandersnatch gave you, so I agree w/ his list.

    The cosmology FAQ on this forum is also excellent, as I see he also pointed out.

    Hm ... basically I seem to be just saying that Bandersnatch is a wonderful fellow and has pointed you in the right direction. :p
     
  8. Oct 10, 2014 #7
    Since the other problems with your ideas has had good responses, let me respond to these remaining problems.

    There are problems of both statistics and physics as soon as you go to the extremes of singular objects and inifinite spaces.

    - We don't have a probability theory that works for infinite spaces, which is the simplest take on the LCDM cosmology - there is a local universe, but the multiverse spacetime could well be infinite. So we can't say if there are "infinite possibilities". (Of what?)

    At the same time we do know that we have laws (such as quantum mechanics and thermodynamics) that extend to all of such a universe. And teh simplest take here is that the physics of the standard particle model extend to other local universes. That speaks against "unconstrained physics". (Say, of "infinite possibilities" applied too broadly.)

    - We don't have a probability theory that works for exceptions outside the observed distribution, which is the simplest take on an idea of "nothing" - everything we see consists of somethings, and the inflationary universe could well be eternal both backwards and forwards. So we can't say if there are "nothings". (Of what?)

    At the same time we know that we have laws, yadda, yadda. That speaks against "non-existence physics".

    Both of these idea constitute extraordinary claims without extraordinary or even ordinary evidence.

    FWIW, I think physicists like Tegmark ponders "infinite possibilities" and cosmologists like Krauss ponders systems that are more "nothing" than what we know of. But it is rather fringe, I think. Not necessarily bad fringe this time, but not very productive so far either. Probabilities of "infinities" do better (and is what is used in quantum mechanics in a way), so maybe there will come something out of it eventually.
     
  9. Oct 12, 2014 #8
    Here's my philosophy. Infinite space is a math abstraction. Hystory of Physics teaches us infinities in reality don't exist. BBT says our universe has the beginning in time. Quite likely it has its end too. Thus, I'm quite sure we live in a finite (but VERY large universe). According to current observations our universe is getting bigger and bigger, faster and faster. Is the "big rip" the most possible death scenario or something else is on the table ?
     
    Last edited: Oct 12, 2014
  10. Oct 12, 2014 #9
    No it does not.
    It is a common misconception
    It tells us they we don't have a theory which works for t near 0.
     
  11. Oct 12, 2014 #10
    Whatever. Most likely time loses it's usual meaning near that point anyway
     
  12. Oct 12, 2014 #11

    phinds

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    Yes, and this forum is not about philosophy, it is about science. There is no evidence that the universe is finite or infinite. The best evidence right now seems to be trending towards an infinite universe but it is not conclusive. You should know that your "logic" ("Thus, I'm quite sure ... ") has no standing in science. You need empirical evidence and a solid theory that supports (and preferably predicts) that evidence.
     
  13. Oct 12, 2014 #12
    Those are both misconceptions over a decade old. As far as I understand this, dark energy put a stop to the first idea, while inflation did the same to the second, in the sense that you need to insert new physics in order to reinsert them. (More precisely, the notion that time looses its meaning somewhere in the big bang phase was notional and becomes difficult.)

    1. LCDM shows that the vacuum energy density of our universe is under control. Therefore there can be no vacuum energy "runaway" as was envisioned in the big rip, unless you insert new physics.

    "The hypothesis relies crucially on the type of dark energy in the universe. The key value is the equation of state parameter w, the ratio between the dark energy pressure and its energy density. At w < −1, the universe will eventually be pulled apart. Such energy is called phantom energy, an extreme form of quintessence."

    [ http://en.wikipedia.org/wiki/Big_Rip ]

    In LCDM w = −1, which is also what is observed within experimental error. [Planck data release.]

    2. Unless you insert new physics, you can't derive a singularity from our semiclassical physics of the current cosmology. According to inflation, the time where you expected it is moved indefinitely back, in the sense that the era is an exponential expansion. So the question of what happens is open, but so far time doesn't lose its meaning:

    universehistoryreliability2.png

    [ http://profmattstrassler.com/2014/03/26/which-parts-of-the-big-bang-theory-are-reliable/ ]
     
  14. Oct 12, 2014 #13
    ...Assuming 'without any new physics' or modifications(we just don't know yet). Our universe 'might' end up in big freeze --- maximum state of entropy-- coldest it can possibly be.

    Things get weird in a cold state. If phase transitions occur at the coldest temperatures imaginable, where quantum mechanics reigns, subtle fluctuations can dramatically transform a material. Materials became superconductive, super-fluid, ferromagnetic, and so on. Will it take an effect on the fate of the universe? I have no idea..
     
    Last edited by a moderator: Oct 15, 2014
  15. Oct 12, 2014 #14
    I would say that in Planck epoch (before t ≈ 10-43 s), usual conception of time definitely loses its' meaning. Some say that epoch is in state of "spacetime foam". Also, about details of steps of so called inflatory epoch we know practically nothing. All this is highly speculative.

    regards
     
    Last edited: Oct 12, 2014
  16. Oct 15, 2014 #15
    That was the point, it is highly speculative to say that the "usual conception of time definitely loses its' meaning". Look at the figure, we can't say anything like that with any experimental support whatsoever.

    Inflation mean a "Planck epoch" must be rejected - the HBB never got that energetic - and you have to resurrect the putative idea earlier as per my earlier comment. In my opinion that idea doesn't seem very robust, so it wouldn't place very high on my ideas of what physics is needed to predict earlier times.
     
  17. Oct 15, 2014 #16

    Chronos

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    Much depends on whether time and space are emergent properties of our universe, or an absolute background in which our universe is embedded. One could argue [as have many] that our universe is temporally and spatially bounded. This, in fact, is an essential element of BB theory and strongly supported by observational evidence. It does not, however, rule out the possibility our universe is merely one among an essentially infinite number of other universes with an infinite variety of ages, sizes and rules. Such other universes are generally believed to lay beyond the horizon of our universe rendering them unable to influence events in our universe [i.e., causally disconnected]. Some theorists have suggested this may not always be true, motivating searches for evidence [which has not been found]. There is an essentially infinite number of ways to describe things that lack observational support, but, I leave that choice to the reader. Our current most popular theories are surely incomplete and suffer unknown caveats, but, do not suffer lack of observational support.
     
  18. Oct 18, 2014 #17

    Nugatory

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    I've removed some extraneous personal theory stuff and a few stray insults from this thread.

    Everybody, if you see stuff going on that's contrary to the letter or spirit of the PhysicsForums rules, please use the "report" button to bring it to the attention of the mentors.
     
    Last edited: Oct 18, 2014
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