Is there only one big bang.

Discussion in 'Astronomy, Exobiology, & Cosmology' started by Lord Vasago, Sep 10, 2009.

  1. prometheus viva voce! Registered Senior Member

    String theory is far more than a hypothesis. It has rigorous mathematical structure and many predictions, some that agree with previous theories and some that cannot be tested yet because the experimental technology is not there. Calling it a hypothesis demeans it. A hypothesis is something that is an idea that has no structure or support, whether it is mathematical or experimental.
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  3. AlphaNumeric Fully ionized Registered Senior Member

    If you can manage to post more than twice between banning/suspensions I'm happy to discuss things with you Kaneda, provided you can play by the ground rules of providing sources for claims so we don't descend into "My interpretation of what someone else says about a theory I'm not familiar with...." shenanigans .

    Many times I've told you I've got nothing to hide, such as offering to discuss my work with you. The shortfall is at your end.

    I think we need to distinguish between how the word 'theory' is used in layman discussions and how its rigorously defined in non-layman discussions.

    For instance, such things as 'string theory' and 'Newton's laws' are misnomers and you won't find any scientist claiming otherwise. It's been my experience that every single person who has made the "Well its a theory, not a law, like thermodynamics!" criticism doesn't understand quite what those terms mean or that the superficial names for things does not always reflect what is 'under the hood'.

    For instance, there's a general area of theoretical physics known as 'gauge theories'. It's a phrase I hear multiple times a day but I also know that the general concept of 'a gauge theory' is not something which has been hypothesised, tested and verified to a good accuracy, it's the name given for models constructed using the concept of gauge invariance, 'theory' is just a colloquialism for 'mathematical framework which in some cases is part of a highly predictive and accurate model of some set of phenomena'. Obviously saying 'theory' makes conversations flow a little.

    I don't think you can go about criticising the everyday naming of things, as if what people find easier or quicker to say is somehow a sign that the underlying methodology or concepts are wrong. Ask any physicist if string theory is literally a theory in the strictest sense and you'll get an explaination why it isn't but it has the possibility that it might become one. Such things as unspoken but widely known things in the physics community and you seem to be criticising them/us for not always making particular nuances of terminology clear to people not in the field themselves. Terminology is there to make people 'in the know' communicate faster and easier and sometimes terminology is slap dash or odd to people who don't know the details. I'm sure anyone whose a good computer programmer will know loads of silly named things in the world of computer tech speak. It's no different in physics and you can't blame us for not taking the time to explain the specifics of everything everytime we speak.
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  5. Lord Vasago bcd Registered Senior Member

    this is getting ridiculous. The fact of me being in a club has nothing to do with the question i asked.
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  7. quantum_wave Contemplating the "as yet" unknown Valued Senior Member

    My apologies.
  8. Lord Vasago bcd Registered Senior Member

    Why should a question be measurable ???? 80% of the worlds population is religious (me belonging to the 20%). How many questions are posed daily that in no way can be measured yet influence the whole world?
  9. kurros Registered Senior Member

    While I am not religious, I can accept that religious questions help people accept their place in the universe, society, whatever (hopefully), and I'm sure those so inclined would argue many other benefits. Science doesn't really concern itself with that kind of thing so if it is not observable scientists don't care about it. In other words the psychological impact a theory has is irrelevant, only its physical content matters.
  10. antaran_1979 Registered Senior Member

    i think that multiple big bangs resulting in a "foam" of universes is not really that far fetched to imagine. however as already stated so far there is no way of eighter confirming od denying this.

    as fo the arealy post of describing two points at the oposing sides of the universe...well i find this hard to comprahend. the universe it self is not "geographical" in the the conventional meaning of the word. there are no two oposite sides in space alone, as if this is where the universe's boundry is now and beyond it there is nothing. there is also no way to "overtake" this expanding universe and observe it from the outside. most bluntly said, the universe is not an expanding shere. not in the clasical geometrical terms anyway.

    when we talk about the oposite sides of the universe, we must contemplate on its very nature. the universe is not just space but space-time. so the 2 oposite sides of our universe are not placed in oposition to the geographical locations, but rather in the temporal. the 2 oposite sides are "now" and the "beggining". this leads to some counter intuitive conclusions. because of the space-time "size" or "dimensions" of our unverse, when we say that the inverse has expanded i.e. 15 bilion years and it's now 15bilion ly in size or across it does not mean that we are the center of sphere that is 15bilion ly in radius. actually if you sudenly move magicaly 15bilion ly in one direction at what should be the universe's edge, you'd still be in the center of 15bilion ly universe and no nearer it's boundry. that is because we are living on it's boundry. that boundry is time-bound and that time is now. if the universe is indeed a sphere then it is a sphere where the radius and the diameter are one and the same.

    so there is no edge, just like in the black hole. the boundry betwean the event horison and the normal space is not some mesurable distance in space no mater how small, but rather it is in time. a slong as one utilises conventional time-space means explanation of the true nature and laws behind the event horison or what lies beyond is very difficult if possible at all. there are people that work on this and there are many "theories" but as far as i am informed, there is no prevelanet thought at the time beaing.
  11. Michael 歌舞伎 Valued Senior Member

    If I were in a "rocket" and could travel 15 billion times faster than the speed of light and traveled from earth in a line, just straight up into the air - would I end up back at Earth? Which side of Earth?

    Second question. IF time stopped for everything but what I touched. And I traveled in a straight line into space - then what?
  12. antaran_1979 Registered Senior Member

    the answer to the both questions depends on wether the universe is "closed" or "opened". in a gravitationaly closed universe (i.e. a 4D sphere) you should at some point return at the place you started from, but i'm not sure if the side from which you will return can be determined. my intuition tells me it ould be from the oposite side, but conclusions and implications in general relativity are often couner-intuitive.

    the second question is kind of contradictory. if time stoped, then the universe would end. travel within a universe that has ended would only be a matter of some kind of time travel, what and how can this be explained or perormed (if possible at all) is beyond me.
  13. decons scrambled egg Registered Senior Member

  14. fedr808 1100101 Valued Senior Member

    Well the big bang originated from a singularity that exploded. A point in space of no volume and infinite density.

    and since density is a function of mass per unit volume. mass over volume equals density.

    And since the volume is zero, and the density is infinity,
    infinity= mass/0

    this is where we hit the barrier of quantum physics and normal physics and math.

    In normal math the mass would equal zero, because 0 times infinity equals infinity.

    But in quantum physics mass would equal infinity because if you tried to replace mass with zero it would render the statement untrue.

    But that does not mean that it any black hole contains infinite amounts of matter, because that means that every single of the infinite black holes contains every matter int he universe at the same time.

    But what it does mean is that the singularity that started it all, the big bang, contained infinite amounts of matter inside.

    Disclaimer: At this point Im passing into my own opinions and thoughts.

    now the interesting thing is the fact that a vacum like in space or an area with zero atoms, isnt a true vacum, because it contains some sort of matter or force, maybe anti matter or dark matter.

    That has to be the reason why every single singularity does not just spontaneously explode like the big bang did. So that means that the environment that the singularity came from had to come from nothing, literally there could not have been anything to exert any sort of force on the singularity.
  15. Pasta Registered Senior Member

    I read an article in the journal Science a few years ago, I wish I could link it because it touched on this subject and was very interesting.

    In a nutshell what the author said was the Big Bang itself was a natural phenomena, and like all natural phenomena was repeatable when the conditions are right. If the cosmos is infinite in time and space (and perhaps dimensions), then it's likely that there's been and will be infinite other universes born from other big bangs.

    An interesting question they touched on was with all the infinite universes, is it possible for a perfectly identical universe be born as the one we're in that followed the same time line ? and if history was repeated in that universe and identical copies of us were recreated with the same life historys, would they just be copies of us ? or actually be us again ?
  16. Fraggle Rocker Staff Member

    This is the multiple-big-bang model which I have posted on this board and also on the "Nothingness of Nothing" thread in Comparative Religion. It relies on the loophole in the Second Law of Thermodynamics, which says that entropy "tends to increase" but does not increase monotonically. Local reversals are possible both spatially and temporally, and the Big Bang is, in essence, a rather large local reversal of entropy.
    Nonetheless these reversals would, presumably, be very rare. It's quite possible that even in a spatially and temporally infinite universe, there are/have been/will be only a finite number of Big Bangs. Science hates singularities so that number may not be one, but it could be thirty-seven.
    I don't see any convincing reason to assume that, if this model is correct, it results in an infinite number of individual universes. As I said, there might only be three dozen total. In that case the probability of two of them being identical is too small to entertain.
    Depends on what you mean by "us." This is getting off into semantics! We're all just big collections of bosons. What do you call two of them that happen to be identical? They're not the same bosons, so no matter how exactly identical they appear, they're not the same table or chair or rock--or human.
  17. tostig Registered Senior Member

    A while back on the radio (I don't know when) a news report stated that all evidence so far indicates an ever-expanding universe. It went on to say the expansion is slowing but will never stop or reverse and the end state will be no (zero) thermodynamic activity.
  18. Pasta Registered Senior Member

    Sorry, I may have not accurately stated what I meant. I meant big bang's occuring not just from quantum fluctuations within our own universe, but the entire cosmos (outside our known universe as well).
    If the cosmos is infinite in all dimensions (and time), I can understand an infinite number of big bangs occuring throughout eternity. But I don't understand what you meant by an upper limit of perhaps a few dozen big bangs ? or were you just referring to big bangs originating from our universe, limited by it's entropy ?
  19. Forceman May the force be with you Registered Senior Member

    There was a showing on the Universe talking about the future of our universe, in which the net geometrical curvature of our universe will lead to a pulling effect of each galaxy on each other (a minor scale example being the possible future collision of Andromeda and our Milky Way) causing what is known as a Big Crunch. If there truly is a multiverse (consisting of anti-universes and "normal" universes), then the BIg Bang/Big Crunch mechanism is occuring and universes are being birthed and destroyed. That's why theoretical physicists and futurists say if there is a human civilization millions of years, from now, we would need to use a quantum gateway into another universe (ideally younger than ours).
  20. marcmait Registered Member

    Statistically speaking, there must be billions of "BIG BANGS" going on all the time. I think the symetry we see in our present universe today proves this; this, and the fact that the acceleration of the expansion of our universe also hold proof for this. But I'm not the one who brought up the topic of vacuum energy... so the background radation must undoubtably come from this source as well. If this is true then I find it hard to put a time stamp on the age of our universe and much less define its boundaries. Hey, I could be wrong... But I'm not afraid to admit it.

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