Against physical laws. E.g. reversals of entropy . . . Doesn't that just mean that even if the energy is a homogeneous mush, as the universe expands it can become an even thinner homogeneous mush? But is it useful beyond a certain point?
Personally I think our use of the word "Universe" to describe "that thing which occured as a result of the Big Bang that current data seems to support fairly well" is somewhat of a misnomer. At one point, the Milky Way Galaxy was considered "The Universe" until at some point (not sure when) it was discovered that our home galaxy is simply one of many such structures. Likewise it is possible, I suppose, that there are other "universes" as in other Big Bangs "somewhere else" - another concept eventually bound for the intellectual trash can - that may again redefine what "the universe" really is/means. It sounds hectic and mathematically foreboding, but actually it is just a matter of nomenclature. The existence of "others" would force us to come up with a name for the "local" collection of galaxies, of "all that is" - all that is known to be governed by the laws of Physics as we experience and measure them on planet Earth. The word "universe" would then be applied more appropriately to "everything that could possibly ever be, anywhere, anytime." It's sort of a cycle that has repeated as our ability to understand our surroundings has expanded. The dominating philosophy in our civilization from the time of Christ to perhaps 1000 ce was something like "the earth is a sort of planar island floating in some etherial universe governed by God (or gods)" - call it the Young, Flat Earth Theory Pretty ridiculous theory, but your average Joe Blacksmith from Whereverville really had no need for a more accurate conception of it - he needed his professional skill set, his ability to manage his resources and protect his home and family from outside forces that might threaten it. (of course a handful of intellectuals have conceived of much more accurate models throughout the course of human history - these were generally useless to everyday people more worried about something like the Black Plague, or invading people from other lands...) At some point in there we had a Solar Neighborhood model - the sun and the planets and a bunch of points of light of unknown nature. This was succeeded by the Bunch of Stars Like Our Own model, and that eventually led to the proposal that perhaps we were a part of some larger structure - this of course turned out to be a galaxy... The point is we have always seen to the very edge of technology and reason and declared, "THIS IS IT, WE NOW UNDERSTAND THE UNIVERSE!" And at each step we were wrong. I am simply proposing that we are (probably) still wrong. It will just take Physics another couple of decades to push the edge of our "universe" further out. We may never conceive of "all that is."
Ok, now we're splititng hairsPlease Register or Log in to view the hidden image! We'll say "really big". I think that using the furthest galaxies might be a bad idea, considering galaxy formation took maybe a billion years or so. Essentially, you're choosing an arbitrary event, i.e. first galaxy formation, to define what is the size of the universe. The natural event to define the size of the universe is the big bang. Hmm. I am by no means an expert in the second law, but I know that one can phrase it in terms of a statistical argument. I have seen calculation estimating the time between second law violations to be on the order of 10^68 seconds, or something ridiculously long like that. The point is, if the universe is infinite, then the second law is violated somewhere! I am about to become in danger of talking out of my assPlease Register or Log in to view the hidden image! Could you clarify this a bit? Sorry if I'm slow.
Ok. Zephyr has made me realize that I may be slightly mistaken, when he said his bit about physical laws. I said earlier that the universe should be homogeneous and everywhere outside of what we see should look surprisingly similar. There is another possibility. Namely, if we suppose that there is some grand unified theory immediately after the big bang, then there are no guarantees that the rest of the universe looks like our little patch. Explain this. Ok. What you should know is that it seems likely that the matter in our universe obeyed the symmetries generated by the group SO(10). What does this mean? In phyiscs, forces are manifestations of symmetries between partcles. A grand unified theory takes all of the forces and all of the matter, and embeds them in one description. So, for example, it is possible that immediately after the big bang, there were two forces---the grand unified force, described by SO(10), and gravity, which we're still unsure about . (GR doesn't work immediately after the big bang, so we really don't know what to do.) Today, we know of three forces, plus gravity (= four forces, really). The standard model, which has been tested to extreme accuracy, describes these forces as obeying the symmetry SU(3)xSU(2)xU(1). So, how does one get from SO(10) to SU(3)xSU(2)xU(1)? The answer is symmetry breaking. But now the kicker. The symmetry breaking doesn't have to occur in the same way everywhere in the early universe---just as there are more than one ways to skin a cat, there are more than one ways to break SO(10). And there's no gurantee that the symmetry breaking happened in the same way everywhere in the early universe. We know, at least, that the symmetry breaking happened the same everywhere in the OBSERVABLE universe, but untill we know more about the early universe, it's very hard to say that the universe is completely homogeneous. Assuming a flat (i.e. infinite) universe, the situation is: If we find no evidence for a grand unified theory, then the universe looks exactly the same everywhere, even outside what we can see. All of my arguments earlier still apply. If there is evidence for a grand unified theory, then it is likely that other parts of the universe look extremely different than our little patch.
http://cosmicvariance.com/2007/04/27/how-did-the-universe-start/ Here's a good blog post by Sean Carroll, a very brilliant scientist, about these ideas. You should listen to him before you listen to mePlease Register or Log in to view the hidden image!
As far as I know, the emotionally comforting "cyclic universe" has pretty much been superceded by the prevailing "Big Chill" idea - simply put, the Universe began as some phenomenon that appears to be a Big Bang, and will continue expanding and as particles continue to interact they will reach lower and lower energy states until eventually you have a diffuse field of "cold" particles with a temperature around (slightly higher than) absolute zero. It has always seemed to me that such cyclical ideas are born of the same thumb-sucking psychology that gave us a belief in Eternal Life, of a purpose beyond simply floating about in space consuming other life forms and eventually dying and so on... There are reputable theorists who have strong models to oppose a one-direction expansion, but there's no good reason to believe them. Chances are the narrow window in which life as we know it is possible will end up being a temporary state. Conclusion - our eternal fate at least as matter goes is cold and dead, expanding outward forever into nothingness.
I prefer the "we don't know yet" position in this, because we don't. About the names: we have the term "multiverse", don't we? Please Register or Log in to view the hidden image!
Since I have finally reached the magic number and can now post links I have a couple that I found helpful in weeding out the various theories that abound on the web. http://www.math.ucr.edu/home/baez/RelWWW/ http://www.astro.ucla.edu/~wright/cosmolog.htm I also like to use NASA's website for answers to questions about the universe. As well as keeping up to date on the missions they are currently performing. It is a large site and to find a particular subject use the search function. http://www.nasa.gov/
I guess what I was trying to say was as follows: As we proceed down the path of discovering our origins, we must be careful not to allow our assumptions, no matter how precious or comforting, to guide our conclusions. In other words, if it all turns out to be a big, cold, dead accident with absolutely no purpose whatsoever, and no God watching it all proudly from above, then we need to be honest with ourselves and accept the truth we have set out to discover. ...we may just find out we are not alone, that the universe is teeming with life and we are a part of a grand evolution - grander than any conceivable earth-bound process. It's like our cosmic scratch-off ticket. Those who aren't courageous enough to find out the truth need not pull out their quarters and pretend to be scientists.
By using concepts like in,out we can find at least two logical connectives, which are XOR and NXOR. Let a thing be something OR nothing. XOR is the logical connective of locality, where a local thing is in XOR out. The truth table of locality is: in out 0 0 → F 0 1 → T (in , out are not the same) = { }_ 1 0 → T (in , out are not the same) = {_} 1 1 → F NXOR is the logical connective of non-locality, where a non-local thing is in NXOR out. The truth table of non-locality is: in out 0 0 → T (in , out are the same) = { } 0 1 → F 1 0 → F 1 1 → T (in , out are the same) = { } I think that what is called the universe is a complementation between locality and non-locality. So, the universe is both a non-finite collection of local things (where each one of them is in XOR out any given local thing) and a non-local thing that is in NXOR out any given local thing. From a non-local point of view, the question "What can be beyond the universe?" is meaningless, and from a local point of view any non-finite collection is incomplete if it is compared to non-locality (from this point of view, a non-finite collection is simply a mathematical entity that its final member does not exist (or in other words, it is a natural-open mathermatical entity)).
what is beyond universe? well I heared that they have discovered that our galaxies are maintaining themselves because of the black matter, apart from gravitation. What can be bayond our universe (which is growing constantly after big bang) can be a balck matter and nothing more. when energy form big bang is spreading its changing the structure of black matter. just my theory
Resurrecting a four year old thread isn't very smart. Especially when: Isn't a theory at all but uninformed speculation. What evidence do you have for your "theory"?
of course its a speculation. in that matter its difficult to speak about any evidence. I base my speculation on that what I have heard recently about black matter and about that the universe has finish. what we know is that galaxies are placed among black matter, so if the univers as we know it is full of galaxies and black matter and if You think that where it ends there are no galaxies, so there has to be just black matter. simple
Why should this be the case since you've already said that I.e. the only place we find dark matter is intermingled with ordinary matter. This is like suggesting that since we find milk mixed in with coffee there should only be milk outside of the coffee cup.
It's one of those utterly meaningless questions. There's a thread somewhere discussing it.If you can find it it's worth a look.
If I may give just one idea that might lie beyond our own , a multiverse could exist beyond. Here read about it. http://en.wikipedia.org/wiki/Multiverse
I have a question that maybe You can help me find an answer for. Why all the galaxies has a shape of circle and all the planets are round? does that depend on gravitation?
