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Topic: How big is the universe? (Read 2753 times) |
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Bass
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Re:How big is the universe?
« Reply #15 on: 2006-12-23 18:07:00 » |
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Thanks to all here for their views and opinions, it is very interesting.
[Bass 1] I do not doubt by the end of this century that we will either be obliterated or will have some kind of advanced space program.
[Hermit 1] I don't necessarily disagree with you, although there are other alternatives, most of them brutish and nasty, but I do wonder what relationship this thought had to the rest of this?
[Bass 2] I was just having some cynical and thoughts of space vision at the time which somehow found there way into my words here. What other alternatives are there asides from an advanced space program and obliterating ourselves?
Quote from: David Lucifer on 2006-12-23 01:44:33 [Lucifer] The hypothetical external non-universal force doesn't help. What started it?
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Possibly but I do not know of any valid reason which suggests that it does not help, unless I have missed something here. Hermit did mention many reasons why it should not be so, but I'm not quite sure what reasons he meant; I don't really know that much on this subject.
Even if some kind of external non-universal force did exist outside of our universe I don't see how we could ever know of ifs presence. Perhaps if string theory holds up (or M-theory which might be better here) this external force could just be gravity as some kind of superforce, as it passes through multiple dimensions (parallel universes) of our universe and leaking out beyond our known multiverse where membranes are said to exist. Perhaps, if this was so, gravity (outside of our multiverse) would be amplified to a profound degree (thus becoming this super force) and reach its "true" constant force, since it seems (according to some theories) that it is somewhat diluted within our universe because it can escape into higher dimensions of space, passing on into parallel universes. It would help if we knew the speed of gravity too; could it possibly be faster then light? I would have thought so. Personally I don't really see how light can be completely massless although I can see how gravity could, as it could (possibly) pass beyond our physical universe and into another; I don't think light can do this even in theory. If the speed of light is the cosmic speed barrier for everything in the universe with mass then even light would not be able to break its own (universal set) law, which would leave it with mass, however mote. Then if gravity was massless it could travel faster then light, though not in the Newtonian way. I would weyken here that the speed of gravity is set in a given universe by something else, possibly the expansion rate and speed of that universe so that the speed of gravity = the speed of expansion, and I also think I remember reading on how the universe is expanding faster then the speed of light, which is why the universe is black, the information of the darkness we see as space travels faster then light.
To my mind it is very logical to suggest that there is such a thing as an eternity. It would be my guess here that this super force is an eternal force when applied beyond the layers of our multiverse. So nothing would really start it anymore then anything can really create energy; it would just be.
Perhaps in this vast eternal sea of energy, and this super force, super singularities or energy voids naturally form and build up over an indefinite amount of time like expanding bubbles. Then when two of these come into contact with each other they simply collapse in on themselves creating a massive flux of energy imbalance which caused a universal singularity to concentrically ignite again and again from the same point causing multiple big bangs and thus instantiating the multiverse and relative universal space-time. The age of a multiverse would therefore be equal to however long this super singularity or energy void had in expanding before it began to collapse. I do think however that there is more then one way to initiate a big bang; the memebranes in M-theory would be another possible way in which multiverses would collide with each other. But I would guess here that a completely new multiverse is not instantiated, more that the parallel universes contained within it are destroyed in the wake of new ones.
But then the universe could just be endless and infinite in itself.
This is just my own thinking on the matter. I don't really know much about the subject, but I hope this can make for some interesting discussion here.
Regards
Bsss
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Perplextus
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Re:How big is the universe?
« Reply #16 on: 2006-12-30 12:31:06 » |
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Alternatives to the Big-Bang Theory aside, the problem of "what came before the Big Bang" is really only a pseudo-problem. Not because of the notion that events occurring before the instantiation of space-time are nonsensical, but because the notion of the Big Bang as the instantiation of space-time over-steps the limits of what the theory actually states. Did space-time begin with the Big Bang? Indeterminate; the Big Bang is simply the boundary of what is observable. Just because we cannot observe beyond it does not mean it necessarily marks the "beginning" of space-time. Asking what came before the Big Bang is NOT NECESSARILY like asking "what's north of the north pole"; it is really more akin to asking "what's beyond the furthest thing we are physically capable of observing?" Whether or not there were pre-conditions to the Big Bang is not established within the theory; only the impossibility of answering that question is established. For this reason, I find it highly unhelpful to posit the existence of some "supernatural" eternal force as a precursor to the Big Bang; why not simply posit the existence of another universe, such that the annihilation of that universe caused the Big Bang while simultaneously eradicating any observable evidence of that causal event? While still little more than idle (and unfalsifiable, at least for now) speculation, this at least requires a far smaller speculative leap.
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Hermit
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Re:How big is the universe?
« Reply #17 on: 2006-12-30 18:46:47 » |
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[Perplextus said a mouthful, much based on] <snip> Not because of the notion that events occurring before the instantiation of space-time are nonsensical, but because the notion of the Big Bang as the instantiation of space-time over-steps the limits of what the theory actually states. Did space-time begin with the Big Bang? Indeterminate; the Big Bang is simply the boundary of what is observable. Just because we cannot observe beyond it does not mean it necessarily marks the "beginning" of space-time.<snip>
[Hermit] I'd have to disagree. The bounding limit to the observable is the reduction in density to the point where light could pass through the Universe, which was significantly (380kY) post big bang. Nonetheless the preceding events left evidence which COBE and its successor project, WMAP, have gathered. This evidence proved the capability of the QBB theory to make extremely accurate predictions. Refer [ Church of Virus BBS, General, Science & Technology, Age of the Universe, Hermit, 2003-07-04 ] . It is significant to note that when the predictions were first made, in the late 1920s, they were deemed nonsensical and it seemed entirely infeasible to adduce experimental evidence for these predictions. To most people in the field, this greatly strengthens the weight we should grant to these already amazingly precise results.
[Hermit] Given the evidence for the QBB, in which effects and events occurred in a fashion which simply would not be possible in the current Universe, this confirms both the sub-Planck epoch and the Grand Unification Transition, both of which speak volubly to the earlier non-existence of space-time. This is not some hypothetical conclusion, it is evidentially well supported theory. If you don't like the QBB, you have to offer an alternative theory which has the same or better explicatory power, and the same or broader application.
[Hermit] This thread is directly relevant Church of Virus BBS, General, Philosophy & Religion, Does the Second Law of Thermodynamics Prove the Existence of God? and the references at Church of Virus BBS, General Science & Technology, an infinite number of possibilities, Reply #1, Hermit, 2006-04-27 may also be helpful.
My recommended reading list for this subject continues to be:
The First Three Minutes, by Steven Weinberg [recommended by Hermit@lucifer.com]
A very interesting popular book (with no mathematics) is "The Elegant Universe -- Superstrings, Hidden Dimensions, and the Quest for the Ultimate Theory", Prof. Brian Greene. [recommended by rhinoceros@freemail.gr]
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With or without religion, you would have good people doing good things and evil people doing evil things. But for good people to do evil things, that takes religion. - Steven Weinberg, 1999
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Bass
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Re:How big is the universe?
« Reply #18 on: 2006-12-31 05:54:21 » |
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Quote from: Perplextus on 2006-12-30 12:31:06 why not simply posit the existence of another universe, such that the annihilation of that universe caused the Big Bang while simultaneously eradicating any observable evidence of that causal event?
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Logically I agree with you, but this logic (when taken so far) is quite flawed. Why? because you will always have someone who eventually asks "Yeah ok I see what you mean, but where did that other universe come from and the one before that and the one before that?"
Hence some eternal force (what I don't know).
What I was saying was just an example of what could (logically & hypothetically) possibly answer (and end) that question for the people who ask it, whilst not knowing for sure about it.
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Hermit
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Re:How big is the universe?
« Reply #19 on: 2006-12-31 16:42:55 » |
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[Bass] Logically I agree with you, but this logic (when taken so far) is quite flawed. Why? because you will always have someone who eventually asks "Yeah ok I see what you mean, but where did that other universe come from and the one before that and the one before that?"
[Hermit] When space-time did not exist there was no before. Prior to Planck time there was no causuality, no before, no after. No rules of physics applied, indeed, no rules applied except the rule that no rules applied. The Universe arose from a singularity and a singularity has no rules and no other side.
[Hermit] When you look into a mirror, you do not see a world-behind-the-mirror, you see only a reflection of our world. Postulating rules for the world-behind-the-mirror is a meaningless exercise. That world-behind-the-mirror you imagine does not exist. In the same way, when we look into the QBB we see the paths taken from the QBB that lead to the present. These paths were not just possible and sufficient, they were necessary to establish what is. Trying to peer behind the QBB is as meaningless as making up rules for what is behind the mirror. The question, and any putative answers, however phrased, are meaningless.
[Hermit] And of course, postulating an "eternal force" is completely meaningless, because "eternal" merely means "for all time" and when you know that time did not exist (which we do, because time is only how we perceive, however dimly, one attribute of space-time), then you know that "eternal" is not meaningful either. So you are left with "force". But force is an aspect of energy which is an aspect of energy-matter equivalence. In the non-baryonic proto-Universe, this too was meaningless. So now, instead of "eternal force" you have "meaningless meaningless."
[Hermit] This isn't an answer to anything, this an end to meaningful discourse; to suppose that it might be anything else is an admission of idiocy.
Regards
Hermit
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With or without religion, you would have good people doing good things and evil people doing evil things. But for good people to do evil things, that takes religion. - Steven Weinberg, 1999
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Blunderov
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Re:How big is the universe?
« Reply #20 on: 2007-01-01 00:42:17 » |
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Quote from: Hermit on 2006-12-31 16:42:55
...When space-time did not exist there was no before. Prior to Planck time there was no causuality, no before, no after...
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[Blunderov]As the great man said...
http://www.philosophypages.com/hy/6s.htm
"Whereof one cannot speak, thereof one must be silent."
(Tractatus 7) This is a stark message indeed, for it renders literally unspeakable so much of human life. As Wittgenstein's friend and colleague Frank Ramsey put it,
"What we can't say we can't say, and we can't whistle it either."
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Bass
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Re:How big is the universe?
« Reply #21 on: 2007-06-21 14:06:53 » |
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Quote from: Hermit on 2006-12-21 20:33:14 | The speed of light is not a constant. Considering it as such involves a massive and invalid simplification of a much more complex reality. The speed of light depends on many, many factors (media, gravity, relative motion, etc.). |
Greetings Hermit.
This has been weighing on my mind for some time now, and after doing some research on light I'm a little confused with your quote. From what I can tell here, with a little help from Wikipedia on the speed of light:
The speed of light in a vacuum is an important physical constant denoted by the letter c for constant (or the Latin word celeritas meaning "swiftness"). It is the speed of all electromagnetic radiation in a vacuum, including visible light, and more generally it is the speed of anything with zero rest mass.
In metric units, c is exactly 299,792,458 metres per second (1,079,252,848.8 km/h) but 3 \times 10^8 m/s is commonly used in rough estimates. Note that this speed is a definition, not a measurement. Since the fundamental SI unit of length, the metre, has been defined since October 21, 1983 in terms of the speed of light, one metre is the distance light travels in a vacuum in 1/299,792,458 of a second. Thus, any further increase in the precision of the measurement of the speed of light will actually change the length of the metre; the speed of light will remain precisely 299,792,458 m/s. In imperial units, the speed of light is about 186,282.397 miles per second, that is about one foot per nanosecond.
When passing through a transparent or translucent material medium, like glass or air, light will have a slower speed than in a vacuum; the ratio of c to the observed phase velocity is called the refractive index of the medium. In general relativity, a gravitational potential can affect the speed of distant light in a vacuum, but locally light in a vacuum will always pass an observer at a rate of c.
Kind regards,
Bass
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