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redhedkangaro
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Many people say that the Universe essentially arose from nothing. Does anyone know if it is possible for "nothing" to be created?
redhedkangaro said:Many people say that the Universe essentially arose from nothing...
marcus said:I don't know any who say the universe arose from nothing.
If you do, could you find us an article where there is some quote to that effect?
It would surprise me and would be quite interesting, if you could find some reputable person really saying that
because the standard cosmo model that they pretty much all use does NOT say that about "arose from nothing."
My impression is that "arose from nothing" is popular BS or some kind of infectious misconception. But I'd be glad to
see some recent professional article that confirms what you say.
marcus said:Do any professional cosmologists say this? I wouldn't go ... by what was written 5 or 10 years ago...
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xantox said:A famous one is:
A. Vilenkin, "Creation of universe from nothing", Phys. Lett. B, 117B, 25-28 (1982).
But see also, using other words but with similar meaning:
S. W. Hawking, N. Turok, "Open inflation without false vacua", Phys. Lett. B, 425, 25 (1998).
The meaning of "nothing" is here extremely qualified, eg it means that the classical 3-geometry and matter vanishes entirely. This should be taken not as a way open towards cheap philosophy, but quite to the opposite, as an opportunity to doubt that the very concept of "nothing" may have an absolute physical scope.
marcus said:Anything professional from > 2004?
I'd be interested!
xantox said:A very interesting one is R. Bousso, "Holographic Probabilities in Eternal Inflation", Physical Rev. Lett., 97-19, (2006).
Actually, not. It really describes several disconnected regions nucleating "from nothing". If you really need the quoted term here, it appears briefly in a related paper by R. Bousso, B. Freivogel, I-S. Yang, "Eternal Inflation: The Inside Story", Phys. Rev. D74-10 (2006), but even if it is not spelled out as such in that and in several other papers, that is what the equations mean essentially. Note that Bousso has worked closely with Hawking and then Linde who both strongly supported such ideas. This is just one example, variants of this beautiful approach have in fact become rather common.marcus said:And that is an example of where our expansion episode arises from something, an occurrence in some other part of of the universe.
xantox said:Again, "nothing" is here perfectly soundly defined as meaning "vanishing classical spacetime and matter".
xantox said:If you really need the quoted term here, it appears briefly in a related paper by R. Bousso, B. Freivogel, I-S. Yang, "Eternal Inflation: The Inside Story", Phys. Rev. D74-10 (2006),...
Here some quotes at random, it is a frequently used term in the literature.marcus said:Where? I looked thru the whole article and could not find anywhere they say the universe arose from nothing.
I must insist on the physical definition of the word "nothing" in all the above quotes as meaning the vanishing of classical spacetime and matter.marcus said:The whole article is about a very definite idea of the something from which they think the universe could have arisen!
This is also the way I've learned to think about "the universe came from nothing" or "spontaneous particle generation" statements. There's always some sort of 'nonclassical' mathematical model that "nothing" or "spontaneous" refers to -- and those models are, as you point out, "very much something".marcus said:When one looks at what they actually say one sees that there is a lot of structure postulated in the pre-bigbang state. Very much something.
I think what you present as THE definition of nothing is your own private definition . Simply the absence of ordinary matter and the failure of spacetime to be classical is not what many experts would call nothing.
marcus said:The point I made earlier was that people used to talk this way particularly in the 1980s and 1990s, but it seems to have gone out of fashion. [..] Inverted commas used like that means not really but in a manner of speaking [..]
ThomasT said:... I also think that it's a good thing (ie., confusion and obfuscation is minimized) when physicists, cosmologists, etc. avoid appropriating (or misappropriating) ordinary language terms to refer to theoretical inventions (even though the practice usually serves some mnemonic purpose).
ThomasT said:... There's always some sort of 'nonclassical' mathematical model that "nothing" or "spontaneous" refers to -- and those models are, as you point out, "very much something".
Regarding redhedkangaro's question -- "Does anyone know if it is possible for 'nothing' to be created? --
It is true that it is less used, I did not oppose that. But note that the originators did not apparently consider it a misnomer at all, as Vilenkin considers it literally nothing, such as in "nothing is nothing". While it is true that this choice of term was also a way to emphasize the provocative character of the new proposal, it should also be carefully considered that "vanishing of classical fields" is a rather good physical definition of "no-existing-thing", "things" being implicitly classical entities in spacetime and unless we can try to come up with an even better physical statement roughly corresponding to the everyday word "nothing" which however I don't know of. There is a respectable western philosophical tradition, which you're in fact following, believing to be able to define more absolute notions of 'nothing' on purely logical terms but which I consider profoundly misguided.marcus said:But since 2000 they do that less and less. Since 2005, as far as I know, not at all. And I think with good reason. Calling such conditions "nothing" is a misnomer and misleads people.
Thank you, but it's not xantox' definition but Vilenkin'. Note that I'm not arguing to affirm my personal views or to contradict yours but to restate those historical facts which originated the expression discussed in this thread. Also, no final word has been spoken on tunnelling theories which remain extremely attractive and it would seem likely that they will also at some point get restated as approximations of newer theories.marcus said:The Loop people call this a quantum regime---a brief period when geometry is not governed by classical GR but functions according to a quantum version of GR. They don't call it 'nothing' even tho it satisfies xantox' definition! This is only one example, and is well known.
xantox said:It is perhaps not entirely semantically random that Loll wrote an article in 2007 and gave a conference in 2002 on the theme "Spacetime from nothing".
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xantox said:It is true that it is less used, .
ThomasT said:... it's a good thing (ie., confusion and obfuscation is minimized) when physicists, cosmologists, etc. avoid appropriating (or misappropriating) ordinary language terms to refer to theoretical inventions...
hurk4 said:Yes Thomas,
I agree, it would be better if ordinary people were not annoyed by inventions by scientists, inventions they define or mention “nothing”. ... By the way what did redhedkangaro mean with his understanding of his "nothing"?
v2kkim said:... One of my christian friend said, the initial state of big bang is the soul of God...
Here you use "nothing" in a purely logical definition applied to the theory itself. The point I was trying to make is that the only meaningful use of "nothing" in physical terms is here actually the one corresponding to Vilenkin' definition.marcus said:Loll's simulations do not start from nothing.
Quantum Raumzeit aus dem "Nichts", Spektrum der Wissenschaft 3/2007.What is the 2007 article where she says 'emerged from nothing'?
xantox said:Quantum Raumzeit aus dem "Nichts", Spektrum der Wissenschaft 3/2007.
That's where it was published. The conference was for a specialist audience however, so possibly in both cases the title was her choice, in which case I don't believe she would choose entirely misguided and inaccurate terms even when addressing to non-technical readers. Anyway, that's not so important. The interesting point here was that CDT and unlike LQC has some very similar features to Vilenkin's wavefunction.marcus said:That's not a scientific journal. Spek der Wiss is a pop-sci magazine! It's like Scientific American only it can even get more sensationalist and inaccurate.
There must be hundreds of papers even after 2000 quoting this term when referring to the tunnelling theories and their related variants up to string cosmology, for obvious historical reasons. But what should be understood here, is that Vilenkin and Hawking chose on purpose to refer to a state devoid of classical spacetime as 'nothing', and that's a subtle and provocative choice of term which deserves discussion, unless you consider they were so intellectually confused that they did not notice that the wavefunction in the forbidden classical state "is something". Fashions, LQC or Penrose have nothing to do with this.marcus said:You are the only person clinging to what you call "Vilenkin's definition". It is obsolete. To find an actual quote from Vilenkin defining nothing the way you like, you'd prob'ly have to go back before 2000.
xantox said:....So, the confusion in the use of this terminology (and I agree there is a confusion, so better avoiding it so everyone will be happy, but disagreement is always good as it can usually lead to more fine-grained concepts) is not originating from Vilenkin' physical definition, as you believe. The confusion is originating, to the opposite, from the false philosophical belief that concepts like "nothing" or "exist" could possibly receive an absolute physical meaning. ...
Carid said:"Thing" is something we can stick a mental label on; this allows us to categorise. This "thing" is different from/the same as that "thing".
The Universe is made up of both something and nothing. Something refers to matter, energy, and all the visible objects in the Universe such as stars, planets, and galaxies. Nothing refers to the vast expanse of empty space between these objects.
The current leading theory is the Big Bang theory, which states that the Universe began as a singularity - a point of infinite density and temperature. This singularity then expanded and cooled, leading to the formation of galaxies and other structures we see today.
Dark matter and dark energy are two mysterious substances that make up a large portion of the Universe. Dark matter is believed to make up about 27% of the Universe and is responsible for the structure and formation of galaxies. Dark energy, on the other hand, makes up about 68% of the Universe and is responsible for the observed accelerated expansion of the Universe.
It is currently unknown whether the Universe is infinite or finite. According to the leading inflationary theory, the observable Universe is finite but the entire Universe may be infinite. However, this is still a topic of ongoing research and debate among scientists.
Based on current observations and theories, it is predicted that the Universe will continue to expand indefinitely, with the galaxies moving further and further apart until they are no longer visible from each other. This is known as the "heat death" of the Universe, where all matter and energy is evenly distributed and the Universe reaches a state of maximum entropy.