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How long will star formation endure before the eventual heat death of
In article ,
James Goetz writes: Lord Kelvin's prediction of heat death indicates the eventual end to star formation in the observable universe. Have any astrophysicists made any predictions for the endurance of star formation in the observable universe? Or does anybody here want to take a crack at predicting it? [[Mod. note -- 1. This is really an astronomy question rather than a general physics question, so I have set the Followup-To header to point to our sister newsgroup sci.astro.research . 2. As to answering your question: Trying to understand/model the star formation rate of the universe has been a major research area for decades (e.g., try the search term "star formation history of the universe" in google scholar or the ADS). But most of this focuses on the *past* star formation rate. I'm sure there are studies trying to forecast this into the future, but I don't have references handy. -- jt]] Star formation is heavily influenced by galaxy interactions. Thus, one would at least need to run galaxy-evolution simulations into the future, but no-one does this. One reason is that one can't check the simulations by comparing to observations. The other is that with time matter become more and more clumped, so more dynamic range is needed for realistic simulations. (I had never seen this discussed in the literature, but a few years ago I asked some of the main players in the field why this is the case.) |
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How long will star formation endure before the eventual heat death of
Have any astrophysicists made any predictions for the endurance of
star formation in the observable universe? Fred Adams seems to have written a book chapter on the universe's long-term futu http://adsabs.harvard.edu/abs/2012coup.book...71A -- Help keep our newsgroup healthy; please don't feed the trolls. Steve Willner Phone 617-495-7123 Cambridge, MA 02138 USA |
#3
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How long will star formation endure before the eventual heat
On 28/03/2017 18:47, Phillip Helbig (undress to reply) wrote:
In article , James Goetz writes: Lord Kelvin's prediction of heat death indicates the eventual end to star formation in the observable universe. Although he was at the time largely basing his model on the sun burning coal in an attempt to debunk Darwin and the long geological timescales needed for evolution to run its course. Have any astrophysicists made any predictions for the endurance of star formation in the observable universe? Or does anybody here want to take a crack at predicting it? John Baez has a nice page that summarises the demise of the universe which I think is more or less up to date. Ballpark of 10^14 years for normal star formation processes to have essentially run out of steam give or take an order of magnitude or two. http://math.ucr.edu/home/baez/end.html Total evaporation of galaxies feels intuitively wrong to me, but I am sure he really knows what he is talking about. So can someone please explain why when a star is flung out at above escape velocity the remaining stars do not become ever more tightly bound a la globular clusters until eventually core collapse of the remaining ones occurs? (or can the last tight bound pair always fling out a third component) And quite a nice graphic scaled in log(log(t)) to fit everything on: https://en.wikipedia.org/wiki/Graphi..._to_Heat_Death [[Mod. note -- 1. This is really an astronomy question rather than a general physics question, so I have set the Followup-To header to point to our sister newsgroup sci.astro.research . 2. As to answering your question: Trying to understand/model the star formation rate of the universe has been a major research area for decades (e.g., try the search term "star formation history of the universe" in google scholar or the ADS). But most of this focuses on the *past* star formation rate. I'm sure there are studies trying to forecast this into the future, but I don't have references handy. -- jt]] Star formation is heavily influenced by galaxy interactions. Thus, one would at least need to run galaxy-evolution simulations into the future, but no-one does this. One reason is that one can't check the simulations by comparing to observations. The other is that with time matter become more and more clumped, so more dynamic range is needed for realistic simulations. (I had never seen this discussed in the literature, but a few years ago I asked some of the main players in the field why this is the case.) Galaxy galaxy collisions and supernova shockwaves are very helpful to star formation but massive stars are short lived so eventually it is all the dim barely lit stars, white dwarfs and neutron stars that will predominate as long term survivors into the later degenerate era. -- Regards, Martin Brown |
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How long will star formation endure before the eventual heat
Le 28/03/2017 =E0 19:47, Phillip Helbig (undress to reply) a =E9crit :
2. As to answering your question: Trying to understand/model the star formation rate of the universe has been a major research area for decades (e.g., try the search term "star formation history of the uni= verse" in google scholar or the ADS). But most of this focuses on the *past= * star formation rate. I'm sure there are studies trying to forecast this into the future, but I don't have references handy. -- jt]] Yes, the past is easier to read than the future. The future of the Universe? I do not see any data that we could gather that could answer that question. Even trying to figure out the observable universe is hard to do for the future. With most theories in a state of flux, dark matter, dark energy... we are in the dark and there is no scientific answer to that question now. Scientists shouldn't be afraid of saying "I do not know" when that is the case. And the future of the universe, the origin of life and man, are till now unanswered questions. Nobody knows. Can research about the future of the observable universe be done now? Yes, we can extrapolate "some day the energy will be used up and will provoke the lights going out". The thermical death of thermodynamics, we are doomed. This has been proposed (in diverse forms) since ages. And all those speculations are correct within the frames of their respective theories, that get soon obsolete, as knowledge advances. [[Mod. note -- I think the author's last sentence is quite similar to a classic logical fallacy, conflating different "amounts of wrongness". The late Isaac Asimov wrote a far better explanation of, and rejoinder to, this fallacy than anything I could write, and I think his essay is very relevant he Isaac Asimov "The Relativity of Wrong" The Skeptical Inquirer, Fall 1989, Vol. 14, No. 1, Pp. 35-44 http://chem.tufts.edu/AnswersInScien...ityofWrong.htm -- jt]] |
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How long will star formation endure before the eventual heat
Le 31/03/2017 =E0 01:25, jacobnavia a =E9crit :
[[Mod. note -- I think the author's last sentence is quite similar to a classic logical fallacy, conflating different "amounts of wrongness". The late Isaac Asimov wrote a far better explanation of, and rejoinder to, this fallacy than anything I could write, and I think his essay is very relevant he Isaac Asimov "The Relativity of Wrong" The Skeptical Inquirer, Fall 1989, Vol. 14, No. 1, Pp. 35-44 http://chem.tufts.edu/AnswersInScien...vityofWrong.ht From that text: quote The basic trouble, you see, is that people think that "right" and "wrong" are absolute; that everything that isn't perfectly and completely right is totally and equally wrong. end quote Kepler's laws are confirmed by stars moving around the central black hole of the galaxy. Ellipses, as he proposed.Those laws are based on observations that astronomers have done. The fate of the observable Universe in X trillion years? What observations can you present, that would authorize some human to postulate anything about that? This is ridiculous, with space telescopes only 25 years old, and with a species that has never got further than its small satelite at 300 000 Km. I just said: Scientists shouldn't be afraid of saying I don't know when that is the case: they haven't any observational data to establish any theories about the subject matter. That would stop all kinds of futile speculations without any data. |
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