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How long will the sun remain a white dwarf?
Paul Schlyter wrote: At the start, the temperature difference is 100 deg C of course. Let's say after one hour the temperature difference is 10 degrees. After two hours it's 1 degree, after three hours 0.1 degrees, after four hours 1E-2 degrees. After a day+night the temperature difference is 1E-22 degrees, after a week 1E-166 degrees, after a year 1E-8764 degrees, and after 15 billion years 1E-131490000000000 degrees. The temperature difference will never ever go all the way to zero! This assumes that the quantum of temperature is smaller than 10^-131490000000000 degrees... -- Guy Macon http://www.guymacon.com/ |
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How long will the sun remain a white dwarf?
Paul Schlyter wrote: (snip) Paul please read the following references in order to improve the quality of your posts:: Quoting Style in Newsgroup Postings http://www.xs4all.nl/%7ewijnands/nnq/nquote.html How do I quote correctly in usenet? http://www.netmeister.org/news/learn2quote2.html Common Mistakes in Usenet Postings and How to Avoid Them http://www.complang.tuwien.ac.at/ant...s.html#quoting Bottom vs. top posting and quotation style on Usenet http://www.cs.tut.fi/~jkorpela/usenet/brox.html Why bottom-posting is better than top-posting http://www.caliburn.nl/topposting.html +What do you mean "my reply is upside-down"? http://www.i-hate-computers.demon.co.uk/quote.html Put an end to Outlook Express's messy quotes with this automated fix! http://home.in.tum.de/~jain/software/oe-quotefix/ |
#13
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How long will the sun remain a white dwarf?
On 13 juuli, 22:45, Radium wrote:
Hi: When the sun becomes a white dwarf, approximately how long will it take for it to cool off to a cold black dwarf that does not emit anymore heat or light [or other energies] than the surrounding space? Thanks, Radium Would there ever be a time when the emitted heat of the white dwarf is significantly less than incident relict radiation? The white dwarf is cooling, but so is relict radiation... |
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How long will the sun remain a white dwarf?
On Mon, 16 Jul 2007 08:39:07 -0700, Crown-Horned Snorkack
wrote: Would there ever be a time when the emitted heat of the white dwarf is significantly less than incident relict radiation? The white dwarf is cooling, but so is relict radiation... Unless you can propose some active cooling mechanism (that is, something other than passive radiation), it would violate the second law of thermodynamics for the white dwarf to become cooler than the temperature of the Universe as measured from the white dwarf's location (which in all likelihood will be very close to the average relict radiation temperature). The white dwarf will remain forever warmer than the background. _________________________________________________ Chris L Peterson Cloudbait Observatory http://www.cloudbait.com |
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How long will the sun remain a white dwarf?
On 16 juuli, 19:08, Chris L Peterson wrote:
On Mon, 16 Jul 2007 08:39:07 -0700, Crown-Horned Snorkack wrote: Would there ever be a time when the emitted heat of the white dwarf is significantly less than incident relict radiation? The white dwarf is cooling, but so is relict radiation... Unless you can propose some active cooling mechanism (that is, something other than passive radiation), it would violate the second law of thermodynamics for the white dwarf to become cooler than the temperature of the Universe as measured from the white dwarf's location (which in all likelihood will be very close to the average relict radiation temperature). The white dwarf will remain forever warmer than the background. And Earth is forever warmer than background. However, geothermal heat is negligible compared to incident light of Sun. Would the white dwarf cool to a point where its loss of internal heat is smaller than the incident relict radiation? |
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How long will the sun remain a white dwarf?
On Fri, 13 Jul 2007 19:45:36 -0000, Radium
wrote: Hi: When the sun becomes a white dwarf, approximately how long will it take for it to cool off to a cold black dwarf that does not emit anymore heat or light [or other energies] than the surrounding space? Thanks, Radium Hasn't the recent discovery that the Universe's expanse is accelerating put an upper limit on the lifetime of the Unverse? Or at least the lifetime before every particle is froced apart from al te particles? Of course I'm sure that with in another 20 years someone will make another discovery which will throw that model out as well. |
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How long will the sun remain a white dwarf?
On Wed, 18 Jul 2007 00:49:53 -0700, Crown-Horned Snorkack
wrote: And Earth is forever warmer than background. However, geothermal heat is negligible compared to incident light of Sun. Not so. The Earth gives up more heat than it receives from the Sun. It is slowly cooling. The Sun provides nowhere near enough energy to heat the Earth above its current temperature. Don't confuse the temperature of the Earth as a whole, which is determined by residual heat of formation and by internal radioactive processes, with the surface and atmospheric temperature, which is determined largely by solar radiation. Would the white dwarf cool to a point where its loss of internal heat is smaller than the incident relict radiation? Again, that would violate the second law. Heat flows from warm to cold, not the other way. The white dwarf will spend eternity with its temperature asymptotically approaching its surrounding temperature. It can never get colder than the background, unless some cosmic refrigerator comes along and actively pumps heat out of it. _________________________________________________ Chris L Peterson Cloudbait Observatory http://www.cloudbait.com |
#19
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How long will the sun remain a white dwarf?
In article ,
Chris L Peterson wrote: On Wed, 18 Jul 2007 00:49:53 -0700, Crown-Horned Snorkack wrote: And Earth is forever warmer than background. However, geothermal heat is negligible compared to incident light of Sun. Not so. The Earth gives up more heat than it receives from the Sun. It is slowly cooling. The Sun provides nowhere near enough energy to heat the Earth above its current temperature. Don't confuse the temperature of the Earth as a whole, which is determined by residual heat of formation and by internal radioactive processes, with the surface and atmospheric temperature, which is determined largely by solar radiation. .....which means the geothermal heat flow is negligible compared to the radiation heat flow from the Sun onto the Earth, and from the Earth out into speace. Or else, geothermal heat would need to be taken into account by meteorologists when forecasting the weather. Only on small parts of the Earth (e.g. on Iceland), geothermal heat flow is non-negligible on the Earth's surface. -- ---------------------------------------------------------------- Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN e-mail: pausch at stockholm dot bostream dot se WWW: http://stjarnhimlen.se/ |
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How long will the sun remain a white dwarf?
On Fri, 20 Jul 2007 09:12:35 GMT, (Paul Schlyter) wrote:
....which means the geothermal heat flow is negligible compared to the radiation heat flow from the Sun onto the Earth, and from the Earth out into speace... Good thing, too, since the average (bulk) temperature of the Earth is well over 3000°C. Talk about global warming! We're protected by a nice, insulating crust. _________________________________________________ Chris L Peterson Cloudbait Observatory http://www.cloudbait.com |
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