crossconnects writes to mention that Discovery is reporting that astronomers have found a nearby star with a mild surface temperature of 660 degrees fahrenheit. "The spectacularly unspectacular object is of special interest because it falls right smack in the middle of the final frontier that divides mega-planets from the puniest stars. Stars in that realm theoretically qualify as an entirely new stellar type -- what's called a Y class dwarf."
Venus just sits there, and greenhouse collects heat, while the Sun is essentially this ginormous H-bomb! Come on, which is cooler? A bomb, or a passive collector of heat?
I thought the definition for a star was that there had to be fusion occurring at its core. TFA doesn't mention it, but I'm amazed that this object can be this cool, yet still have a nuclear furnace at its heart.
I agree, that was what surprised me the most and I was also surprised the article didn't mention that, because to me that's not what I would have expected in this case.
Stars above about 13 jupiter masses fuse deuterium and above 65 jupiter masses also fuse lithium, according to Wikipedia [wikipedia.org]. Below 13 jupiter masses, well, it's hard to say...
If you don't have much fusion, and not very much convection within the star, then the heat gets to the surface very slowly (it can take up to billions of years!), and distributed along the while surface the energy stream is low.
FTA:That means any water in there atmospheres will condense into droplets of water vapor
Aside from the bad English, the quoted bit is actually the most interesting part of the article. Does that mean that a particularly low-temp one of this newly discovered kind of dwarf star could be a self-contained biosphere, with a source of heat in the center surrounded by a life-sustaining atmosphere with liquid water in it?
Dyson Sphere is to Ringworld as Cool Dwarf is to Smoke Ring!:)
The bad English is sad -- you would think that they'd employ a copy editor.
But that wouldn't do anything to prevent using that image and caption. The image is of something bizarre, a red planet-looking thing with something spouting from the poles. It looks more like a candy in a clear plastic wrapper than an extra-cold star.
And the caption is even worse. Put a picture of a red candy with the caption "Ambiuguous Star", and I'm not thinking astronomy. I'm thinking Katamari. Royal Rainbow! [xkcd.com]
While the conditions are almost there for life similar to that of Earth to develop, the problem is that there are a lot of 'almosts', and I'm willing to bet that almost won't cut it in this case. Just two of the things that would probably cause problems is that it is likely a very turbulent atmosphere when compared to that of Earth, and of course, there is also the likely high amount of radiation that is bouncing around (it is a star after all).
If we are thinking DNA/RNA based life, the radiation involved wo
Radiation? The only radiation source is fusion at the core of the star, The only thing this star radiates is Infrared. i.e. Heat. to get any ionizing radiation, youd prolly have to be near the core. It probably looks like a particularly active really big gas giant.
That is a good point, I forgot that it is mostly infrared radiation. However, just because there is no visible light, does that mean it is generating no radiation above the visible spectrum? I'm assuming that this star is fusing Deuterium and Tritium, which I believe does produce Gamma Rays.
Brown dwarfs have been observed to produce X-rays and Gamma rays. So just because this one produces no visible light does not mean it isn't producing a large amount of high energy radiation.
while the conditions woud be extreme, there is Earth life that lives in and around volcanic vents and there are bacteria that are resistant to radiation. If the surface is *only* 660C, there's not a lot of fusion going on and there's likely a very thick and dense shield between the barely fusing core and the surface, so life is not entirely out of the question.
while the conditions woud be extreme, there is Earth life that lives in and around volcanic vents and there are bacteria that are resistant to radiation. If the surface is *only* 660C, there's not a lot of fusion going on and there's likely a very thick and dense shield between the barely fusing core and the surface, so life is not entirely out of the question.
That is true, however I think it is important to note that the expectation is that life did not originate from the area surrounding those volcanic ve
I'll certainly agree that the odds are truly miniscule and that if there is life there, it would be strange even compared to the extremophiles on Earth.
I suppose I'm speculating without expectation, sort of the way Niven liked to imagine very odd but habitable worlds.
If, indeed there are stars a couple hundred degrees cooler still, then it becomes more probable, but still with the problem of how would it evolve in the first place.
Your suggestion that a habitable band would be deeper in is a good one,
Then we should use Degrees Delisle, which has the added bonus of going backwards. Body temperature is at 95 Delisle. The sun (ours, that is) is at negative several thousand degrees Delisle.
Even with an American audience at the temperatures discussed Fahrenheit has no real meaning. The usefulness of Fahrenheit is how the range of 0 - 100 reflects weather temperatures people have experienced. Temperatures beyond common experience are better expressed in Celsius.
In a scientific article, I would expect stellar temperatures to be given in Kelvins.
In a popular article, Celsius or Fahrenheit (depending on country) are probably expected and more understandable to a general audience.
Ideally, any good article would give the measurement or estimate in the original units first (and with the original degree of precision), followed by a conversion if needed for the expected audience.
600 F has no meaning? The dial on my oven goes up to 600 degrees. It's also the temperature gasoline ignites at. We are hardly talking about astronomical temperatures beyond our comprehension.
To some degree, you are correct; American scientists, the target audience of the original publication, would prefer the Kelvin unit, which was indeed used in the original publication. However, I don't think the Discovery channel's target audience is primarily scientists but rather the American public, which prefers Farenheit - hence the use of that unit on the Discovery channel's website (the location of TFA).
Well, in the context, it makes about as much sense as the Kelvin scale... an arbitrary step size with absolute zero being the zero point. Sounds sensible to me! Probably would be better than Celsius or Fahrenheit.
Alas, Kelvin got there ten years earlier, so it's the Celsius scale's step size for the accepted absolute scale. Still a bit arbitrary.
Perhaps we should come up with a new scale that encompasses absolute zero and a very well defined temperature that makes sense on an absolute/astronomical leve
The "temperature" of the Big Bang is the theoretical hottest you can ever get, since at that point all mass was in the form of energy, and therefore you had the maximum energy at the maximum density. Nothing can ever exceed that. Thus, if you knew what that was, you could assign it a fixed value as your upper end of the scale. The ideal would be to then have a set of functions (linear, logarithmic, whatever), where a given function was selected for a specific type of application, with the exception of some specific function chosen as the 'standard'.
The "temperature" of the Big Bang is the theoretical hottest you can ever get, since at that point all mass was in the form of energy, and therefore you had the maximum energy at the maximum density. Nothing can ever exceed that.
Since the volume of space at t=0 was zero, but the energy content was not, the temperature at t=0 is infinite. That isn't useful for determining a scale. Alternatively, if the energy content was zero, then the temperature is lim(x->0) x/x, which is 0. If energy is zero but vo
That assumes a singularity at t=0, which Professor Hawking has provided a convincing case against. (As t approaches 0, space/time becomes parabolic, which means there is no requirement for a discontinuity and no requirement for a point of creation. He's usually quoted as having said that he's glad Pope John Paul - whom he visited shortly after giving that particular talk - had not heard that particular result at that time.)
It also assumes it's useful to go back to a t=0, assuming one exists. Theoretical m
but the energy content was not, the temperature at t=0 is infinite.
Okay, at time t= +e(psilon), wiseguy.:).
Of course, this quantity already goes by the name "Planck temperature",
so we have a nice tidy number: 1.417 x10^32 Kelvin.
How are you going to make such a scale any less arbitrary
than Kelvin scale
Well, any value on that scale gives a meaningful number in the sense
that it expresses the portion of the maximum energy possible in this
universe, with a well-behaved upper (100) and lower (0) b
I say we use 0 for absolute 0 and 1 for the Planck temperature. Then the weather difference here in North Dakota, from one day to the next would be so small that it wouldn't seem daunting. I'd feel much better with a 1.2x10^32 temperature drop than a 50 degree drop.
Planck's temperature is theoretically the hottest anything can possibly be at - 1.41679 X 10^32 K. Beyond that, and the energy density will basically generate enough gravity that it collapses into a black hole. (We're talking "Big Bang" energy density here.) Mater == energy, energy == matter, and enough of either in a small enough volume will collapse into a singularity.
So - if you want a possible temp scale, use 0K as starting point, Planck temperature at end, and add convenient subdivisions. But, rememb
The "right" unit of temperature measurement would be eV, or the Planck system of units. That's right: units of energy. It gives twice the average energy per degree of freedom of an object at said temperature. In this system, the Boltzmann constant would be equal to 1, as it should be and would have been had we known chemistry before coming up with the idea of "temperature".
Room temperature is about 1/40 eV on this scale, or 25.3 meV. Water boils at 32.2 meV and freezes at 23.5 meV. Absolute zero is, of c
by Anonymous Coward
on Monday April 14 2008, @04:19PM (#23069648)
... and I have a hard time believing there are many stars out there that are even "as cool" as Venus. Venus is so fucking awesome that it's just absurd for anybody to claim they've found a star cooler than her.
Not that hard (Score:5, Funny)
Re:Not that hard (Score:5, Funny)
Parent
After... (Score:1)
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Fry: Oh. What's it called now?
Professor Hubert Farnsworth: Urrectum.
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Venus just sits there, and greenhouse collects heat, while the Sun is essentially this ginormous H-bomb!
Come on, which is cooler? A bomb, or a passive collector of heat?
Publication at arXiv.org (Score:5, Informative)
http://arxiv.org/abs/0802.4387 [arxiv.org]
http://arxiv.org/pdf/0802.4387v2 [arxiv.org]
Nuclear fusion? (Score:5, Interesting)
Fascinating stuff indeed.
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Re:Nuclear fusion? (Score:5, Informative)
Parent
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Re:Nuclear fusion? (Score:4, Funny)
Perhaps it's using cold fusion? (ba dump dum)
Parent
Re:Nuclear fusion? (Score:5, Funny)
Parent
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Sigh, Bad English / Hmm - Biosphere? (Score:5, Interesting)
Aside from the bad English, the quoted bit is actually the most interesting part of the article. Does that mean that a particularly low-temp one of this newly discovered kind of dwarf star could be a self-contained biosphere, with a source of heat in the center surrounded by a life-sustaining atmosphere with liquid water in it?
Dyson Sphere is to Ringworld as Cool Dwarf is to Smoke Ring!
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But that wouldn't do anything to prevent using that image and caption. The image is of something bizarre, a red planet-looking thing with something spouting from the poles. It looks more like a candy in a clear plastic wrapper than an extra-cold star.
And the caption is even worse. Put a picture of a red candy with the caption "Ambiuguous Star", and I'm not thinking astronomy. I'm thinking Katamari. Royal Rainbow! [xkcd.com]
your anagram (Score:1)
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Just two of the things that would probably cause problems is that it is likely a very turbulent atmosphere when compared to that of Earth, and of course, there is also the likely high amount of radiation that is bouncing around (it is a star after all).
If we are thinking DNA/RNA based life, the radiation involved wo
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So, you're saying it's a biosphere of roaches, then....?
Layne
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Brown dwarfs have been observed to produce X-rays and Gamma rays. So just because this one produces no visible light does not mean it isn't producing a large amount of high energy radiation.
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while the conditions woud be extreme, there is Earth life that lives in and around volcanic vents and there are bacteria that are resistant to radiation. If the surface is *only* 660C, there's not a lot of fusion going on and there's likely a very thick and dense shield between the barely fusing core and the surface, so life is not entirely out of the question.
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That is true, however I think it is important to note that the expectation is that life did not originate from the area surrounding those volcanic ve
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I'll certainly agree that the odds are truly miniscule and that if there is life there, it would be strange even compared to the extremophiles on Earth.
I suppose I'm speculating without expectation, sort of the way Niven liked to imagine very odd but habitable worlds.
If, indeed there are stars a couple hundred degrees cooler still, then it becomes more probable, but still with the problem of how would it evolve in the first place.
Your suggestion that a habitable band would be deeper in is a good one,
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Fahrenheit is much funner to say than Celsius, or *wretch* Centigrade.... those sound like crap.
J
Re:Fahrenheit (Score:4, Funny)
Parent
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The usefulness of Fahrenheit is how the range of 0 - 100 reflects weather temperatures people have experienced.
Temperatures beyond common experience are better expressed in Celsius.
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In a popular article, Celsius or Fahrenheit (depending on country) are probably expected and more understandable to a general audience.
Ideally, any good article would give the measurement or estimate in the original units first (and with the original degree of precision), followed by a conversion if needed for the expected audience.
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Discovery Channel's Target Audience != Scientists (Score:3, Insightful)
Re:Fahrenheit (Score:4, Funny)
Parent
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What, they should have used Rankine?
Well, in the context, it makes about as much sense as the Kelvin scale... an arbitrary step size with absolute zero being the zero point. Sounds sensible to me! Probably would be better than Celsius or Fahrenheit. Alas, Kelvin got there ten years earlier, so it's the Celsius scale's step size for the accepted absolute scale. Still a bit arbitrary. Perhaps we should come up with a new scale that encompasses absolute zero and a very well defined temperature that makes sense on an absolute/astronomical leve
Re:Fahrenheit (Score:4, Interesting)
Parent
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Since the volume of space at t=0 was zero, but the energy content was not, the temperature at t=0 is infinite. That isn't useful for determining a scale. Alternatively, if the energy content was zero, then the temperature is lim(x->0) x/x, which is 0. If energy is zero but vo
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It also assumes it's useful to go back to a t=0, assuming one exists. Theoretical m
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Okay, at time t= +e(psilon), wiseguy.
Of course, this quantity already goes by the name "Planck temperature", so we have a nice tidy number: 1.417 x10^32 Kelvin.
How are you going to make such a scale any less arbitrary than Kelvin scale
Well, any value on that scale gives a meaningful number in the sense that it expresses the portion of the maximum energy possible in this universe, with a well-behaved upper (100) and lower (0) b
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Plank's Temperature (Score:2)
Mater == energy, energy == matter, and enough of either in a small enough volume will collapse into a singularity.
So - if you want a possible temp scale, use 0K as starting point, Planck temperature at end, and add convenient subdivisions. But, rememb
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Room temperature is about 1/40 eV on this scale, or 25.3 meV. Water boils at 32.2 meV and freezes at 23.5 meV. Absolute zero is, of c
I'm one of Venus' best friends... (Score:3, Funny)