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Temperature less than absolute zero possible

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enigma10

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doubletruncation

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<font color="yellow">only if it was possible, which it is.</font><br /><br />But it isn't possible, not now, or ever - that was the point. If you *ever* observe a system (now, a trillion years from now, doesn't matter) then it has to have a finite uncertainty in its energy, which means you can't pinpoint its energy to a single exact value, which means that you can't say it's at absolute zero temperature. If something is strictly unobservable, then it may as well be impossible. <div class="Discussion_UserSignature"> </div>
 
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enigma10

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<i>If something is strictly unobservable, then it may as well be impossible. </i><br /><br /><br />lol.. by your own definition, over 90% of the universe must be impossible and therefore cant be possible, thus it cannot exist. <br /><br /> Seriously though, i can see you're one of those that believes it cannot be reached, though your reasons for that belief are no different than the textbook reasons. <br /><br /> Considering we've already come to the 1 cycle needed to breach to absolute zero benchmark, with current technology, i am of strong conviction it can be achieved, someday.<br /> <div class="Discussion_UserSignature"> <em>"<font color="#333399">An organism at war with itself is a doomed organism." - Carl Sagan</font></em> </div>
 
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vogon13

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Smarter folks have sparred and lost to Heisenberg . . . .<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>
 
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doubletruncation

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<font color="yellow">over 90% of the universe must be impossible and therefore cant be possible, thus it cannot exist.</font><br /><br />If something is truly unobservable - meaning it can never have any effect on anything that humans could observe, then there is no way we could ever infer its existence. I don't know how you conclude that 90% of the universe is completely unobserveable; by definition we have no idea if there exists anything that is utterly unobservable. Note that this is different from dark matter or energy or what have you since those do have an observable effect on the universe which is how we infer their existence. Similarly there may exist many stars and exotic things in nature that we haven't observed yet, but we could one day hope to observe them. What I mean by things that are utterly unobservable are for example goblins that only interact with themselves via some 5th force but cannot interact with any of the matter/energy that we are made out of, or parallel universes that are completely off-limits to us - sure they may be out there, but we could never know. Similarly if there is something at exactly absolute zero temperature, then it can never interact with anything, meaning we can never even hope to know about it (let alone create it) - so it really is a pointless argument to debate whether or not there is such a system.<br /><br /><font color="yellow">Considering we've already come to the 1 cycle needed to breach to absolute zero benchmark, with current technology, i am of strong conviction it can be achieved, someday.</font><br /><br />I think there are good reasons why textbooks claim that you can't reach absolute zero. Of course if Heisenberg's uncertainty principle (and quantum mechanics) were not a true description of nature then you could do it, but there is absolutely no reason to think that Heisenberg's uncertainty principle is wrong and lots of reasons to think that it's right. You may as well try to build a pe <div class="Discussion_UserSignature"> </div>
 
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enigma10

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<blockquote><font class="small">In reply to:</font><hr /><p>If something is truly unobservable - meaning it can never have any effect on anything that humans could observe, then there is no way we could ever infer its existence. I don't know how you conclude that 90% of the universe is completely unobserveable; by definition we have no idea if there exists anything that is utterly unobservable. Note that this is different from dark matter or energy or what have you since those do have an observable effect on the universe which is how we infer their existence. Similarly there may exist many stars and exotic things in nature that we haven't observed yet, but we could one day hope to observe them. What I mean by things that are utterly unobservable are for example goblins that only interact with themselves via some 5th force but cannot interact with any of the matter/energy that we are made out of, or parallel universes that are completely off-limits to us - sure they may be out there, but we could never know. Similarly if there is something at exactly absolute zero temperature, then it can never interact with anything, meaning we can never even hope to know about it (let alone create it) - so it really is a pointless argument to debate whether or not there is such a system. <p><hr /></p></p></blockquote><br /> <br /> A small example would be black holes. Comparison. <br /><br />We know black holes exist, but we could never truly observe them or the system by which they operate, only thier effect.<br /><br /> Absolute zero. we know this to be the bottom of the scale in thermodynamics laws, but we can never directly observe it. Does this sound about right?<br /><br /> Now imagine , for the sake of theory, the forces so great at the center of a black hole that it literally super crunches an atom to a motionless form, the energy released in the process so powerfull, it literally escapes where nothing else can. This is all theoretical, of course, but could such a system exist? Would it be <div class="Discussion_UserSignature"> <em>"<font color="#333399">An organism at war with itself is a doomed organism." - Carl Sagan</font></em> </div>
 
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alokmohan

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You compre the concept with Goblin?If something is truly unobservable - meaning it can never have any effect on anything that humans could observe, then there is no way we could ever infer its existence. I don't know how you conclude that 90% of the universe is completely unobserveable; by definition we have no idea if there exists anything that is utterly unobservable. Note that this is different from dark matter or energy or what have you since those do have an observable effect on the universe which is how we infer their existence. Similarly there may exist many stars and exotic things in nature that we haven't observed yet, but we could one day hope to observe them. What I mean by things that are utterly unobservable are for example goblins that only interact with themselves via some 5th force but cannot interact with any of the matter/energy that we are made out of, or parallel universes that are completely off-limits to us - sure they may be out there, but we could never know. Similarly if there is something at exactly absolute zero temperature, then it can never interact with anything, meaning we can never even hope to know about it (let alone create it) - so it really is a pointless argument to debate whether or not there is such a system
 
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j_high211

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I did some research on Zeno's Paradox which states that to cover a distance from A to B, that object covering the distance must travel half the length from A to B than half that distance and half the distance after that resulting in the inability to ever reach point B because the length gets halfed into an infinitely small number.<br /><br />I think that this is a nice way to compare the concept of reaching absolute zero to. No matter how one trys to reach absolute zero, one must continue to drop the temperature by a fraction of the remainder to achieve absolute zero. With this stated, keep in mind that the colder something becomes, the more energy it takes to decrease that somethings temperature even more. This means that to reach absolute zero would require a monumental or possibly infinitely large amount of energy , which in turn yields the conclusion that absolute zero cannot and will not ever be reached regardless of how much energy we can use.<br /><br />Not only that, but how in the world would matter behave at absolute zero. If I'm thinking right, wouldn't that matter have absolutely no decay as well as no motion at all which would conflict with the laws of intermolecular forces.
 
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j_high211

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Did you take into consideration that something unobservable can be detected through the behavior of the systems around it. This method of discovering is how we detected Neptune's presence in the solar system before we could even see it. We studied it's effect on the planets and celestial objects around it. The same goes for black holes, dark matter, The core of stars, gravity, universal expansion, the curvature of the universe, etc.
 
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doubletruncation

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<font color="yellow">Did you take into consideration that something unobservable can be detected through the behavior of the systems around it. This method of discovering is how we detected Neptune's presence in the solar system before we could even see it. We studied it's effect on the planets and celestial objects around it. The same goes for black holes, dark matter, The core of stars, gravity, universal expansion, the curvature of the universe, etc.</font><br /><br />Right, so these are all things that interact in some way with matter that we can observe directly, so they have observational effects (e.g. they make the stars in galaxies orbit faster than you'd expect, or they cause Uranus to move across the sky in an unexpected manner) - that is why we can infer their existence. The point about a system exactly at absolute zero temperature was that it couldn't interact with anything, so it couldn't have any observational effects. The reason is that its energy would have to be defined with absolute precision for it to be at absolute zero temperature, but that means that the uncertainty in time for the system would have to be infinite (Heisenberg's uncertainty principle). If that system interacted with anything, in any way (even via gravity), ever, then it would have a finite uncertainty in time and hence could not have zero uncertainty in energy. This doesn't mean you can't get arbitrarily close to absolute zero (I think the point regarding Zeno's paradox is a good one). This is different from black holes, dark matter, or even dark energy for which you can infer their existence by their gravitational interaction with the rest of the world. <br /><br />If true absolute zero were ever actually obtained (how you would tell is a bit of a mystery to me since you couldn't interact with the material to measure its temperature), that would mean that quantum mechanics is wrong at some level. That's certainly possible, but I think it would be quite surprising <div class="Discussion_UserSignature"> </div>
 
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