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Note from micronesia: please read the thread before making comments about how we have just turned physics on its head. |
As a guy studying natural sciences at the university - this is pretty exciting. Just might write a paper about this if the source is reliable enough
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United Kingdom3482 Posts
On January 06 2013 23:55 See.Blue wrote:Show nested quote +On January 06 2013 00:08 IntoTheWow wrote:
I guess it depends on how you define temperature.
If you release these atoms from their arrangement, you would not get heat transfering to them, but from them. Exactly. Its a definitional game thats being played. It's neat, but nothing groundbreaking and the terminology/pop sci hype around it is outright misleading.
Well the definition is, in the technical sense, correct. It's the unscientific interpretation of scientific language where the the misleading comes in. Pop sci hype being misleading is certainly nothing new as it happens with basically every popularised discovery or theory.
edit: I definitely found the actual science interesting though. I have ended up learning a lot about how temperature is defined and some interesting stuff about thermodynamics that hasn't been covered in my degree so far.
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May I suggest that we burn the witch?
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United Kingdom3482 Posts
On January 07 2013 00:51 Djzapz wrote:
May I suggest that we burn the witch?
Well first we need to determine whether things at negative temperature float or sink.
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On January 06 2013 06:10 HunterX11 wrote:Show nested quote +On January 06 2013 03:26 Soulstice wrote:
Times like these when think back to when it was preposterous to think the earth was anything but flat. A year ago scientists would have clung on to the idea of absolute zero for dear life, now this. No Science is absolute! Was there really any time it was controversial to point out that the Earth is round, though?
Well, there was at least a time when the idea that it was round was thought to be in need of argument. Aristotle offers some convincing ones.
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On January 06 2013 15:16 imallinson wrote:Show nested quote +On January 06 2013 14:47 Chargelot wrote:On January 06 2013 13:14 GGTeMpLaR wrote:On January 05 2013 23:57 Fruscainte wrote:
For instance, Rosch and his colleagues have calculated that whereas clouds of atoms would normally be pulled downwards by gravity, if part of the cloud is at a negative absolute temperature, some atoms will move upwards, apparently defying gravity4.
Holy shit.. mass effect anyone? I have a question though. Since the energy moves from a parts of atoms in the cloud at negative-kelvin to the positive-kelvin atoms in the cloud (from cold to hot, the opposite of what is normal), would the negative-kelvin atoms just continue to get colder and colder with a higher and higher value of negative-kelvin? edit: Is negative-kelvin actually cold or is it hot? I'm reading negative-kelvin is actually hotter than any value of positive-kelvin since heat will always flow from negative to positive? Also, does this invalidate the second law of thermodynamics? Is it possible the conditions necessary to reach this negative-kelvin temperature could ever occur naturally in the cosmos? This occurs naturally in stars and black holes. Negative-kelvin is hotter than any positive-kelvin. That is: -1K > 100,000,000K Because energy will always flow from the negative system to the positive system. In this case, temperature is being described as T^(-1) = dS/dE meaning when you find the slope of the line that you get when you graph entropy vs energy, its inverse will be the temperature. I'm sure if you could hold something that was -100k in your hands, and something that was 100,000,000K in your hands, the -100k wouldn't feel nearly as "hot" as the other. But, the -100K would still donate energy to the 100,000,000K system, and therefore it has a higher temperature. But I suspect that -100K feels as hot as 100K. It's just the movement of energy which differs them for the most part. I'm certainly no expert at biology but if your hand could actually hold either of those things without melting and you could differentiate between two very high temperatures surely the -100K object would feel much hotter because your nerves are basically sensing the heat transfer which would be greater for the -100K object.
Allow me to restate
To a 0.01K system, a -100K system and a 100K system have the same energy to offer it, and independent of each other, the energy flow from a -100K system to a 0.01K system and the energy flow from a 100K system to a 0.01K system would be about the same, within reason. Would a 100K system actually feel hot in your hand? No, it'd fucking turn your hand to ice and your hand would fall off of your arm.
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I remember in chemistry class my teacher saying we have gotten close, but never absolute zero before. This is truly an amazing achievement. Who knows what this will lead to!
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On January 07 2013 02:24 Yergidy wrote:
I remember in chemistry class my teacher saying we have gotten close, but never absolute zero before. This is truly an amazing achievement. Who knows what this will lead to!
This is still true. The "temperature change" in the article is discontinuous and does not pass absolute zero.
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+ Show Spoiler +
On January 07 2013 02:17 Chargelot wrote:Show nested quote +On January 06 2013 15:16 imallinson wrote:On January 06 2013 14:47 Chargelot wrote:On January 06 2013 13:14 GGTeMpLaR wrote:On January 05 2013 23:57 Fruscainte wrote:
For instance, Rosch and his colleagues have calculated that whereas clouds of atoms would normally be pulled downwards by gravity, if part of the cloud is at a negative absolute temperature, some atoms will move upwards, apparently defying gravity4.
Holy shit.. mass effect anyone? I have a question though. Since the energy moves from a parts of atoms in the cloud at negative-kelvin to the positive-kelvin atoms in the cloud (from cold to hot, the opposite of what is normal), would the negative-kelvin atoms just continue to get colder and colder with a higher and higher value of negative-kelvin? edit: Is negative-kelvin actually cold or is it hot? I'm reading negative-kelvin is actually hotter than any value of positive-kelvin since heat will always flow from negative to positive? Also, does this invalidate the second law of thermodynamics? Is it possible the conditions necessary to reach this negative-kelvin temperature could ever occur naturally in the cosmos? This occurs naturally in stars and black holes. Negative-kelvin is hotter than any positive-kelvin. That is: -1K > 100,000,000K Because energy will always flow from the negative system to the positive system. In this case, temperature is being described as T^(-1) = dS/dE meaning when you find the slope of the line that you get when you graph entropy vs energy, its inverse will be the temperature. I'm sure if you could hold something that was -100k in your hands, and something that was 100,000,000K in your hands, the -100k wouldn't feel nearly as "hot" as the other. But, the -100K would still donate energy to the 100,000,000K system, and therefore it has a higher temperature. But I suspect that -100K feels as hot as 100K. It's just the movement of energy which differs them for the most part. I'm certainly no expert at biology but if your hand could actually hold either of those things without melting and you could differentiate between two very high temperatures surely the -100K object would feel much hotter because your nerves are basically sensing the heat transfer which would be greater for the -100K object. Allow me to restate To a 0.01K system, a -100K system and a 100K system have the same energy to offer it, and independent of each other, the energy flow from a -100K system to a 0.01K system and the energy flow from a 100K system to a 0.01K system would be about the same, within reason. Would a 100K system actually feel hot in your hand? No, it'd fucking turn your hand to ice and your hand would fall off of your arm.
Did you write that correctly or are you missing a - ?
Also, why are people saying it would be hot -_-
Would it be very hot or very cold ffs?
I need to pay more attention =(
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On January 07 2013 02:37 Reason wrote:Show nested quote +On January 07 2013 02:17 Chargelot wrote:On January 06 2013 15:16 imallinson wrote:On January 06 2013 14:47 Chargelot wrote:On January 06 2013 13:14 GGTeMpLaR wrote:On January 05 2013 23:57 Fruscainte wrote:
For instance, Rosch and his colleagues have calculated that whereas clouds of atoms would normally be pulled downwards by gravity, if part of the cloud is at a negative absolute temperature, some atoms will move upwards, apparently defying gravity4.
Holy shit.. mass effect anyone? I have a question though. Since the energy moves from a parts of atoms in the cloud at negative-kelvin to the positive-kelvin atoms in the cloud (from cold to hot, the opposite of what is normal), would the negative-kelvin atoms just continue to get colder and colder with a higher and higher value of negative-kelvin? edit: Is negative-kelvin actually cold or is it hot? I'm reading negative-kelvin is actually hotter than any value of positive-kelvin since heat will always flow from negative to positive? Also, does this invalidate the second law of thermodynamics? Is it possible the conditions necessary to reach this negative-kelvin temperature could ever occur naturally in the cosmos? This occurs naturally in stars and black holes. Negative-kelvin is hotter than any positive-kelvin. That is: -1K > 100,000,000K Because energy will always flow from the negative system to the positive system. In this case, temperature is being described as T^(-1) = dS/dE meaning when you find the slope of the line that you get when you graph entropy vs energy, its inverse will be the temperature. I'm sure if you could hold something that was -100k in your hands, and something that was 100,000,000K in your hands, the -100k wouldn't feel nearly as "hot" as the other. But, the -100K would still donate energy to the 100,000,000K system, and therefore it has a higher temperature. But I suspect that -100K feels as hot as 100K. It's just the movement of energy which differs them for the most part. I'm certainly no expert at biology but if your hand could actually hold either of those things without melting and you could differentiate between two very high temperatures surely the -100K object would feel much hotter because your nerves are basically sensing the heat transfer which would be greater for the -100K object. Allow me to restate To a 0.01K system, a -100K system and a 100K system have the same energy to offer it, and independent of each other, the energy flow from a -100K system to a 0.01K system and the energy flow from a 100K system to a 0.01K system would be about the same, within reason. Would a 100K system actually feel hot in your hand? No, it'd fucking turn your hand to ice and your hand would fall off of your arm. Did you write that correctly or are you missing a - ? Also, why are people saying it would be hot -_- Would it be very hot or very cold ffs?
When a system is putting out energy it will feel warm, when it's taking energy away, it will feel cold.
The negative system would be putting out energy to a system with 'more' energy, like your hand (which is way warmer than 100K) and the positive system would take energy away, because your hand would have more (the 100K itself is 'cold' and has less energy).
It's like... a kid who has a bunch of candy giving away some candy is regular positive temperatures, and a kid with one piece of candy giving it to the kid with lots is negative temperatures.
EDIT: This is really not a proper technical description, but I'm also not a physicist.
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Wait wait wait, my hand is warmer than 100k =/ ?
Don't make me read the whole thread again =(
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On January 07 2013 02:37 Reason wrote:Show nested quote +On January 07 2013 02:17 Chargelot wrote:On January 06 2013 15:16 imallinson wrote:On January 06 2013 14:47 Chargelot wrote:On January 06 2013 13:14 GGTeMpLaR wrote:On January 05 2013 23:57 Fruscainte wrote:
For instance, Rosch and his colleagues have calculated that whereas clouds of atoms would normally be pulled downwards by gravity, if part of the cloud is at a negative absolute temperature, some atoms will move upwards, apparently defying gravity4.
Holy shit.. mass effect anyone? I have a question though. Since the energy moves from a parts of atoms in the cloud at negative-kelvin to the positive-kelvin atoms in the cloud (from cold to hot, the opposite of what is normal), would the negative-kelvin atoms just continue to get colder and colder with a higher and higher value of negative-kelvin? edit: Is negative-kelvin actually cold or is it hot? I'm reading negative-kelvin is actually hotter than any value of positive-kelvin since heat will always flow from negative to positive? Also, does this invalidate the second law of thermodynamics? Is it possible the conditions necessary to reach this negative-kelvin temperature could ever occur naturally in the cosmos? This occurs naturally in stars and black holes. Negative-kelvin is hotter than any positive-kelvin. That is: -1K > 100,000,000K Because energy will always flow from the negative system to the positive system. In this case, temperature is being described as T^(-1) = dS/dE meaning when you find the slope of the line that you get when you graph entropy vs energy, its inverse will be the temperature. I'm sure if you could hold something that was -100k in your hands, and something that was 100,000,000K in your hands, the -100k wouldn't feel nearly as "hot" as the other. But, the -100K would still donate energy to the 100,000,000K system, and therefore it has a higher temperature. But I suspect that -100K feels as hot as 100K. It's just the movement of energy which differs them for the most part. I'm certainly no expert at biology but if your hand could actually hold either of those things without melting and you could differentiate between two very high temperatures surely the -100K object would feel much hotter because your nerves are basically sensing the heat transfer which would be greater for the -100K object. Allow me to restate To a 0.01K system, a -100K system and a 100K system have the same energy to offer it, and independent of each other, the energy flow from a -100K system to a 0.01K system and the energy flow from a 100K system to a 0.01K system would be about the same, within reason. Would a 100K system actually feel hot in your hand? No, it'd fucking turn your hand to ice and your hand would fall off of your arm. Did you write that correctly or are you missing a - ? Also, why are people saying it would be hot -_- Would it be very hot or very cold ffs?
-100K would feel warm, maybe even hot.
-1000K would be like sticking your hand into a blue flame.
+100K would be so cold it would kill whatever part of you touched it.
+1000K would be like sticking your hand into a blue flame.
On January 07 2013 02:58 Reason wrote:
Wait wait wait, my hand is warmer than 100k =/ ?
Don't make me read the whole thread again =(
100K is about -173C or -279F. It's really really cold.
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On January 07 2013 02:58 Chargelot wrote:Show nested quote +On January 07 2013 02:37 Reason wrote:On January 07 2013 02:17 Chargelot wrote:On January 06 2013 15:16 imallinson wrote:On January 06 2013 14:47 Chargelot wrote:On January 06 2013 13:14 GGTeMpLaR wrote:On January 05 2013 23:57 Fruscainte wrote:
For instance, Rosch and his colleagues have calculated that whereas clouds of atoms would normally be pulled downwards by gravity, if part of the cloud is at a negative absolute temperature, some atoms will move upwards, apparently defying gravity4.
Holy shit.. mass effect anyone? I have a question though. Since the energy moves from a parts of atoms in the cloud at negative-kelvin to the positive-kelvin atoms in the cloud (from cold to hot, the opposite of what is normal), would the negative-kelvin atoms just continue to get colder and colder with a higher and higher value of negative-kelvin? edit: Is negative-kelvin actually cold or is it hot? I'm reading negative-kelvin is actually hotter than any value of positive-kelvin since heat will always flow from negative to positive? Also, does this invalidate the second law of thermodynamics? Is it possible the conditions necessary to reach this negative-kelvin temperature could ever occur naturally in the cosmos? This occurs naturally in stars and black holes. Negative-kelvin is hotter than any positive-kelvin. That is: -1K > 100,000,000K Because energy will always flow from the negative system to the positive system. In this case, temperature is being described as T^(-1) = dS/dE meaning when you find the slope of the line that you get when you graph entropy vs energy, its inverse will be the temperature. I'm sure if you could hold something that was -100k in your hands, and something that was 100,000,000K in your hands, the -100k wouldn't feel nearly as "hot" as the other. But, the -100K would still donate energy to the 100,000,000K system, and therefore it has a higher temperature. But I suspect that -100K feels as hot as 100K. It's just the movement of energy which differs them for the most part. I'm certainly no expert at biology but if your hand could actually hold either of those things without melting and you could differentiate between two very high temperatures surely the -100K object would feel much hotter because your nerves are basically sensing the heat transfer which would be greater for the -100K object. Allow me to restate To a 0.01K system, a -100K system and a 100K system have the same energy to offer it, and independent of each other, the energy flow from a -100K system to a 0.01K system and the energy flow from a 100K system to a 0.01K system would be about the same, within reason. Would a 100K system actually feel hot in your hand? No, it'd fucking turn your hand to ice and your hand would fall off of your arm. Did you write that correctly or are you missing a - ? Also, why are people saying it would be hot -_- Would it be very hot or very cold ffs? -100K would feel warm, maybe even hot. -1000K would be like sticking your hand into a blue flame. +100K would be so cold it would kill whatever part of you touched it. +1000K would be like sticking your hand into a blue flame. Show nested quote +On January 07 2013 02:58 Reason wrote:
Wait wait wait, my hand is warmer than 100k =/ ?
Don't make me read the whole thread again =( 100K is about -173C or -279F. It's really really cold.
Okay that makes sense.
It REALLY doesn't help using a number system where positive values are actually temperatures below and above zero -_-
When you said this
"To a 0.01K system, a -100K system and a 100K system have the same energy to offer it, and independent of each other, the energy flow from a -100K system to a 0.01K system"
It seems like you're referring to three systems, one above and one below absolute zero, and one as close as we can possibly get... that's what I thought you meant. Sorry that's just my own ignorance I guess but still confusing imo.
I think actually if you had written what you'd said as -100o, 0.01o and 100o (celsius) you maybe could have made the point clearer?
At least I would have understood lol -_- thanks for explaining anyway.
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On January 07 2013 02:59 Reason wrote:Show nested quote +On January 07 2013 02:58 Chargelot wrote:On January 07 2013 02:37 Reason wrote:On January 07 2013 02:17 Chargelot wrote:On January 06 2013 15:16 imallinson wrote:On January 06 2013 14:47 Chargelot wrote:On January 06 2013 13:14 GGTeMpLaR wrote:On January 05 2013 23:57 Fruscainte wrote:
For instance, Rosch and his colleagues have calculated that whereas clouds of atoms would normally be pulled downwards by gravity, if part of the cloud is at a negative absolute temperature, some atoms will move upwards, apparently defying gravity4.
Holy shit.. mass effect anyone? I have a question though. Since the energy moves from a parts of atoms in the cloud at negative-kelvin to the positive-kelvin atoms in the cloud (from cold to hot, the opposite of what is normal), would the negative-kelvin atoms just continue to get colder and colder with a higher and higher value of negative-kelvin? edit: Is negative-kelvin actually cold or is it hot? I'm reading negative-kelvin is actually hotter than any value of positive-kelvin since heat will always flow from negative to positive? Also, does this invalidate the second law of thermodynamics? Is it possible the conditions necessary to reach this negative-kelvin temperature could ever occur naturally in the cosmos? This occurs naturally in stars and black holes. Negative-kelvin is hotter than any positive-kelvin. That is: -1K > 100,000,000K Because energy will always flow from the negative system to the positive system. In this case, temperature is being described as T^(-1) = dS/dE meaning when you find the slope of the line that you get when you graph entropy vs energy, its inverse will be the temperature. I'm sure if you could hold something that was -100k in your hands, and something that was 100,000,000K in your hands, the -100k wouldn't feel nearly as "hot" as the other. But, the -100K would still donate energy to the 100,000,000K system, and therefore it has a higher temperature. But I suspect that -100K feels as hot as 100K. It's just the movement of energy which differs them for the most part. I'm certainly no expert at biology but if your hand could actually hold either of those things without melting and you could differentiate between two very high temperatures surely the -100K object would feel much hotter because your nerves are basically sensing the heat transfer which would be greater for the -100K object. Allow me to restate To a 0.01K system, a -100K system and a 100K system have the same energy to offer it, and independent of each other, the energy flow from a -100K system to a 0.01K system and the energy flow from a 100K system to a 0.01K system would be about the same, within reason. Would a 100K system actually feel hot in your hand? No, it'd fucking turn your hand to ice and your hand would fall off of your arm. Did you write that correctly or are you missing a - ? Also, why are people saying it would be hot -_- Would it be very hot or very cold ffs? -100K would feel warm, maybe even hot. -1000K would be like sticking your hand into a blue flame. +100K would be so cold it would kill whatever part of you touched it. +1000K would be like sticking your hand into a blue flame. On January 07 2013 02:58 Reason wrote:
Wait wait wait, my hand is warmer than 100k =/ ?
Don't make me read the whole thread again =( 100K is about -173C or -279F. It's really really cold. Okay that makes sense. It REALLY doesn't help using a number system where positive values are actually temperatures below and above zero -_- When you said this "To a 0.01K system, a -100K system and a 100K system have the same energy to offer it, and independent of each other, the energy flow from a -100K system to a 0.01K system" It seems like you're referring to three systems, one above and one below absolute zero, and one as close as we can possibly get... that's what I thought you meant. Sorry that's just my own ignorance I guess but still confusing imo. I think actually if you had written what you'd said as -100o, 0.01o and 100o (celsius) you maybe could have made the point clearer? At least I would have understood lol -_- thanks for explaining anyway.
Btw, do you use C or F in United Kingdom ?
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Negative numbers in this sense really aren't usable on the traditional number line.
-1...0...+1 is good for just about all other applications. But for negative temperature (in terms of kelvins) it is closer to:
0...+1...+∞...-1...-∞. It's almost like two number lines grow out of zero in the same direction (Hopefully this is a good description). But describing how they'd feel in your hand was a unique challenge, because negative temperatures are describing energy/entropy states, not how they actually feel to us.
In terms of the actual energy there, I think an X Kelvin system has the same energy as a -X kelvin system. Below body temperature (310K) the positive system would feel cold, while the negative system would feel hot. Above 310K, all systems would feel warm/hot.
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On January 06 2013 08:51 lightrise wrote:Show nested quote +On January 06 2013 02:59 Evangelist wrote:On January 06 2013 01:13 micronesia wrote:
I want to point out that saying entropy is the disorder of a system is about as accurate as saying temperature is the speed of molecules in a system. Thermal physics is difficult to discuss without studying it. No, entropy is pretty much the disorder in a system when you define order as having structure. That's about all you really need to know at the quantum mechanical level, certainly enough to understand how this works. What is your expertise to comment on the issue btw. I am curious because you have no correct both micronesia and myself and a graduate level physicist. I am a senior in chemical engineering and have studied this stuff in Physical chemistry and other classes and it still doesn't make that much sense.
I'm a PhD plasma physicist working in the field of laser induced plasmas. As far as I'm concerned, that definition of entropy holds for all but the most theoretical of works - which this isn't.
To state it in a manner more defined than that is to lose the purpose of my posts here which is to explain this to the layman. I'm not really here to impress anyone with my understanding, just to help people understand the significance of something that was achieved in a field not so far removed from mine and furthermore justify my future funding :p
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Could we even feel negative temperature? I doubt our skin had much time to evolve a feeling process for this.
Just throwing this question in here, because it´s really hard to understand why it feels the same way with +300K and -300K :/
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Btw, do you use C or F in United Kingdom ?
We use C
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so if I get this right, they have enhanced a gas so that its atoms can shift from low to high energy states, making it possible for these atoms to move at 0K, and therefore creating the possibility of the temperature to get colder than 0K?
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EPT
