The same way they'll reach the speed of light: they won't.
Scientists have gotten to 2 degrees kelvin
It's 2 Kelvin (no degrees) and scientists have gotten a whole hell of a lot closer to absolute zero than 2 Kelvin. The lowest man-made temperature I know of is 450 picokelvin set by a team of scientists at MIT.
That's 0.00000000045 K, which is decidedly closer to 0 than 2.
The same way they'll reach the speed of light: they won't.
It's 2 Kelvin (no degrees) and scientists have gotten a whole hell of a lot closer to absolute zero than 2 Kelvin. The lowest man-made temperature I know of is 450 picokelvin set by a team of scientists at MIT.
That's 0.00000000045 K, which is decidedly closer to 0 than 2.
I'm sorry, I was just thinking about this randomly, and I heard that they reached 2 Kelvin so...
I thought I read somewhere that they got to some temperature below absolute 0 by some freaky physics and a strict legal-like definition of the term "temperature." Don't quote me on that though 'cause I don't remember where I saw it (probably the XKCD forums, they're always posting odd science news tidbits).
I thought I read somewhere that they got to some temperature below absolute 0 by some freaky physics and a strict legal-like definition of the term "temperature." Don't quote me on that though 'cause I don't remember where I saw it (probably the XKCD forums, they're always posting odd science news tidbits).
Temperature expresses a relationship between the energy of a system and its entropy. The definition goes like this:
1/T = dS/dE
In English, that basically says that the reciprocal of the temperature is equal to the rate of change of entropy with respect to energy.
Qualitatively this means a few things. Most systems we're familiar with exhibit the property that adding energy to the system increases its entropy, so dS/dE is positive and then so is temperature.
The thing is, though, we can create systems (usually quantum mechanical in nature) where adding energy actually reduces the entropy of the system (this typically happens because there's fewer quantum states at higher energy levels in these systems, so when you add energy, you force the system into fewer states, which decreases its entropy). Since the entropy decreases with increasing energy, dS/dE is negative and then so is temperature.
That is a negative temperature system. The trick is, though, this temperature really only applies to a small part of a system that has been isolated to keep it from exchanging energy with other things. These systems are also peculiar in the sense that they can reach a technically infinite temperature as well.
What happens in that case is that the temperature starts out positive because at low enough energy states, increases in energy increase the entropy. However, because there's a point of maximum entropy as you add energy after which entropy decreases, what will happen as you add energy is the temperature will increase to infinity, then wrap around through negative infinity and start approaching absolute 0 from below.
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Never attribute to malice what can adequately be explained by incompetence.
I thought I read somewhere that they got to some temperature below absolute 0 by some freaky physics and a strict legal-like definition of the term "temperature." Don't quote me on that though 'cause I don't remember where I saw it (probably the XKCD forums, they're always posting odd science news tidbits).
Absolute Zero is the lowest possible temperature, where all atoms are at their lowest possible energy state. How can you have anything less than the least. And I personally think we'll never reach absolute zero. Pretty sure CentrallyProcessed got it right, it's impossible.
Absolute Zero is the lowest possible temperature, where all atoms are at their lowest possible energy state. How can you have anything less than the least. And I personally think we'll never reach absolute zero. Pretty sure CentrallyProcessed got it right, it's impossible.
Surprise, two posts above yours explains exactly how it's technically possible: A strict, legal like definition of temperature and some freaky physics. Not only is it technically possible, it's already happened.
Quantum Mechanics is weird. It takes things the average person deems impossible and makes them possible, albeit on really small scales.
Temperature expresses a relationship between the energy of a system and its entropy. The definition goes like this:
1/T = dS/dE
In English, that basically says that the reciprocal of the temperature is equal to the rate of change of entropy with respect to energy.
Qualitatively this means a few things. Most systems we're familiar with exhibit the property that adding energy to the system increases its entropy, so dS/dE is positive and then so is temperature.
The thing is, though, we can create systems (usually quantum mechanical in nature) where adding energy actually reduces the entropy of the system (this typically happens because there's fewer quantum states at higher energy levels in these systems, so when you add energy, you force the system into fewer states, which decreases its entropy). Since the entropy decreases with increasing energy, dS/dE is negative and then so is temperature.
That is a negative temperature system. The trick is, though, this temperature really only applies to a small part of a system that has been isolated to keep it from exchanging energy with other things. These systems are also peculiar in the sense that they can reach a technically infinite temperature as well.
What happens in that case is that the temperature starts out positive because at low enough energy states, increases in energy increase the entropy. However, because there's a point of maximum entropy as you add energy after which entropy decreases, what will happen as you add energy is the temperature will increase to infinity, then wrap around through negative infinity and start approaching absolute 0 from below.
Systems with negative temperatures always transfer energy to systems with positive temperatures. In this way it can be said that negative temperatures are hotter than positive temperatures.
If you are a Battletech/Mechwarrior geek you may enjoy my Timberwolf/MADCAT model (the source of my avatar) (warning: image-heavy link target) I will often edit my posts after I have posted them in an attempt to improve their clarity (I value a few high quality posts over several low quality ones; the more lengthy the post, the more time it requires to edit) so you might want to wait for a while if this post is recent and refresh to see if anything has changed before replying to it.
It's 2 Kelvin (no degrees) and scientists have gotten a whole hell of a lot closer to absolute zero than 2 Kelvin. The lowest man-made temperature I know of is 450 picokelvin set by a team of scientists at MIT.
That's 0.00000000045 K, which is decidedly closer to 0 than 2.
Temperature expresses a relationship between the energy of a system and its entropy. The definition goes like this:
1/T = dS/dE
In English, that basically says that the reciprocal of the temperature is equal to the rate of change of entropy with respect to energy.
Qualitatively this means a few things. Most systems we're familiar with exhibit the property that adding energy to the system increases its entropy, so dS/dE is positive and then so is temperature.
The thing is, though, we can create systems (usually quantum mechanical in nature) where adding energy actually reduces the entropy of the system (this typically happens because there's fewer quantum states at higher energy levels in these systems, so when you add energy, you force the system into fewer states, which decreases its entropy). Since the entropy decreases with increasing energy, dS/dE is negative and then so is temperature.
That is a negative temperature system. The trick is, though, this temperature really only applies to a small part of a system that has been isolated to keep it from exchanging energy with other things. These systems are also peculiar in the sense that they can reach a technically infinite temperature as well.
What happens in that case is that the temperature starts out positive because at low enough energy states, increases in energy increase the entropy. However, because there's a point of maximum entropy as you add energy after which entropy decreases, what will happen as you add energy is the temperature will increase to infinity, then wrap around through negative infinity and start approaching absolute 0 from below.
Absolute Zero is the lowest possible temperature, where all atoms are at their lowest possible energy state. How can you have anything less than the least. And I personally think we'll never reach absolute zero. Pretty sure CentrallyProcessed got it right, it's impossible.
impossible.
Surprise, two posts above yours explains exactly how it's technically possible: A strict, legal like definition of temperature and some freaky physics. Not only is it technically possible, it's already happened.
Quantum Mechanics is weird. It takes things the average person deems impossible and makes them possible, albeit on really small scales.
Edit: Found the thread where they talk about it: http://forums.xkcd.com/viewtopic.php?f=9&t=99519
This means that you can approach 0K, but never actually achieve it.
Systems with negative temperatures always transfer energy to systems with positive temperatures. In this way it can be said that negative temperatures are hotter than positive temperatures.
A related video: Negative Temperatures are HOT
I will often edit my posts after I have posted them in an attempt to improve their clarity (I value a few high quality posts over several low quality ones; the more lengthy the post, the more time it requires to edit) so you might want to wait for a while if this post is recent and refresh to see if anything has changed before replying to it.
Nope.
http://en.wikipedia.org/wiki/Laser_cooling