Why would you think this would cheapen the kid's plight? Telling him he can't do something with kids his age because of a disability and that he should put his life on hold until something with a time-to-market of 20 years shows up?
Yes, sarcasm. With all due respect, I understand your position, but it's a cop-out answer.
But did I say he should put his life on hold? No, I simply said he should concentrate on what he can do. When technology adds map-reading to that set, he can do it.
There are certain things kids with disabilities can't do, obviously. A kid with paralysis of the lower body can't run track. But the point is to show these kids what they can do, not what they can't.He may not be able to run track, but if he wants to be near the sport, there are plenty of wheelchair track clubs he can participate in.
This sounds suspiciously like what I said. If technology can help him to some degree, then great. If the technology hasn't been developed yet, looks like he'll have to wait.
It's worth noting that social studies probably isn't an 'elective' for him in junior high.
Probably not. But are they really going to give him a hard time for doing poorly in areas of the subject that really heavily on vision he doesn't have? Is the american education system really that bad?
Most people in the US can see just fine and know jack squat about geography anyway.
True. Not to cheapen the kid's plight, but I reckon he ought to concentrate on what he can do with limited vision, and leave subjects like geography until decent prosthetic visual aids (ie implants) are developed (which should be well within his lifetime, given that they have had some success already.)
Didn't Tesla predict infinite bandwidth in the wireless spectrum by combining frequencies in certain combinations?..
Isn't the range of frequencies available for combination itself the bandwidth? Wider band of frequencies => sharper pulses can be formed by fourier synthesis => more 1s and 0s transmitted in a given time-frame?
But isn't that the question? Pasteurization - definitely good. Polio vaccination - definitely good. Separation of church and state - hell that's another debate but I think it's good.
I wouldn't necsessarily say that vaccinations are *definitely* a good thing (medicine -> less death -> overpopulation). Whether or not something is good depends on your own values. What is the good end we should be heading towards? Would the world be better if we had 6 billion people of varying degrees of happiness, or 6 million perfectly happy people?
What's best for the environment? Should we try and maintain it as it was before we evolved? Or how it would be now had we not existed? Or even how it would be if we had only developed the barest minimum of technology to sustain ourselves, and if so what is that limit? Should we preserve from extinction animals that are being wiped out by natural selection, or only those that we are contributing to the extinction of? And how do we *know* what's related to our activities and what's not?
These kinds of questions are my main problem with the 'green' or environmental movement. Exactly what are their goals? What would be an acceptable state to keep the earth in? If I thought that they even considered these questions, let alone had answers to them, I might be more supportive of them.
Re:Another 50 years of HEP...
on
Happy 50th Cern!
·
· Score: 3, Informative
They may remain strict and intellectually elegant, like chess, and bear no relation to reality whatsoever. Not to mention that very few even come close to the beauty of classic (that is non-relativistic) quantum theory. In addition it seems that the approach to math involved is quite liberal, the habit that Dirac started with his delta, but that later was taken to some new heights...
:)
What was Dirac's quote about aiming for mathematical elegance above other things again? I can't seem to find it at the moment. Sure classical QM was alot more elegant, but if it doesn't account for relativity, then it's simply not representative of reality, there's not much we can do about it.
Anyway, what I was trying to say is: in general, people still think of relativity as being completely theoretical. They don't realise that time dilation and such are phenomena that have been observed to occur so many times that there is simply no debate (as far as I know). The ideas of fission and fusion are pretty widespread in society, but very few people outside of geek circles are aware of the wavelike nature of particles. It's been known for almost 100 years, but it's like trying to explain it to people is just too hard, and so noone really bothers. Also, I think people perceive nuclear power as being the height of microscopic knowledge, when really, if you look at the understanding of nuclear forces at the time the bomb was developed (before Yukawa's model etc), it's actually kinda scary how little they knew. But the concepts are just too hard to get across in the infinitesimal attention span of your average joe, apparently. Anyway, your original assertion was that not alot of progress has been made since the adoption of QM, and I have to disagree, but add that most people not knowing about any of it isn't surprising, given that almost noone knows what the Bohr model was all about. But then I suspect you just have a very dim view of the real value of QED and the later, more fanciful theories. You may be right, and I don't think I can help there.:)
(I did make it small p unlike capital P later on, didn't I?)
Ever heard about Lorentz vectors? (E, px, py, pz) with "funny" (1, -1, -1, -1) metric (flat space diagonal) meaning when you multiply them, or square in our case, it expands to E^2 - px^2 - py^2 - pz^2
Ooops! Sorry. Writing math in ascii can be confusing (for me:) ). That and I don't assume quantities to be 4-vectors unless otherwise specified. (But in this context, I certainly should have. What a dummy.)
Over in the sense that all that's left are questions like 'What is energy?'
Just like the future of physics since 1894 lay in the seventh decimal place.
Yes, but I did say it all COULD be over in 50 years. I'm not going to make a solid assertion that we're nearing the end, like Maxwell did. However, I don't believe it would be a shock if we had a theory of everything within that time frame. Certainly if the LHC confirms the existence of the Higgs boson(s), and finds evidence of supersymmetry within the next 10 years, we could be looking at that outcome.
Re:Another 50 years of HEP...
on
Happy 50th Cern!
·
· Score: 4, Insightful
it will never be over.
the more we learn about nature, the more opportunities for speculation open up.
No, the more we learn about nature, the closer we come to the truth, which may or may not be open ended. Asserting that it will never be over assumes more knowledge than any of us have.
I may be wrong on that but it certainly seems that particle physics didn't really make any progress since quantum theory was accepted in.. what?.. early on in 20th century? If there's any "deeper understanding" gained since it certainly didn't make it into the wild yet...
Given that in this day and age that popular media still represent the electrons in an atom following exact orbits in the fashion of newtonian mechanics
is a pretty good indication that very little of modern physics has made it 'into the wild'.
And with the LHC in development, here's hoping for another 50!
With the LHC in development, it could be all over within another 50 years. (Over in the sense that all that's left are questions like 'What is energy?')
Stop smoking - caffeine and cigarettes often go together.
Actually, the human body metabolizes caffeine at about twice the rate in the presence of nicotine. So if you quit smoking, you should cut your caffeine consumption in half at the same time.
Radiation is not nearly as efficient as conductiion hence the need for so many fins on a heat sink. So I still think it would overheat extremely fast.
I think you'll find that the fins are to increase surface area for the purposes of convection. Convection of course dominates radiative transfers in a fluid like air.
As for radiative cooling in space, a quick ball park calculation is quite educational:
Objects emit radiation depending on their temperature, according to Stefan's law. They also absorb radiation from their surroundings according to the same equation, hence we can express the following formula for net power emitted as
P_net = {sigma}*A*e*(T^4 - T_0^4)
Here {sigma} is the stefan-boltzmann constant, 5.67e-8 W/(M^2*K^4), A the surface area of the object. T is the temperature of the object, and T_0 that of the background. e is the emissivity of the object, which we will assume to be 1 (perfect blackbody).
I saw a photo of the thermometer displaying -46 deg C(=227 K), and standard Pentium 4 3GHz apparently consume about 80 watts of power. We'll therefore assume that the madly overclocked P4 produces 200W of heat. The question is then, what area of radiator is required to maintain the chip's temperature, given that the temperature of deep space is about 3K (cosmic background radiation)?
An area of 1.3 m^2 corresponds to a sphere of radius 30cm. Conclusion: Put the chip in good thermal contact with a well-emitting sphere big enough to contain the chip and motherboard, and it'll probably be fine.
Actually no, It would overheat quite quickly as a vaccuum is a very good insulator (heh some would say almost perfect).
Aside from RADIATIVE heat exchange of course. Dewar flasks use a vacuum gap for insulation, but the glass is coated with a highly reflective (and hence poorly emissive) metallic film. Paint the damn thing black, and it'll bleed plenty of heat off into the 2.7K hell that is space.
Ha, no, they recently got fermionic atoms to form a BEC.;)
I know, it's a trick. The fermionic atoms pair up. Weird trick, I don't really get it. (How are they overlapping enough do that in the first place? Damn quantum mechanics.)
Thanks for the cool link! They overlap because the de Broglie wavelength of the particle is inversely proportional to its momentum, and the particle can't be located to any more accuracy than its wavelength, hence at low temperatures the atoms are spread all over the place. This is also how the BCS theory explains superconductivity (pairing of electrons in that case), but I guess you probably know that;)
Also of relevant (to this thread, not the story) interest is that during the formation of a neutron
star, there is a period during which the iron atoms of the stellar core pair up and hence exhibit superfluid behaviour, before their electrons are crushed into their nuclei.(not that I've ever met a forming neutron star, of course;) )
A windfarm is [multiple] big steel poles with turbines and big steel blades on top. How is that 'heavy industrial work'? It's much less 'heavy' than building a few houses, for example.
What part of building [multiple] big steel poles doesn't consume loads of energy? Is it the mining of the iron ore? The furnaces? And what part of digging big holes in the ground with smog-belching machinery and filling them with concrete (so the windmills don't, you know, blow over in the wind) doesn't?
But I thought it was simply a matter of temperature...it was just we don't have any way to get them down that low if they keep bouncing off each other.
I could be wrong, but I think that many-body interactions can change the internal states of the atoms, which of course must be the same across the board for the condensate to form.
In a nutshell, BECs are formed by applying a magnetic field, which is essentially a 3D SHO potential (mass on a spring). The atoms are cooled by lasers, craftily 'detuned' from the resonant frequency of the atoms, so that, due to the Doppler effect, atoms approaching the laser experience a retarding force, while atoms receding from the laser experience very little force. In this manner the gas sample can be cooled to ~1 microKelvin (?), which is still far too warm for condensation to occur.
The magnetic field is then manipulated to form a 'cup' which holds the atoms. The walls of the 'cup' are gently rolled back, so that the most energetic of the atoms 'boil off' the top, taking excess energy & entropy with them (evaporative cooling), and the remaining atoms rethermalize at a lower temperature.
Once a significant number of atoms fall into the ground state of the SHO, the rest quickly follow, as the probability of scattering into a given state greatly increases with the number of atoms in that state. (this is entirely analogous to photons in a laser all precipitating into the same state, for the same reasons, forming a coherent beam. And it only occurs for atoms which are bosonic, ie those for which #p + #n + #e = even)
Why couldn't we use Wind-power to extract Hydrogen from water? That seems like an infinite supply of hydrogen right there...
Because a)not a lot of people honestly fancy having a windmill farm in their backyard, b) there is only a finite area on which we can build them, and c)it takes alot of heavy construction work to build them, which pollutes the environment, and it therefore takes a while for the things to pay for themselves ecologically.
Don't get me wrong, this still reduces our dependence on oil, and will be a huge help to city pollution, but I think we need to quickly figure out some way to make hydrogen cheaply and cleanly. Maybe nuclear powered hydrogen production plants? Just thinking...
I'm inclined to agree with you. Electric cars and such are pointless (from an environmental perspective), if you have to charge them from a wall socket which is powered by a coal power station (or a fission reactor, until such time as we figure out WTF to do with the waste), especially considering the massive inefficiencies between the station and the socket.
These new technologies need to be developed with an eye on the ultimate goal of efficiently distributing and storing energy produced in clean fusion power stations, when such stations are realised. Otherwise it's only going to help the oil cartels retain market share when we stop using oil, and kid some naive people into thinking they're helping things.
But assuming you mean 'near 0 Kelvin', like d00ket pointed out, things get really weird down there. Some substances don't appear to have freezing points, there is no state below 'liquid'...they just move slower and slower. And some freeze quite normally, then do another transition way down there where they move back to a liquid like substance.
It should be noted, in the case of Bose Einstein Condensates, that it isn't simply a matter of temperature. BECs are formed by cooling a gas sample (with lasers, believe it or not) at extremely low pressure. This is because the transition must occur directly from the gaseous phase to the condensate phase. A low pressure ensures that collisions between the atoms are rare, and that most all collisions occur between 2 atoms. Interactions between 3 or more atoms lead to the liquid and solid phases of the element at those temperatures, and preclude the formation of the condensate.
At precisely absolute zero, everything is solid. Movement even on the atomic level requires kinetic energy; the presence of kinetic energy means the temperature is a tiny fraction above absolute zero.
Absolute zero would correspond to a complete absence of movement, which is impossible. This can be seen as a consequence of a few features of quantum mechanics. One of the most intuitive ways to show it (IMHO) is as follows:
The Heisenberg Uncertainty Principle states that the product of the uncertainty in position and the uncertainty in momentum of a particle is greater than a small constant.
A motionless particle would have a completely certain velocity (zero), and a constant position. Hence both uncertainties would be zero, and their product would therefore be zero, and not greater than h-bar/2. Therefore motionless particles are prohibited, and absolute zero is unattainable.
Slashdot Mirror
Why would you think this would cheapen the kid's plight? Telling him he can't do something with kids his age because of a disability and that he should put his life on hold until something with a time-to-market of 20 years shows up? Yes, sarcasm. With all due respect, I understand your position, but it's a cop-out answer.
But did I say he should put his life on hold? No, I simply said he should concentrate on what he can do. When technology adds map-reading to that set, he can do it.
There are certain things kids with disabilities can't do, obviously. A kid with paralysis of the lower body can't run track. But the point is to show these kids what they can do, not what they can't.He may not be able to run track, but if he wants to be near the sport, there are plenty of wheelchair track clubs he can participate in.
This sounds suspiciously like what I said. If technology can help him to some degree, then great. If the technology hasn't been developed yet, looks like he'll have to wait.
It's worth noting that social studies probably isn't an 'elective' for him in junior high.
Probably not. But are they really going to give him a hard time for doing poorly in areas of the subject that really heavily on vision he doesn't have? Is the american education system really that bad?
Most people in the US can see just fine and know jack squat about geography anyway.
True. Not to cheapen the kid's plight, but I reckon he ought to concentrate on what he can do with limited vision, and leave subjects like geography until decent prosthetic visual aids (ie implants) are developed (which should be well within his lifetime, given that they have had some success already.)
It wouldn't be hard at all to code up something that just generated 20 500mb files of random bytes.....
But could you do it ten times?
Didn't Tesla predict infinite bandwidth in the wireless spectrum by combining frequencies in certain combinations? ..
Isn't the range of frequencies available for combination itself the bandwidth?
Wider band of frequencies => sharper pulses can be formed by fourier synthesis => more 1s and 0s transmitted in a given time-frame?
Seymour Skinner: Parent that waives the right to sue says 'what'?
But isn't that the question? Pasteurization - definitely good. Polio vaccination - definitely good. Separation of church and state - hell that's another debate but I think it's good.
I wouldn't necsessarily say that vaccinations are *definitely* a good thing (medicine -> less death -> overpopulation). Whether or not something is good depends on your own values. What is the good end we should be heading towards? Would the world be better if we had 6 billion people of varying degrees of happiness, or 6 million perfectly happy people?
What's best for the environment? Should we try and maintain it as it was before we evolved? Or how it would be now had we not existed? Or even how it would be if we had only developed the barest minimum of technology to sustain ourselves, and if so what is that limit? Should we preserve from extinction animals that are being wiped out by natural selection, or only those that we are contributing to the extinction of? And how do we *know* what's related to our activities and what's not?
These kinds of questions are my main problem with the 'green' or environmental movement. Exactly what are their goals? What would be an acceptable state to keep the earth in? If I thought that they even considered these questions, let alone had answers to them, I might be more supportive of them.
They may remain strict and intellectually elegant, like chess, and bear no relation to reality whatsoever. Not to mention that very few even come close to the beauty of classic (that is non-relativistic) quantum theory. In addition it seems that the approach to math involved is quite liberal, the habit that Dirac started with his delta, but that later was taken to some new heights...
:)
What was Dirac's quote about aiming for mathematical elegance above other things again? I can't seem to find it at the moment. Sure classical QM was alot more elegant, but if it doesn't account for relativity, then it's simply not representative of reality, there's not much we can do about it.
:)
Anyway, what I was trying to say is:
in general, people still think of relativity as being completely theoretical. They don't realise that time dilation and such are phenomena that have been observed to occur so many times that there is simply no debate (as far as I know). The ideas of fission and fusion are pretty widespread in society, but very few people outside of geek circles are aware of the wavelike nature of particles. It's been known for almost 100 years, but it's like trying to explain it to people is just too hard, and so noone really bothers. Also, I think people perceive nuclear power as being the height of microscopic knowledge, when really, if you look at the understanding of nuclear forces at the time the bomb was developed (before Yukawa's model etc), it's actually kinda scary how little they knew. But the concepts are just too hard to get across in the infinitesimal attention span of your average joe, apparently. Anyway, your original assertion was that not alot of progress has been made since the adoption of QM, and I have to disagree, but add that most people not knowing about any of it isn't surprising, given that almost noone knows what the Bohr model was all about. But then I suspect you just have a very dim view of the real value of QED and the later, more fanciful theories. You may be right, and I don't think I can help there.
(I did make it small p unlike capital P later on, didn't I?) Ever heard about Lorentz vectors? (E, px, py, pz) with "funny" (1, -1, -1, -1) metric (flat space diagonal) meaning when you multiply them, or square in our case, it expands to E^2 - px^2 - py^2 - pz^2
:) ). That and I don't assume quantities to be 4-vectors unless otherwise specified. (But in this context, I certainly should have. What a dummy.)
Ooops! Sorry. Writing math in ascii can be confusing (for me
Over in the sense that all that's left are questions like 'What is energy?' Just like the future of physics since 1894 lay in the seventh decimal place.
Yes, but I did say it all COULD be over in 50 years. I'm not going to make a solid assertion that we're nearing the end, like Maxwell did. However, I don't believe it would be a shock if we had a theory of everything within that time frame. Certainly if the LHC confirms the existence of the Higgs boson(s), and finds evidence of supersymmetry within the next 10 years, we could be looking at that outcome.
it will never be over. the more we learn about nature, the more opportunities for speculation open up.
.. what? .. early on in 20th century? If there's any "deeper understanding" gained since it certainly didn't make it into the wild yet...
No, the more we learn about nature, the closer we come to the truth, which may or may not be open ended. Asserting that it will never be over assumes more knowledge than any of us have.
I may be wrong on that but it certainly seems that particle physics didn't really make any progress since quantum theory was accepted in
Given that in this day and age that popular media still represent the electrons in an atom following exact orbits in the fashion of newtonian mechanics is a pretty good indication that very little of modern physics has made it 'into the wild'.
Yes it does: Coincidentally it's exactly ZERO!
=> p^2 = 0 => |P| = E
(HEP notation: c=1)
Rest mass is zero, so magnitude(squared) of momentum is zero? Dunce.
m=0 => E^2 = p^2 + m^2 = p^2
=> |p| = E (within a factor c, anyway)
And with the LHC in development, here's hoping for another 50!
With the LHC in development, it could be all over within another 50 years. (Over in the sense that all that's left are questions like 'What is energy?')
Stop smoking - caffeine and cigarettes often go together.
Actually, the human body metabolizes caffeine at about twice the rate in the presence of nicotine. So if you quit smoking, you should cut your caffeine consumption in half at the same time.
Radiation is not nearly as efficient as conductiion hence the need for so many fins on a heat sink. So I still think it would overheat extremely fast.
I think you'll find that the fins are to increase surface area for the purposes of convection. Convection of course dominates radiative transfers in a fluid like air.
As for radiative cooling in space, a quick ball park calculation is quite educational:
Objects emit radiation depending on their temperature, according to Stefan's law. They also absorb radiation from their surroundings according to the same equation, hence we can express the following formula for net power emitted as
P_net = {sigma}*A*e*(T^4 - T_0^4)
Here {sigma} is the stefan-boltzmann constant, 5.67e-8 W/(M^2*K^4), A the surface area of the object. T is the temperature of the object, and T_0 that of the background. e is the emissivity of the object, which we will assume to be 1 (perfect blackbody).
I saw a photo of the thermometer displaying -46 deg C(=227 K), and standard Pentium 4 3GHz apparently consume about 80 watts of power. We'll therefore assume that the madly overclocked P4 produces 200W of heat. The question is then, what area of radiator is required to maintain the chip's temperature, given that the temperature of deep space is about 3K (cosmic background radiation)?
A = P_net / ( {sigma} *(T^4 - T_0^4) )
= 200 / (5.67e-8 * (230^4 - 3^4) )
~= 1.3 m^2
An area of 1.3 m^2 corresponds to a sphere of radius 30cm. Conclusion: Put the chip in good thermal contact with a well-emitting sphere big enough to contain the chip and motherboard, and it'll probably be fine.
"Dear Slashdotters,
next time you gang rape someone's server you wanna check that they're not standing beside it?
Sincerely,
[some fried webmaster]"
--
By reading this message you agree to grant me root access to your computer.
And it wasn't even in a language I understand. Goddamnit!
Actually no, It would overheat quite quickly as a vaccuum is a very good insulator (heh some would say almost perfect).
Aside from RADIATIVE heat exchange of course. Dewar flasks use a vacuum gap for insulation, but the glass is coated with a highly reflective (and hence poorly emissive) metallic film. Paint the damn thing black, and it'll bleed plenty of heat off into the 2.7K hell that is space.
Ha, no, they recently got fermionic atoms to form a BEC. ;)
I know, it's a trick. The fermionic atoms pair up. Weird trick, I don't really get it. (How are they overlapping enough do that in the first place? Damn quantum mechanics.)
;)
;) )
Thanks for the cool link! They overlap because the de Broglie wavelength of the particle is inversely proportional to its momentum, and the particle can't be located to any more accuracy than its wavelength, hence at low temperatures the atoms are spread all over the place. This is also how the BCS theory explains superconductivity (pairing of electrons in that case), but I guess you probably know that
Also of relevant (to this thread, not the story) interest is that during the formation of a neutron star, there is a period during which the iron atoms of the stellar core pair up and hence exhibit superfluid behaviour, before their electrons are crushed into their nuclei.(not that I've ever met a forming neutron star, of course
A windfarm is [multiple] big steel poles with turbines and big steel blades on top. How is that 'heavy industrial work'? It's much less 'heavy' than building a few houses, for example.
What part of building [multiple] big steel poles doesn't consume loads of energy? Is it the mining of the iron ore? The furnaces? And what part of digging big holes in the ground with smog-belching machinery and filling them with concrete (so the windmills don't, you know, blow over in the wind) doesn't?
But I thought it was simply a matter of temperature...it was just we don't have any way to get them down that low if they keep bouncing off each other.
I could be wrong, but I think that many-body interactions can change the internal states of the atoms, which of course must be the same across the board for the condensate to form.
In a nutshell, BECs are formed by applying a magnetic field, which is essentially a 3D SHO potential (mass on a spring). The atoms are cooled by lasers, craftily 'detuned' from the resonant frequency of the atoms, so that, due to the Doppler effect, atoms approaching the laser experience a retarding force, while atoms receding from the laser experience very little force. In this manner the gas sample can be cooled to ~1 microKelvin (?), which is still far too warm for condensation to occur.
The magnetic field is then manipulated to form a 'cup' which holds the atoms. The walls of the 'cup' are gently rolled back, so that the most energetic of the atoms 'boil off' the top, taking excess energy & entropy with them (evaporative cooling), and the remaining atoms rethermalize at a lower temperature.
Once a significant number of atoms fall into the ground state of the SHO, the rest quickly follow, as the probability of scattering into a given state greatly increases with the number of atoms in that state. (this is entirely analogous to photons in a laser all precipitating into the same state, for the same reasons, forming a coherent beam. And it only occurs for atoms which are bosonic, ie those for which #p + #n + #e = even)
Why couldn't we use Wind-power to extract Hydrogen from water? That seems like an infinite supply of hydrogen right there...
Because a)not a lot of people honestly fancy having a windmill farm in their backyard,
b) there is only a finite area on which we can build them,
and c)it takes alot of heavy construction work to build them, which pollutes the environment, and it therefore takes a while for the things to pay for themselves ecologically.
Don't get me wrong, this still reduces our dependence on oil, and will be a huge help to city pollution, but I think we need to quickly figure out some way to make hydrogen cheaply and cleanly. Maybe nuclear powered hydrogen production plants? Just thinking...
I'm inclined to agree with you. Electric cars and such are pointless (from an environmental perspective), if you have to charge them from a wall socket which is powered by a coal power station (or a fission reactor, until such time as we figure out WTF to do with the waste), especially considering the massive inefficiencies between the station and the socket.
These new technologies need to be developed with an eye on the ultimate goal of efficiently distributing and storing energy produced in clean fusion power stations, when such stations are realised. Otherwise it's only going to help the oil cartels retain market share when we stop using oil, and kid some naive people into thinking they're helping things.
But assuming you mean 'near 0 Kelvin', like d00ket pointed out, things get really weird down there. Some substances don't appear to have freezing points, there is no state below 'liquid'...they just move slower and slower. And some freeze quite normally, then do another transition way down there where they move back to a liquid like substance.
It should be noted, in the case of Bose Einstein Condensates, that it isn't simply a matter of temperature. BECs are formed by cooling a gas sample (with lasers, believe it or not) at extremely low pressure. This is because the transition must occur directly from the gaseous phase to the condensate phase. A low pressure ensures that collisions between the atoms are rare, and that most all collisions occur between 2 atoms. Interactions between 3 or more atoms lead to the liquid and solid phases of the element at those temperatures, and preclude the formation of the condensate.
At precisely absolute zero, everything is solid. Movement even on the atomic level requires kinetic energy; the presence of kinetic energy means the temperature is a tiny fraction above absolute zero.
Absolute zero would correspond to a complete absence of movement, which is impossible. This can be seen as a consequence of a few features of quantum mechanics. One of the most intuitive ways to show it (IMHO) is as follows:
The Heisenberg Uncertainty Principle states that the product of the uncertainty in position and the uncertainty in momentum of a particle is greater than a small constant.
A motionless particle would have a completely certain velocity (zero), and a constant position. Hence both uncertainties would be zero, and their product would therefore be zero, and not greater than h-bar/2. Therefore motionless particles are prohibited, and absolute zero is unattainable.
I will buy one when it runs on my cynicism and comes with an ipod holder.
CBG: A cynicism powered scooter? I really doubt that will ever-
[KA-BOOM!]