Absolute Zero

[fakeitormakeit]

I read sometime about this awhile ago, very interesting material

[liquidsky]

I figure it is because to lower the temperature of an object, it would have to transfer its energy to another sample of matter which has an even lower temperature (this would be of course, because energy moves from high to low; entropy and all that). So basically the final ....

 

 

 

In practice to cool something close to absolute zero lasers are used whereby their frequency is just a touch below the frequency that the atoms (in the gas or molecule) will absorb it.

 

Atomic motion towards the laser will cause the light to be doppler shifted to a higher frequency - absorbing the momentum of the light and 'push' it in the direction of the laser light. On average, the atoms will be 'pushed' opposite to their motion and thus eventually slowed down.

 

If your interested in this and want more (and better) information look into the text from the 1997 Nobel Prize for Physics

 

 

 

Also just to clarify, at absolute zero (or the limit as you approach AZ, or however you want to look at it), the system is in its lowest energy state (ground state), which is not necessarily equal to 0.

[ironmaiden666]

Nah, I find this interesting as well. But how can atoms become waves? I've heard of electrons behaving like waves, but not atoms. Could you elaborate on that?

 

 

 

http://en.wikipedia.org/wiki/Bose_einstein_condensate

 

 

 

It says that when the atoms become supercooled to these temperatures the atoms colapses and becoems wave like.

[liquidsky]

It says that when the atoms become supercooled to these temperatures the atoms colapses and becoems wave like.

 

 

 

You can think of atoms in a bose-einstein condensate as being all 'coherent' waves of matter (in their lowest quantum states of motion) - in the same way as laser light consists of coherent photons.

 

And therefore you can have fun playing with their wave-like properties (nonlinear optics, diffraction, interference, etc..)

[assassin_696]

Yeah, the Bose-Einstein condensate phenomenen is a fascinating one, a friend pointed me towards it a while ago and I wasted a good lunch hour reading all about it.

 

 

 

As has been said, what basically happens is a big clump of atoms that will normally exist seperate from each other collapse into the lowest available energy state, so they all kind of merge to form a point, a new state of matter.

 

 

 

The stuff about particle-wave duality applies to any particle, what makes the BEC special is that this kind of quantum phenomena are suddenly directly observable on a macroscopic scale.

 

 

 

It's also very interesting how they cool stuff down to that kind of temperature using very advanced lasers, I remember watching a fun tutorial on it a while ago but I can't find the link.

 

 

 

For example, I remember hearing that specific nuclear reactions within the sun can turn hydrogen atoms into useable energy, if I recall correctly :-k . Not exactly an earthly reaction. The same thing goes for that example- those kind of temperatures aren't exactly commonly found in the universe :-w . Or, really, at all :P .

 

 

 

Nuclear fusion reactions :) The Sun smacks two hydrogen atoms together to form one helium atom, but one helium atom is a little bit lighter than two hydrogen atoms, so the extra mass has to go somewhere right? Well, since E=mc^2, the little bit of mass is converted into quite a lot of energy, and that's what fuels pretty much all stars (heavier stars can fuse heavier elements, and dying stars can fuse very heavy elements, which is why we know that we're a second generation star system).

[NickCini]

I've always been very interested in Absolute 0, but something that has always confused me...

 

 

 

Absolute zero is when all particle movement stops. Particles have to move to exist, so therotically the matter would disappear. What would happen to that space where we reached that temperature? Would it spread? Would we just have a little space with nothing there forever? What about anything that comes in contact with that space? So many questions...

 

Why would something have to move in order to exist?

 

 

 

Some scientific laws. All my notes on this are 4000 miles away, so I can't look it up to give you solid proof, but overall all matter is in constant, random motion. As the matter cools the movement slows down, but never stops. There's some theories floating around out there that if matter were to stop moving it would cease to exist. The matter I'm talking about is, of course, atoms and the like so you don't have to worry about your non-moving table to disappear as all its atoms are in constant, random motion.

 

 

 

:XD:

 

 

 

With reference to the question in the first post, most people who can even vaguely comprehend this sort of thing do find it interesting. I think it's interesting, obviously most people on this thread do.

 

 

 

Unfortunately we are the minority. The majority would call us Geeky. So no you're not alone in liking this. But yes. We are geeks.

 

 

 

Geek power!

[TotalTalker]

These sort of "geeky" things get you farther in life than if you are dumb.

 

 

 

This is fascinating, and im sure ive heard of this before. About the particles not moving at absolute zero, or something like that.

[trapical]

Chuck Noris can know the exact velocity and location of a subatomic partical AT THE SAME TIME!

 

 

 

/Heisenberg uncertainty rule ftw!

[nightshade53]

If you are interested in this type of science then I highly recommend that you get hold of a copy of Bill Bryson's "A Short History of Nearly Everything". It is truly a fascinating read.

 

 

 

I even got the Amazon link for you :)

 

Amazon UK

 

Amazon America

 

 

 

---

 

 

 

Fun fact: If you were to bring an object the size of, oh, an ice cube, lets say, the air in the room would instantly turn solid because all the heat is heading straight into the object. really awesome.

Thats why ice makes drinks cold. Even awesomer!

 

indeed. heat has a tendency to go from high to low, like particle diffusion. Something cold appears, all the heat goes to equalize the temperatures. Fun activity: put some ice in a frying pan. turn up the heat. stick your hadn in the water before most of the ice melts. it will be the same temp, becauuse the heat is focusing on the frozen ice, not the liquid. ive done it before, rather cool.

 

 

 

This is explained by the Specific Latent Heat and Specific Heat Capacity rules. These basically say that Energy is absorbed/given out by a Change of State of Matter, and also a change in temperature of Matter. During a change of state, energy is absorbed/given out without a change of temperature.

 

 

 

If this thread interests you, then an investment in the above mentioned book will pay off :)

[assassin_696]

Chuck Noris can know the exact velocity and location of a subatomic partical AT THE SAME TIME!

 

 

 

/Heisenberg uncertainty rule ftw!

 

 

 

 

 

 

:P

[The Real ET]

Nah, I find this interesting as well. But how can atoms become waves? I've heard of electrons behaving like waves, but not atoms. Could you elaborate on that?

 

 

 

http://en.wikipedia.org/wiki/Bose_einstein_condensate

 

 

 

It says that when the atoms become supercooled to these temperatures the atoms colapses and becoems wave like.

 

 

 

 

Just found this. :

 

That'd be the opposite of absolute zero, a point above which atoms break and become energy, so that ll matter ceases to exist.

 

 

 

Wikipedia is the devil, do not ever trust it as your only source in any research (personal or professional) purposes. If you check up with the sources, use them as any information to cite. But, yeah... wikipedia = bad.

 

 

 

Enough of that, does anyone know how laser cooling actually works? I mean on a molecular level, not just a general "you shoot stuff with a special laser and it gets cold".

[Lenin64]

Nah, I find this interesting as well. But how can atoms become waves? I've heard of electrons behaving like waves, but not atoms. Could you elaborate on that?

 

 

 

http://en.wikipedia.org/wiki/Bose_einstein_condensate

 

 

 

It says that when the atoms become supercooled to these temperatures the atoms colapses and becoems wave like.

 

 

 

 

Just found this. :

 

That'd be the opposite of absolute zero, a point above which atoms break and become energy, so that ll matter ceases to exist.

 

 

 

Wikipedia is the devil, do not ever trust it as your only source in any research (personal or professional) purposes. If you check up with the sources, use them as any information to cite. But, yeah... wikipedia = bad.

 

 

 

Enough of that, does anyone know how laser cooling actually works? I mean on a molecular level, not just a general "you shoot stuff with a special laser and it gets cold".

You shoot objects with a special..oh wait. Nevermind. :

[Led-Zeppelin]

I was watching a documentary about renewable power and all the things people are creating. One was a huge solar power plant in the Aussie desert. One was a wind turbine farm.

 

 

 

The other was a nuclear fusion reactor, where they superheat water into plasma I think it was. It is so effective, if you were to use a tub of water, it would provide one person with enough power for all their car and home needs for 30 years. They have a small one already built, but don't expect a full size working one to be built for another 30 - 50 years I think it said.

[Kill_Thomas9]

I was watching a documentary about renewable power and all the things people are creating. One was a huge solar power plant in the Aussie desert. One was a wind turbine farm.

 

 

 

The other was a nuclear fusion reactor, where they superheat water into plasma I think it was. It is so effective, if you were to use a tub of water, it would provide one person with enough power for all their car and home needs for 30 years. They have a small one already built, but don't expect a full size working one to be built for another 30 - 50 years I think it said.

 

 

 

Sounds interesting.

 

 

 

And then we can launch all the nuclear waste into orbit around the planet! That way we wont have to worry about it for another 1000 years, by which time I'm sure it can be disposed of!

 

 

 

Nuclear Power Ftw!

[SupportMage]

I was watching a documentary about renewable power and all the things people are creating. One was a huge solar power plant in the Aussie desert. One was a wind turbine farm.

 

 

 

The other was a nuclear fusion reactor, where they superheat water into plasma I think it was. It is so effective, if you were to use a tub of water, it would provide one person with enough power for all their car and home needs for 30 years. They have a small one already built, but don't expect a full size working one to be built for another 30 - 50 years I think it said.

 

 

 

Sounds interesting.

 

 

 

And then we can launch all the nuclear waste into orbit around the planet! That way we wont have to worry about it for another 1000 years, by which time I'm sure it can be disposed of!

 

 

 

Nuclear Power Ftw!

 

 

 

Do you not watch Futurama?!

 

 

 

Also, I saw a thing on the Nat Geo channel about the stars. They combine huge amounts of elements during their life, until they're left with iron, which absorbs energy in it's fusion. Then they explode and send all the material into space, and that's where we get out resources. Science ftw.

[liquidsky]

Enough of that, does anyone know how laser cooling actually works? I mean on a molecular level, not just a general "you shoot stuff with a special laser and it gets cold".

 

 

 

Hey mate, I posted a brief outline a bit further above on page 2 of this thread. Let us know if you have more questions on it

[The Real ET]

Enough of that, does anyone know how laser cooling actually works? I mean on a molecular level, not just a general "you shoot stuff with a special laser and it gets cold".

 

 

 

Hey mate, I posted a brief outline a bit further above on page 2 of this thread. Let us know if you have more questions on it

 

 

 

Thanks mate, it all makes sense now. I still wonder about a lot of things though... *pokes page 1 post*

[meol]

It requires very specific reactions and conditions for matter to become energy; it's not exactly something you see every day (so no, all matter is not going to become energy [until end of the hypothesized Big Crunch anyways], even if it's possible it's source is really a string of raw energy).

 

 

 

For example, I remember hearing that specific nuclear reactions within the sun can turn hydrogen atoms into usable energy, if I recall correctly :-k . Not exactly an earthly reaction. The same thing goes for that example- those kind of temperatures aren't exactly commonly found in the universe :-w . Or, really, at all :P .

 

In fact, physicians are actively working on conducting nuclear fusion in the Earth as well, (it'd be the best source of electricity ever!). The only problem is that the most basic form of fusion would require immense temperatures and pressure, but at the end it'd produce a stable chain reaction

 

So far, the only fusion reactions produced by humans are the ones present in hydrogen-bombs.

 

During that process, hydrogen isotopes (deuterium and tritium) get "combined" and build a helium atom, and some of the mass is transformed into energy during the process. (The same already happens with nuclear fission; some part of the matter is transformed into energy)

 

 

 

Oh, and dang Planck's got a lot of crud named after him...

 

All the Planck units, the theoretical maximum and minimum amounts of time, length, mass, energy, etc.

 

...Wikipedia is the devil, do not ever trust it as your only source in any research (personal or professional) purposes. If you check up with the sources, use them as any information to cite. But, yeah... wikipedia = bad...

 

Here you are. :

[liquidsky]

Hey, I read your question on what would happen to something at az.

 

 

 

At az atoms still have an energy known as zero point (quantum) energy. (In fact for liquid helium this is greater than it's latent heat of evaporation - why it won't crystallize unless at very high pressures).

 

Because there is this zero point energy, the universe wouldn't blow up, collapse, or anything like that. Your silicon solar cell won't work because the valence band is full and conduction band (where electrons can move) is empty, hwoever the atoms still exist and electrons still "orbit" - but in their lowest energy state.

 

Current theory rules out the possibility of reaching 0K (hup, thermodynamics..) so the next best we can do is talk about what happens at very close to az - things like bec.

[The Real ET]

It requires very specific reactions and conditions for matter to become energy; it's not exactly something you see every day (so no, all matter is not going to become energy [until end of the hypothesized Big Crunch anyways], even if it's possible it's source is really a string of raw energy).

 

 

 

For example, I remember hearing that specific nuclear reactions within the sun can turn hydrogen atoms into usable energy, if I recall correctly :-k . Not exactly an earthly reaction. The same thing goes for that example- those kind of temperatures aren't exactly commonly found in the universe :-w . Or, really, at all :P .

 

In fact, physicians are actively working on conducting nuclear fusion in the Earth as well, (it'd be the best source of electricity ever!). The only problem is that the most basic form of fusion would require immense temperatures and pressure, but at the end it'd produce a stable chain reaction

 

So far, the only fusion reactions produced by humans are the ones present in hydrogen-bombs.

 

During that process, hydrogen isotopes (deuterium and tritium) get "combined" and build a helium atom, and some of the mass is transformed into energy during the process. (The same already happens with nuclear fission; some part of the matter is transformed into energy)

 

 

 

Oh, and dang Planck's got a lot of crud named after him...

 

All the Planck units, the theoretical maximum and minimum amounts of time, length, mass, energy, etc.

 

...Wikipedia is the devil, do not ever trust it as your only source in any research (personal or professional) purposes. If you check up with the sources, use them as any information to cite. But, yeah... wikipedia = bad...

 

Here you are. :

 

 

 

Good poster. I still don't know if I trust this Cecil guy, but I do like this better than Wikipedia. =P

[BlueTear]

So far, the only fusion reactions produced by humans are the ones present in hydrogen-bombs.

 

During that process, hydrogen isotopes (deuterium and tritium) get "combined" and build a helium atom, and some of the mass is transformed into energy during the process. (The same already happens with nuclear fission; some part of the matter is transformed into energy)

Actually, there is at least one test reactor, a fusion reactor where the energy used to maintain the fusion reaction is "slightly" larger than the actual output. Joint European Torus or somesuch.

[The Real ET]

So far, the only fusion reactions produced by humans are the ones present in hydrogen-bombs.

 

During that process, hydrogen isotopes (deuterium and tritium) get "combined" and build a helium atom, and some of the mass is transformed into energy during the process. (The same already happens with nuclear fission; some part of the matter is transformed into energy)

Actually, there is at least one test reactor, a fusion reactor where the energy used to maintain the fusion reaction is "slightly" larger than the actual output. Joint European Torus or somesuch.

 

 

 

Really? I've never heard of this. Source, proof, or what have you?

[BlueTear]

Really? I've never heard of this. Source, proof, or what have you?

 

 

 

http://www.jet.efda.org/

[meol]

Oh, but it's only a research centre, and it still can't sustain a stable exothermic reaction. Oh, well I guess I'll have to wait some more years for a real fusion plant.

[The Real ET]

Yeah... fusion for the win!! :thumbsup: