What is the Temperature of an atom moving at the speed of light?

AI Thread Summary
An atom cannot move at the speed of light due to the principles of special relativity, which state that massive particles require infinite energy to reach that speed. Consequently, the concept of temperature for an atom moving at light speed is moot, as temperature is a property of collections of particles, not individual atoms. Discussions also clarify that while a single photon cannot have a temperature, a single atom can, but only when part of a larger ensemble. Theoretical considerations suggest that if it were possible for atoms to vibrate at light speed, it would imply infinite energy and mass, making the scenario physically impossible. Ultimately, the conversation emphasizes that asking about the temperature of an atom at light speed is fundamentally flawed within our current understanding of physics.
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What is the Temperature of an atom moving at the speed of light?

Since absolute zero is the lack of activity and energy and

since no physical object can move faster than the speed of light

What is the temperature of an atom moving at the speed of light?

Light is either a particle or a wave or both or neither .. the temperature of light would not be the temperature of an atom moving at the speed of light.

Curious
 
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Massive particles can not travel at the speed of light, so most of your question is meaningless.

A gas of photons can have a temperature, but a single photon can not. Temperature is a property of large collections of objects and a single object can not have a temperature.
 
ok so therefore there is no answer since massive particles cannot travel at the speed of light .. interesting

which brings up the question .. why?

ok I said one atom .. please excuse my ignorance

a group of atoms moving at the speed of light

but since a massive atom cannot move at the speed of light .. that is really going to slow down space travel.
 
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Tameas001 said:
ok so therefore there is no answer since massive particles cannot travel at the speed of light .. interesting

which brings up the question .. why?
.

Because it would take infinite energy and we don't have that much.
 
Tameas001 said:
ok so therefore there is no answer since massive particles cannot travel at the speed of light .. interesting

which brings up the question .. why?

ok I said one atom .. please excuse my ignorance

a group of atoms moving at the speed of light

but since a massive atom cannot move at the speed of light .. that is really going to slow down space travel.

See "special relativity"

Also the temperature of a gas moving near the speed of light is given by the same equation as a gas moving much less than the speed of light, the ideal gas law (PV=nRT)
 
Tameas001 said:
but since a massive atom cannot move at the speed of light .. that is really going to slow down space travel.

It won't slow down space travel.
With a ship speed close to the speed of light, the travel time would be quite short for the passengers of the ship, due to relativistic effects.
So for example traveling a 100 light years distance could take only a few years for the passengers inside the ship. It would still take 100+ years for everyone outside the ship, not traveling with relativistic speed.

And if a ship could travel with the speed of light (not possible, but nice to imagine), the travel time for its passengers would be instant, no matter the distance.
 
Ok .. It would take infinite energy .. agreed

the object would have infinite mass

no single atom can have temperature but two can .. silly notion

and yes it wouldn't slow down space travel since speed is relative to the point you are observing it from.

however I didnt ask if it was possible .. I just asked what would be the temperature of an atom moving at the speed of light. Would this value be the absolute hottest temperature and the equivalent of absolute zero on the temperature scale.

moving does not need to mean traveling it could also mean vibrating as atoms which are hot do.
 
There is something called Planck Temperature, which is supposed to be the absulate limit to temperature. I'm not sure, but I suspect it has something to do with this temperature requiring the atoms to vibrate at the speed of light?
 
Tameas001 said:
Ok .. It would take infinite energy .. agreed

the object would have infinite mass

no single atom can have temperature but two can .. silly notion

and yes it wouldn't slow down space travel since speed is relative to the point you are observing it from.

however I didnt ask if it was possible .. I just asked what would be the temperature of an atom moving at the speed of light. Would this value be the absolute hottest temperature and the equivalent of absolute zero on the temperature scale.

moving does not need to mean traveling it could also mean vibrating as atoms which are hot do.

You mean what do the laws of physics say would happen in a situation which breaks the laws of physics? Do you see the problem here? Unicorns, leprechauns and pixie dust happen.
 
  • #10
Tameas001 said:
no single atom can have temperature but two can .. silly notion

This is wrong. A single atom can and does have a temperature. Pengwuino said a single PHOTON can't have a temperature, not a single ATOM, which definitely can have a temperature.
 
  • #11
Tameas001 said:
What is the Temperature of an atom moving at the speed of light?

Since absolute zero is the lack of activity and energy and

since no physical object can move faster than the speed of light

What is the temperature of an atom moving at the speed of light?

Light is either a particle or a wave or both or neither .. the temperature of light would not be the temperature of an atom moving at the speed of light.

Curious

The point I think you're missing is that temperature is related to the energy of [a collection of] particles, and the energy of a particle can increase without bound, even though its speed must be less than c. There is no maximum temperature.

BBB
 
  • #12
bbbeard said:
The point I think you're missing is that temperature is related to the energy of [a collection of] particles, and the energy of a particle can increase without bound, even though its speed must be less than c. There is no maximum temperature.

BBB

Ok so these people are wasting time and money

Google: Absolute hot :NOVA

or click this link
http://www.pbs.org/wgbh/nova/physics/absolute-hot.html

But you are right in that definition

however temperature by definition is not what I asked

interesting that there is no way to assess the temperature of a single atom.
 
  • #13
cbetanco said:
This is wrong. A single atom can and does have a temperature. Pengwuino said a single PHOTON can't have a temperature, not a single ATOM, which definitely can have a temperature.

A single atom does not have a temperature. The temperature is defined as the derivative of the energy with respect to entropy keeping volume and particle number constant. Say I have a hydrogen atom in its ground state, degeneracy is 2 (one state which can be up state or down state) the next energy level is 6 degenerate (the p-orbitals), it's a finite jump and there's no continuum approximation. Temperature is not defined. In general temperature is only defined relative to the notion of a heat bath (canonical ensemble), in the microcanonical ensemble (isolated system) it is simply a Lagrange multiplier, it doesn't carry the same meaning.
 
  • #14
Tameas001 said:
Ok so these people are wasting time and money

Google: Absolute hot :NOVA

or click this link
http://www.pbs.org/wgbh/nova/physics/absolute-hot.html

But you are right in that definition

however temperature by definition is not what I asked

interesting that there is no way to assess the temperature of a single atom.

Well even intuitively the temperature is the average energy per particle, if you only have one particle...
 
  • #15
maverick_starstrider said:
A single atom does not have a temperature. The temperature is defined as the derivative of the energy with respect to entropy keeping volume and particle number constant. Say I have a hydrogen atom in its ground state, degeneracy is 2 (one state which can be up state or down state) the next energy level is 6 degenerate (the p-orbitals), it's a finite jump and there's no continuum approximation. Temperature is not defined. In general temperature is only defined relative to the notion of a heat bath (canonical ensemble), in the microcanonical ensemble (isolated system) it is simply a Lagrange multiplier, it doesn't carry the same meaning.

so taken as individual atoms they have no temperature but if there is a crowd of them they do have temperature.

so what is the minimum number of atoms that you have to have to say that there is temperature?

what would be the temperature of this minimum crowd of atoms if they were moving/vibrating at the speed of light?

Of course assuming that they are moving/vibrating at the speed of light no matter how impossible that may be to achieve.
 
  • #16
The basic answer was given in the first post, you cannot have atoms moving at the speed of light. You are asking "what happens when I walk through this wall?" You can't walk through a wall so there is no answer. I don't know what else can be said here.The minimum number of atoms? Lots. Again if I tell you "the minimum number is thirteen trillion" what can you use this for? You can research what constitutes a statistical ensemble and where the limits of the continuum model of a fluid breaks down, but the heart of your question still assumes that an impossibility is possible.
 
  • #17
Your question is moot because our current models for physics suggest that the energy required would be, literally, infinite.
 
  • #18
Ok it is infinitely impossible for this to be but

If it did happen

What would be the temperature of an atom or bunch of atoms moving/vibrating at the speed of light?

It should be a simple calculation .. just like they extended to absolute zero as the lack of energy and motion ... what would be the temperature extended the other way to infinite energy and motion at the speed of light.
 
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  • #19
Tameas001 said:
Ok it is infinitely impossible for this to be but

If it did happen

What would be the temperature of an atom or bunch of atoms moving/vibrating at the speed of light?

It should be a simple calculation .. just like they extended to absolute zero as the lack of energy and motion ... what would be the temperature extended the other way to infinite energy and motion at the speed of light.

Hm ... this is not going well. It's been stated a couple of times that you are asking for an answer to the question of what happens if the impossible happens.

Just make up your own answer. It will be just as good as anything anyone else can tell you.
 
  • #20
Yup figured that out a few answers ago

no one knows ..

thank you for your time and patience.
 
  • #21
Tameas001 said:
Yup figured that out a few answers ago

no one knows ..

thank you for your time and patience.

No, I'm afraid you're deeply misunderstanding the situation. It's certainly not that "no one knows". It's not like this is a hole in our understanding or an open area of research. It's completely understood.

The requirement that something can't go faster than the speed of light isn't just qualitatively stitched on, it's not like you use Newton's laws but if you calculate things and you get a velocity equal to or greater than the speed of light these "laws" of physics say "oh, I guess this is forbidden I can't use this" and then you toss it out. The equations that govern the universe themselves have the intrinsic property that you'll never get answers out of them where a particle with mass has a velocity greater than or equal to c. I think the best way for you to get some comprehension of this is to just give you an equation. (Ignoring the rest mass which you can take as a constant) the energy of particle with a mass m and a velocity v is given by

E = \frac{m c^2}{\sqrt{1 - \frac{v^2}{c^2}}}

where c is the speed of light. Play with it. How much energy is needed to achieve a velocity, v, of, say, 50% the speed of light (v=0.5*c)? Well then we get

E = \frac{m c^2}{\sqrt{1 - \frac{(\frac{c}{2})^2}{c^2}}}= \frac{m c^2}{\sqrt{1 - 0.25}}= 1.154 m c^2

Ok, no problem. What if I go 90% of the speed of light (v=0.9*c)? How much energy do I need?

E = \frac{m c^2}{\sqrt{1 - \frac{(0.9 c)^2}{c^2}}}= \frac{m c^2}{\sqrt{1 - 0.81}}= 2.29 m c^2

Ok, great. Now you want the answer to your question? Want to know the energy a particle needs to go the speed of light (i.e. want to know the temperature of a particle moving at the speed of light)? Take v=c and plug it in

E = \frac{m c^2}{\sqrt{1 - \frac{( c)^2}{c^2}}}= \frac{m c^2}{\sqrt{1 - 1}}=

Take your calculator and plug that in. What about a speed greater than c? How much energy/temperature must a particle going at 110% the speed of light (v=1.1c) have. It's not unknown or some mind-boggling question. Let's plug it in and see

E = \frac{m c^2}{\sqrt{1 - \frac{(1.1 c)^2}{c^2}}}= \frac{m c^2}{\sqrt{1 - 1.21}}=

Plug that into your calculator. That IS THE ANSWER. It's not unknown, that's what it is. That's what we knew the answer was over a century ago in 1905 and what we know it is now in 2012. You're not asking a deep penetrating question, it's a simple question with a simple answer which you've been told repeatedly.
 
  • #22
Tameas001 said:
Yup figured that out a few answers ago

no one knows ..

thank you for your time and patience.

It is as unknown as asking what would happen to something at below absolute zero. It just doesn't make sense because that isn't how the universe works.
 
  • #23
Lsos said:
There is something called Planck Temperature, which is supposed to be the absulate limit to temperature. I'm not sure, but I suspect it has something to do with this temperature requiring the atoms to vibrate at the speed of light?

I always thought the Sakharov temperature was the greatest possible temperature?
 
  • #24
rollcast said:
I always thought the Sakharov temperature was the greatest possible temperature?

Any question of "absolute hot" is going to take you into the field of grand unified theories and speculative physics. If the standard model is merged with gravity (through a spin-2 field theory) my understanding is that the result replicates GR and QFT just fine except it renormalizes to infinity. In a nutshell this means that at higher and higher energies gravity should starts running the show relative to the other forces and it will get more powerful as energies increase until its strength becomes infinite,which is why we don't know how to merge GR and QFT, the resulting field theory is what is what is called non-renormalizable. However, I am neither a cosmologist, quantum gravity...ist? or a particle physicist so I could be off the mark.
 
  • #25
I can see there is a clear conflict of concepts in your mind, and that is contributing to your confusion. An atom does not have a temperature.

Also, temperature, even in the context that you use it, is a quantity that can be influenced by many factors. If a body is accelerating in air, there is friction between the air and the body. This increases the body's temperature. If the same operation was done in vacuum, the body's temperature would be much smaller.

At particle level, particles generally exchange energy by interacting with other particles, fields, or radiation.

Let's suppose you have an ideal vacuum, a proton, and some electromagnetic setup that can accelerate the proton. Let's also suppose that your setup is infinitely powerful. In that case, when the proton has 99.99999999999999% the speed of light (supposing it could actually reach this velocity), you can calculate its energy from the formula above.

The fact is that you will never manage to make it surpass the speed of light, no matter how much energy you put in. This is the reason that your question doesn't make sense.

Another way to think of it is that there is an infinite number of energy states which theoretically bring the proton close to the speed of light, so there is no one answer. The answer is, very literally: infinity.

Finally, keep in mind that one reason that it doesn't make sense to talk about temperature at this level of velocities is that, to my knowledge, there is no material that can actually maintain a shape and not be disintegrated into particles when approaching such velocities. The reason for this is that all the energy going into the solid body in order to make it go faster will cause its particles to just come apart from each other.
 
  • #26
maverick_starstrider said:
No, I'm afraid you're deeply misunderstanding the situation. It's certainly not that "no one knows". It's not like this is a hole in our understanding or an open area of research. It's completely understood.

The requirement that something can't go faster than the speed of light isn't just qualitatively stitched on, it's not like you use Newton's laws but if you calculate things and you get a velocity equal to or greater than the speed of light these "laws" of physics say "oh, I guess this is forbidden I can't use this" and then you toss it out. The equations that govern the universe themselves have the intrinsic property that you'll never get answers out of them where a particle with mass has a velocity greater than or equal to c. I think the best way for you to get some comprehension of this is to just give you an equation. (Ignoring the rest mass which you can take as a constant) the energy of particle with a mass m and a velocity v is given by

E = \frac{m c^2}{\sqrt{1 - \frac{v^2}{c^2}}}

where c is the speed of light. Play with it. How much energy is needed to achieve a velocity, v, of, say, 50% the speed of light (v=0.5*c)? Well then we get

E = \frac{m c^2}{\sqrt{1 - \frac{(\frac{c}{2})^2}{c^2}}}= \frac{m c^2}{\sqrt{1 - 0.25}}= 1.154 m c^2

Ok, no problem. What if I go 90% of the speed of light (v=0.9*c)? How much energy do I need?

E = \frac{m c^2}{\sqrt{1 - \frac{(0.9 c)^2}{c^2}}}= \frac{m c^2}{\sqrt{1 - 0.81}}= 2.29 m c^2

Ok, great. Now you want the answer to your question? Want to know the energy a particle needs to go the speed of light (i.e. want to know the temperature of a particle moving at the speed of light)? Take v=c and plug it in

E = \frac{m c^2}{\sqrt{1 - \frac{( c)^2}{c^2}}}= \frac{m c^2}{\sqrt{1 - 1}}=

Take your calculator and plug that in. What about a speed greater than c? How much energy/temperature must a particle going at 110% the speed of light (v=1.1c) have. It's not unknown or some mind-boggling question. Let's plug it in and see

E = \frac{m c^2}{\sqrt{1 - \frac{(1.1 c)^2}{c^2}}}= \frac{m c^2}{\sqrt{1 - 1.21}}=

Plug that into your calculator. That IS THE ANSWER. It's not unknown, that's what it is. That's what we knew the answer was over a century ago in 1905 and what we know it is now in 2012. You're not asking a deep penetrating question, it's a simple question with a simple answer which you've been told repeatedly.

I don't own a calculator nor know how to use one

and since all I asked for was the temperature and since no one has given me an answer I must assume that no one knows

have a nice day


If you have to use math to explain a theory you don't fully understand
 
  • #27
That's an extraordinarily ignorant statement. Physics doesn't just say "what comes up must come down" - it says where and when it comes down, and that requires math. Furthermore, you asked for a number. Providing a number without math is hard to do.

One can easily come to the conclusion that you're more interested in stirring things up than learning anything. If that's not true, you should take a few steps back, reread what you've written, and think about posting in a way that is more positive and constructive.
 
  • #28
Tameas001 said:
I don't own a calculator nor know how to use one

and since all I asked for was the temperature and since no one has given me an answer I must assume that no one knows

have a nice day


If you have to use math to explain a theory you don't fully understand

You have the internet? Then you have a calculator. You've been told the answer repeatedly, it isn't "physics doesn't know" it's infinity/not-defined. It's extremely well known. This isn't exactly new cutting edge physics, special relativity was developed in 1905, that's 107 years ago (since you don't have a calculator)
 
  • #29
Might as well lock this.
 

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