A question regarding time-dilation and heat

[Taitertots]

As relative time changes, does relative heat change as well?

That is to say if I watched a person passing at the speed of light would their apparent heat change as well as their relative time rates.

[RandomThoughts]

1. Heat is a rate of vibrations of atoms.

So it would be presumed in time dilation it would look cold from outside observer.

Since the measure of vibration of atoms would be less.

Or it is easier to say heat is the radiation of energy by vibration, and that would be less.


Probably why people are shown to freeze when going through things in scifi like stargates and stuff like that.

[Taitertots]

2. What about the states of matter?

Does water moving at the speed of light look like ice or really cold water(EDIT) to an outside observer?

[Xipe Totec]

3. Temperature is the average rate of vibrations of atoms, yes. But heat? nt

[MannyGoldstein]

4. this is probably totally wrong, but...

Maybe there'd be a Doppler shift of the emitted blackbody radiation, which would look like a change in temp?

[izquierdista]

5. Heat is an internal property; apparent motion is external

Which is to say that you have to be inside their inertial reference frame if you want to accurately measure their temperature. If you are external to it, then the light coming at you is red or blue shifted depending on the relative motion. If you know that relative motion and can correct for it, then you can subtract it out and infer the temperature.

I hope this answers the question. Heat and temperature are not the same thing, but are related by the Maxwell relations. If you mean heat, then you may need to know more about the body than just its velocity, things like work and entropy enter into the calculation.

[Taitertots]

6. Updated Explanation: A thought experiment

So, I'm sitting in orbit as a craft comes past me at 99.999% the speed of light. I look at the person in the craft and they are holding a glass of water. How does the relative time difference effect the motion of the atoms in the water glass (temperature)?

I would think it would make it seem as if the water is colder because the atoms would appear to be moving slower.

[izquierdista]

7. Let's think this through

If Capt. Picard is drinking a glass of liquid water as he comes at you, do you see a glass of steam? And as he passes you and recedes, does it becomes a glass of ice? --No.

The temperature of the water is determined by the motion of the water molecules in their own inertial reference frame. When you look from one frame into another, you are going to see properties as they are in that frame. I would say that you can't use relativity to change intrinsic thermodynamic properties as viewed from another frame. Extrinsic properties sure; the volume of the object as it approaches and recedes from you will have its dimensions changed.

Good question, I wish I could hear Feynman's answer to it.

on edit: It's late and I got my red and blue shifts mixed up.

[struggle4progress]

8. Relativistic Thermodynamics

<Physics News Update | American Institute of Physics>
Number 843 #1, October 19, 2007 by Phil Schewe
http://www.aip.org/pnu/2007/split/843-1.html