Temperature in different frames

In summary, the temperature of a body depends on its frame of reference and the internal kinetic energy does not necessarily depend on the frame of reference, especially at relativistic velocities. However, in regions with a large amount of curvature, defining temperature for a specific frame becomes more challenging and temperature may be loosely defined for each point in space time. Additionally, there is ongoing debate about the best way to handle relativistic thermodynamics.
  • #1
SandeshPhy
25
0
Does the temperature a body depend on its frame of reference?
Does the internal kinetic energy depend on frame of reference?
In short does it depend on velocity of body at relativistic velocities?

the body doesn't know it is moving at that velocity,so i think temperature must not depend on velocity
 
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  • #2
In reasonably flat regions, the temperature of a fluid or a solid is defined for the frame in which the centre of mass is at rest. Any energy added by moving to another frame is kinetic energy but not heat, because it is associated with directional momentum. There are probably considerable difficulties extending this definition to regions of space time with a large amount of curvature, as one frame will not do but, in such regions, a temperature may be loosely defined for each point in space time, by using a smaller region around that point. This temperature will be frame independent for the same reason.
 
  • #3
Usually temperature is only defined in one frame, the rest frame of the thermodynamic fluid.

There are some formulations where inverse temperature is part of a 4-vector, rather than a scalar - much as energy is part of the energy momentum 4-vector. See http://arxiv.org/abs/physics/0505004 ,and not that there is some controversy over the best way to handle relativistic thermodynamics.
 

1. What is the concept of temperature in different frames?

Temperature in different frames refers to the measurement of heat or cold in a particular object or system based on the reference frame it is being observed from. It takes into account the relative motion and position of the observer and the object being measured.

2. How does temperature change in different frames of reference?

The temperature of an object or system may appear different when observed from different frames of reference due to the effects of relative motion and position. This is known as the Doppler effect, where the wavelength and frequency of thermal radiation may appear to change.

3. Can temperature be the same in all frames of reference?

Yes, temperature can be the same in all frames of reference if the object or system is at a state of thermal equilibrium. This means that there is no net flow of heat between the object and its surroundings, regardless of the reference frame.

4. How does the speed of an object affect its temperature in different frames?

The speed of an object can affect its temperature in different frames due to the Doppler effect. As an object moves towards an observer, the thermal radiation emitted by the object will appear to have a shorter wavelength and higher frequency, resulting in a higher temperature. Conversely, as an object moves away from an observer, the thermal radiation will appear to have a longer wavelength and lower frequency, resulting in a lower temperature.

5. What are the practical applications of considering temperature in different frames?

Consideration of temperature in different frames is important in various fields such as astrophysics, where the Doppler effect is used to study the temperature and movement of distant objects in space. It is also important in engineering, where the effects of relative motion and position on temperature must be taken into account for accurate measurements and calculations.

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