Relativistic Thermodynamics: A Modern 4-Vector Approach
Figure 5
(a) Cavity with walls at temperature filled with thermal radiation (photons) frequency (monochromatic approximation). In frame linear momentum for this ensemble of photons is zero and its energy function is . (b) In frame , the same ensemble of photons, with frequencies , (relativistic Doppler effect) and (aberration effect), has linear momentum , according to the principle of inertia of energy, and total energy .
