https://doi.org/10.1140/epjp/i2012-12072-4
Regular Article
On the inertia of heat
Max-Planck-Institut für Gravitationsphysik, Am Mühlenberg 1, D-14476, Golm, Germany
* e-mail: smerlak@aei.mpg.de
Received:
29
June
2012
Accepted:
29
June
2012
Published online:
6
July
2012
Does heat have inertia? This question is at the core of a long-standing controversy on Eckart's dissipative relativistic hydrodynamics. Here I show that the troublesome inertial term in Eckart’s heat flux arises only if one insists on defining thermal diffusivity as a spacetime constant. I argue that this is not the most natural definition, and that all confusion disappears if one considers, instead, the space-dependent comoving diffusivity, in line with the fact that, in the presence of gravity, space is an inhomogeneous medium.
© Società Italiana di Fisica and Springer, 2012
