  A charge moving freely in orbit around the Earth radiates according to
Larmor's formula. If the path is closed, it would constitute a perpetuum
mobile. The solution to this energy paradox is found in an article by C. M.
DeWitt and B. DeWitt from 1964. The main point is that the equation of motion
of a radiating charge is modified in curved spacetime. In the present article
we explain the physics behind this modification, and use the generalized
equation to solve the perpetuum mobile paradox.
