| Correct. > Seems like another one of those relativity related paradoxes. Only fast-moving observers (relative to the CMB) are seeing constant pair production from the CMB photons? Both observers agree about pair production. Pair production obeys conservation of momentum and energy — although the equations allow both to be conserved with two photons interacting, the practical effect here is CMB photons interacting with the spaceship hull: the observer in the CMB-rest-frame will see very low energy photons doing this with a high-velocity hull, and the spaceship frame will see very high energy photons doing this with a stationary (to them) hull. That said, I'm told that accelerating observers can, during the acceleration, disagree about what particles exist around them: https://en.wikipedia.org/wiki/Unruh_effect (Hmm, and now I'm wondering if the Unruh effect is really as described — if different quantum fields contribute at different rates, or have cut-offs at different scales, that would automatically also create something that, if you squint, will look a bit like an approximation of MOND… sadly, this is beyond my competence at this time). |