Galaxies do not emit radiation waves comparable to sonic booms when surpassing the speed of light during cosmic expansion. The expansion of space does not imply absolute motion for galaxies, and locally, stars emit light independently of this expansion. Cosmic inflation occurred in the early universe before the formation of stars and galaxies, making the concept of "speed" complex in curved spacetime. Additionally, particles exceeding the speed of light in a medium produce Cerenkov radiation as they decelerate.
PREREQUISITESAstronomers, physicists, and students of cosmology interested in the dynamics of cosmic expansion and the behavior of light in curved spacetime.
No. When space expands, there is no sense in which a galaxy has absolute motion. Locally, stars will emit light independent of the expansion of space. There's nothing happening locally to affect the emission of light.Adel Makram said:TL;DR Summary: Do galaxies that have surpassed the speed of light during the cosmic inflation process emit radiation waves comparable to the sonic boom when an aeroplane breaches the sound barrier?