Analogue gravity is a research field that investigates phenomena from general relativity—such as black holes and the expansion of the universe—using other physical systems like fluids, Bose-Einstein condensates (BECs), and optical media. The discipline relies on a mathematical isomorphism: the equations governing the propagation of small perturbations (like sound waves or light pulses) in a moving medium are identical to those describing fields in curved spacetime.

Artificial Horizons In analogue systems, researchers create artificial event horizons. For example, in a flowing fluid, if the fluid's velocity surpasses the local speed of sound, it creates a supersonic region. Sound waves inside this region cannot propagate upstream against the flow, resulting in an "acoustic event horizon" or a "dumb hole" (the acoustic equivalent of a black h ...