Besides reversed values for the index of refraction, Veselago predicted the occurrence of reversed Cherenkov radiation in a left-handed medium. Whereas ordinary Cherenkov radiation is emitted in a cone around the direction in which a charged particle is travelling through the medium, reversed Cherenkov radiation is emitted in a cone around the opposite direction. Reversed Cherenkov radiation was first experimentally demonstrated indirectly in 2009, using a phased electromagnetic dipole array to model a moving charged particle. Reversed Cherenkov radiation emitted by actual charged particles was first observed in 2017.