Thebe or ', is the fourth of Jupiter's known moons (by distance from the planet). It was found by Stephen P. Synnott in images from the "Voyager 1" space probe taken on March 5, 1979 and was given the designation '. Later, it was found on images dating back to February 27, 1979. In 1983 it was officially named after the mythological nymph Thebe who was the daughter of the river god Asopus and a lover of Zeus (the Greek equivalent of Jupiter).