In elementary school I was taught that the Earth has exactly one natural satellite: The Moon. Then I heard, within the last year, that there was some small (as in, within a few dozen meters in diameter) chunk of rock that orbits the Earth, that can only be detected with specialized scientific equipment.
AFAIK one known, the one you are referring to may be what I remember being described as a quasi satellite which more co-orbits the sun then orbits the earth, but hyped as a second moon. There are several of those