In early September, amateur stargazers and professional astronomers
alike were dumbfounded at the discovery of object J002E3, a chunk of
space debris trapped in an unusual orbit of Earth, not unlike that of a
second, much smaller and more distant moon.

Further investigations by Near-Earth Object Program scientists
suggested that J002E3 is likely not a naturally occurring object. Instead, it's a man-made item (probably a stage of the Saturn V rocket that launched one of the moon-bound Apollo missions between 1969 and 1971) that initially escaped Earth's gravity and was later recaptured by Earth's pull.

Thus, J002E3 became an unintentional satellite, if not a full-fledged
second moon. However, J002E3 is not the only stellar object to have
been captured by the Earth's gravity; certain naturally occurring space
objects have also temporarily entered distant orbital relationships with Earth.
Indeed, one particular three-mile-wide object discovered in 1997 was,
at one point, suspected to be an Earth-orbiting satellite, earning it the
possible distinction of currently being Earth's second moon.