The moon may look lonely, but it is far from alone. Small asteroids too dim to detect seem to stray into Earth's orbit quite frequently and stay for short periods of time. We may even be able to bring one of these moonlets back to Earth for study. Researchers have long suspected that wandering asteroids might occasionally get snagged by Earth's gravity and become temporary moons, and a few years ago one of these was spotted. Called 2006 RH120, it is a few metres across and wandered into orbit around Earth in July 2006 before drifting off again a year later.
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