2006 RH120 was the first reliably documented example of a temporary moon.
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2006 RH120, as it became known, turned out to be a tiny asteroid just a few metres across—a natural satellite like the Moon. It was captured by Earth’s gravity in September 2006 and orbited us until June 2007 when it wandered off into the Solar System in search of a more interesting neighbour.
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“At any given time, there should be at least one natural Earth satellite of 1-meter diameter orbiting the Earth,” say Granvik and co. These objects should hang around for about 10 months and make about three revolutions of the planet.
