Every once in a while, our planet captures a “mini-moon,” a tiny asteroid that hangs out in our orbit for a bit before venturing back into the depths of space. New research suggests these small, temporary natural satellites carry tremendous scientific and commercial opportunities—but the trick will be in finding them.
Twelve years ago, astronomers with the Catalina Sky Survey detected our planet’s first and only known natural satellite other than the Moon. Named 2006 RH120, it measures about 6 to 10 feet in length (2-3 meters), and it temporarily enters Earth’s orbit every 20 years or so, before returning to its ordinary orbit around the Sun. Surprisingly, and despite steady improvements to telescope technology, it remains the only known mini-moon, or TCO (temporarily captured orbiter).
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