There are questions about its origin, whether it's a rogue asteroid that's been swept up in our gravitational orbit or what. The current prevalent theory is that it's an actual chunk of the moon knocked loose in a giant cosmic fender bender, and is following us through space like the celestial equivalent of those busted turn signal lenses you see lying on the pavement in busy intersections.
In order to settle the mystery, and because it would be a baller accomplishment that would be a feather in their space program's cap, China is planning on sending a probe to retrieve samples from it for study.
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