Oh, so it might be one of ours. Imagine that !

Right this moment, it's not in orbit around the Earth, but it's nearby. And it's going to enter Earth's orbit for a while in 2020 before heading out to circle the sun again.

The initial assumption was that this mysterious blip was an asteroid. The object, termed 2020 SO2 by the Jet Propulsion Laboratory, appears to have been temporarily captured by Earth's gravity. Earth has captured "minimoons" like this before, and scientists have spotted them a couple times in recent years. It's a natural part of our planet's movement through space.

But some observers now say this minimoon might not be natural after all. People built it, they think, back in the 1960s.

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