Kamoʻoalewa, a Piece of the Moon
A small asteroid that loops around the Earth like a second moon may be a chunk of our own Moon, knocked off by an ancient impact.
What was reported
In 2016, the Pan-STARRS telescope on Haleakalā, in Hawaii, discovered a small asteroid, about 40 to 100 metres across, that follows a strange path. It orbits the Sun, but in a way that makes it seem to circle the Earth, as a 'quasi-satellite'. It was named Kamoʻoalewa, a Hawaiian name referring to an oscillating celestial object.
In 2021, astronomers found that light reflected from it looks very like Moon rock, weathered by space, and unlike most asteroids.
Explanations offered
Scientists think Kamoʻoalewa may have been blasted off the Moon by an impact, perhaps the one that made the crater Giordano Bruno on the far side. China's Tianwen-2 mission is planned to visit it and bring back samples, which should settle the question.
- When
- Discovered in 2016
- Where
- Haleakalā Observatory, Maui, Hawaii, USA
- Witnesses
- Astronomers using the Pan-STARRS telescope
- Status
- Probably confirmed
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.
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