Near-Earth Asteroid is a Fragment From the Moon, Say Scientists

Scientists have identified what appears to be a small chunk of the moon that is tracking the Earth's orbit around the Sun. From a report: The asteroid, named Kamo'oalewa, was discovered in 2016 but until now relatively little has been known about it. New observations suggest it could be a fragment from the moon that was thrown into space by an ancient lunar collision. Kamo'oalewa is one of Earth's quasi-satellites, a category of asteroid that orbits the Sun, but remains relatively close to the planet -- in this case about 9m miles away. Despite being close in astronomical terms, the asteroid is about the size of a ferris wheel and about 4m times fainter than the faintest star that can be seen with the naked eye. Consequently, the Earth's most powerful telescopes are needed to make observations. Using the Large Binocular Telescope on Mount Graham in southern Arizona, astronomers found the spectrum of reflected light from Kamo'oalewa closely matched lunar rocks from Nasa's Apollo missions, suggesting it originated from the moon. They had initially compared the light with that reflected off other near-Earth asteroids, but drawn a blank. "I looked through every near-Earth asteroid spectrum we had access to, and nothing matched," said Ben Sharkey, a PhD student at the University of Arizona and the paper's lead author.

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