Scientists have discovered that a small portion of the moon is being used to track the Earth's orbit around it.
Although the asteroid was named Kamooalewa was discovered in 2016, very little information has been available about it. It could be a fragment of the moon that was sent into space in an ancient lunar collision, according to new observations.
Kamooalewa, one of Earth's quasisatellites is an asteroid that orbits Sun but is still relatively close to planet, in this case, about 9m miles.
Although it is very close in astronomical terms, the Asteroid is approximately the same size as a ferris wheel. It is also about 4m smaller than the faintest star visible with the naked eye. To observe the asteroid, you will need to use the most powerful telescopes on Earth.
Astronomers used the Large Binocular Telescope at Mount Graham in Arizona to observe the spectrum of reflected sunlight from Kamooalewa. It closely matched the lunar rocks obtained by Nasa's Apollo missions. This suggests that it came from the moon. The light was initially compared with the light reflected off near-Earth asteroids. But, they were unable to find a match.
"I looked through every near Earth asteroid spectrum that we had access too, and nothing matched," stated Ben Sharkey, a University of Arizona PhD student and lead author of the paper.
The telescope was shut down during the coronavirus pandemic in April 2020, so Kamooalewa was not possible to be observed. However, the team finally found the last piece of the puzzle in 2021.
Sharkey stated, "This spring we received much-needed follow-up observations, and went, Wow, it is real!'" Sharkey added. It's much easier to explain the moon than with other ideas.
Also, the observations showed that Kamooalewa was in an unusual orbit. This is not typical for objects that have drifted towards Earth through the asteroid belt between Mars & Jupiter.
Because there are no known asteroids of lunar origin, the team is unsure how this piece of moon became lost in space. They narrowed the timeframe to include the violent event occurring between 100,000 and 500 year ago.
Professor Stephen Lowry, an Astronomer at the University of Kent said that while the evidence is not conclusive, it was strong enough to suggest that Kamooalewa could indeed have been a fragment of a collisional event such as a lunar collision.
These findings were published in Nature Communications Earth and Environment.