In our orbit there’s not just us and the Moon, but also the Apollo asteroids, including this one:
According to a new analysis, a chunk of rock that hangs out near Earth’s orbital path along the Sun seems to be made of the same material as the Moon, suggesting that it broke off at some point to be flung into space. But how, and when, remains a mystery.
The rock is named 469219 Kamoʻoalewa, and astronomers already found it interesting before this latest development.
The object belongs to a class of asteroids known as the Apollo asteroids, which more or less share Earth’s orbit around the Sun; but Kamoʻoalewa is also what is known as a quasi-satellite, staying near Earth over long periods and multiple orbits.
Kamoʻoalewa is small, just 46 to 58 meters or so in diameter (150 to 190 feet), and can only be seen in Earth’s sky for a few weeks every April. It wasn’t discovered until 2016, and learning more about it hasn’t been easy.
In this most recent effort to learn more, researchers made use of one of the most powerful telescopes on Earth, the Large Binocular Telescope at Mount Graham International Observatory. In 2017, they obtained observations that included the asteroid‘s spectrum – the distinct pattern generated by the way Kamoʻoalewa reflects light from the Sun. [ScienceAlert]
Maybe the coolest part, though, is the name:
It was named Kamoʻoalewa, a Hawaiian word that refers to an oscillating celestial object. [Wikipedia]
No pics, though.
