Until now we thought that only one moon orbited our planet. But he has company – if only for a limited time.
If you look up at the sky at night, you will see the moon when the sky is cloudless. And maybe a few stars. THE moon, not a moon. After all, we only have the one. Or? That’s not entirely correct, because researchers have been observing another object close to Earth for several years: they named it Kamo’oalewa, a Hawaiian term for a celestial body.
However, Kamo’oalewa is too small for a real moon – with a diameter of only around 50 meters. In addition, it does not orbit directly around the earth, but oscillates in a corkscrew-like orbit between the earth and the sun, since it is practically pulled back and forth between the gravitational forces. The scientists puzzled for a long time what this object could be about. It did not resemble an asteroid, such as is often found near the Earth.
What is the mini moon made of?
Asteroids usually glow brightly when irradiated with infrared light. Kamo’oalewa, however, remained dark. This also made it difficult for the researchers to find out more about its composition: it shines “extremely weakly” and is therefore “difficult to observe,” reported the team led by scientist Benjamin Sharkey from the Lunar and Planetary Laboratory in Tucson. Eventually, however, they had an idea.
The team compared the material composition of the mysterious mini-moon to that of the real moon. Lo and behold: the riddle was solved. Apparently, Kamo’oalewa is a fragment of the moon that possibly broke off during an asteroid impact and has been orbiting alone ever since. The researchers estimate that it will keep our moon company for around 300 years. But then the gravitational pull of the earth and the sun will no longer be able to hold it, causing it to be catapulted out of its orbit and fly off into space on lonely paths.