A New Moon(let) for Planet Earth

It’s called Kamo’oalewa (or 2016 HO3), and it orbits the Sun along with Earth and the Moon. Earth and planetary scientists suspect it was once part of the Moon! What is it? Well, officially, it’s a “quasi-satellite” or a “moonlet” and it joins four other quasi-satellites found around our planet.

Other quasi-satellites are suspected to be asteroids captured by Earth’s gravitational pull. But in examining the spectrum of light bouncing off Kamo’oalewa (diameter 164 feet), Benjamin Sharkey and Vishnu Reddy of the University of Arizona found a red spectrum that matches Moon rocks returned by Apollo astronauts. This has led Sharkey, Reddy, and their team to suspect that it was chipped off the Moon and flung into orbit by a massive impact long ago. They published their analysis in the journal Communications Earth & Environment.

How to confirm this? China has a mission in development to retrieve a piece of Kamo’oalewa and bring it to Earth for an up-close analysis sometime in the mid-2020s. But they better hurry! Sharkey estimates that, given its unstable orbit, Kamo’oalewa will one day break free of Earth’s gravitational hold and will hurl off into the dark void of space.