Scientists Help Characterize Earth’s Second Known Minimoon

IMAGE: International Gemini Observatory image of 2020 CD3 (center, point source) obtained with the 8-meter Gemini North telescope on Hawaii’s Maunakea. The image combines three images each obtained using different filters to produce this color composite. 2020 CD3 remains stationary in the image since it was being tracked by the telescope as it appears to move relative to the background stars, which appear trailed due to the object’s motion. CREDIT: International Gemini Observatory/NOIRLab/NSF/AURA/G. Fedorets

From Mars, we move even closer to home and take a look at Earth’s latest minimoon, a newly discovered asteroid with the designation 2020 CD3. Astronomers used the Lowell Discovery Telescope to analyze this second minimoon, and their work is published in The Astronomical Journal.

A minimoon is a tiny asteroid that gets captured by Earth’s gravity, orbits our planet for a while, and then gets flung back out into the solar system. The first minimoon discovered here was found back in 2006.

CD3 was discovered early this year, and scientists quickly rallied to observe and understand our new satellite while they had the chance. Measurements indicate that CD3 is a natural satellite, made of silicate, about 1-1.5 meters in diameter and that it came within ...