From 3753 Cruithne to 2024 Discoveries: a History of Earth's Temporary Moons

A detailed look at From 3753 Cruithne to 2024 Discoveries: a History of Earth's Temporary Moons, including essential background.

Q1: Does Earth officially have more than one moon?
A1: No. The International Astronomical Union (IAU) only recognizes one permanent natural satellite for Earth: the Moon. Objects like 2024 PT5 or 2020 CD3 are categorized as near-Earth asteroids undergoing temporary gravitational capture or co-orbital resonance.

Q2: Why don't temporary mini-moons crash into Earth?
A2: Their orbital paths are shaped by high relative velocities and shifting gravitational pulls from the Sun, Earth, and Moon. Instead of decaying into the atmosphere, their chaotic trajectories loop around Earth before flinging them back out into independent solar orbits.

Q3: How often does Earth capture a temporary moon?
A3: Gravitational simulations suggest that at least one meter-sized asteroid orbits Earth as a temporary satellite at any given time. Most are too small, faint, and fast-moving to be picked up by existing telescopes, though next-generation observatories detect them with increasing regularity.