Earth to Host a “Mini Moon” This Autumn

 

This autumn, Earth will briefly gain a second moon. According to a recent study, an asteroid about the size of a city bus will be captured by Earth's gravity and orbit our planet for roughly two months, becoming a temporary “mini moon.”

The asteroid, expected to arrive on September 29 and stay until November 25, will then return to its orbit around the sun in the asteroid belt. The asteroid belongs to the Arjuna asteroid belt, which contains space rocks with orbits similar to Earth’s, said Carlos de la Fuente Marcos, a professor at Universidad Complutense de Madrid and the study's lead author.

The asteroid will only come within about 2.8 million miles (4.5 million kilometers) of Earth. Due to its slow speed of approximately 2,200 mph (3,540 km/h), Earth’s gravity will significantly influence its path, leading it to become a temporary moon.

Discovered on August 7 by the Asteroid Terrestrial-Impact Last Alert System (Atlas), a NASA-funded program, the asteroid measures about 10 meters long. This is small compared to Earth’s moon, which is around 3,474 km in diameter. The asteroid will be too dim for typical amateur telescopes but visible to professional astronomers’ equipment.

The scientists noted that the asteroid might return to Earth’s orbit again in 2055. Previous instances of mini moons occurred in 1981 and 2022.