Earth To Get A Temporary Second Moon, Scientists Say

CALIFORNIA — Earth will soon have a temporary second moon.

A small asteroid will become a "mini moon" for nearly two months starting Sunday, according to a study published in the journal Research Notes of the American Astronomical Society.

Researchers said the tiny asteroid, named 2024 PT5, will temporarily orbit Earth before returning to an asteroid belt revolving around the sun. Scientists discovered the object Aug. 7 using the Asteroid Terrestrial-impact Last Alert System in Sutherland, South Africa, according to the study published this month.

"The object that is going to pay us a visit belongs to the Arjuna asteroid belt, a secondary asteroid belt made of space rocks that follow orbits very similar to that of Earth at an average distance to the sun of about 93 million miles," Carlos de la Fuente Marcos, the study's lead author and Universidad Complutense de Madrid professor, told Space.com. "Objects in the Arjuna asteroid belt are part of the near-Earth object population of asteroids and comets."

Near-Earth objects, also known as NEOs, have come close to the planet in the past. There were mini moon events in 1981 and 2022, according to the study.

"Near-Earth objects that follow horseshoe paths, and approach our planet at close range and low relative velocity, may undergo mini-moon events in which their geocentric energy becomes negative for hours, days or months, but without completing one revolution around Earth while bound," the study said. "An example of NEO experiencing such a temporarily captured flyby is 2022 NX1, which was a short-lived mini-moon in 1981 and 2022."

This year's mini moon is expected to orbit Earth from Sept. 29 to Nov. 25, according to the study.

Asteroid 2024 PT5 won't be visible to most skywatchers, however.

Marcos told Space.com that professional-grade telescopes with a diameter of at least 30 inches and a charge coupled-device or complementary metal oxide semiconductor detector are needed to observe the object.

"The object is too small and dim for typical amateur telescopes and binoculars," Marcos said. "However, the object is well within the brightness range of typical telescopes used by professional astronomers."