Is Earth about to get a new moon? Yes, but not for long

Earth will soon have a second moon, but it will be nothing like the one we're accustomed to seeing in the night sky.

The new "mini-moon" will be asteroid 2024 PT5, a space rock discovered earlier this year. It will be temporarily captured by Earth's gravity before continuing its journey through the solar system.

Measuring just 33 feet across, the asteroid will follow a horseshoe-like path around the Earth and will be a mini-moon from Sept. 29 until Nov. 25, according to a study published by the American Astronomical Society.

A visualization of a small asteroid above the Earth. (Getty Images)

After its brief gravitational dance with the planet, it will not return to Earth's neighborhood until 2055.

Most people will not be able to see the temporary moon due to its small size. To catch a glimpse of the asteroid, stargazers will need a telescope much larger than the typical backyard variety. Even still, it will be difficult to detect during its brief encounter with the Earth.

It is uncommon for Earth to have a mini-moon such as asteroid PT5, but it is not unheard of.

"Earth can regularly capture asteroids from the Near-Earth object (NEO) population and pull them into orbit, making them mini-moons," according to research by Carlos de la Fuente Marcos and Raúl de la Fuente Marcos.

Some mini-moons have hung around much longer than the one making a pit stop at Earth this autumn. One asteroid, known as 2006 RH120, remained gravitationally bound to the Earth for one year, starting in July 2006. Another asteroid, known as 2020 CD3, was a mini-moon for several years before escaping Earth's gravitational tug.