A new 'mini-moon' comes to Earth this fall

Earth will be hosting a new guest this fall.

No, it's not an alien. It's an asteroid.

The space rock, which has been named “2024 PT5,” has been traveling along its normal path around the sun, but will be temporarily pulled into Earth's gravitational orbit later this month.

The object, which is around 33 feet long, was first spotted by researchers in South Africa, who wrote about it in the journal Research Notes of the American Astronomical Society this month.

Some scientists have described 2024 PT5 as a “mini-moon.”

What is a mini-moon?

In simple terms, a mini-moon is a space object that is temporarily captured in a planet's orbit, as opposed to regular moons, which are permanent fixtures.

The researchers say 2024 PT5 will travel around the Earth in a “horseshoe” path for about two months, from Sept. 29 to Nov. 25.

But there’s some disagreement among scientists about whether 2024 PT5 should be classified as a mini-moon, since it won’t be making a full revolution around the Earth before the sun’s gravity pulls it back onto its normal path.

This is not the first time such a phenomenon has happened. In 2020, astronomers identified another mini-moon, 2020 CD3, which orbited the Earth for over a year.

This also will not be 2024 PT5’s only visit — scientists predict it will be captured again by Earth’s gravity in 2055.

Can we see it?

Unfortunately, 2024 PT5 will not be visible to the naked eye, and home telescopes likely won’t cut it.

"The object is too small and dim for typical amateur telescopes and binoculars," Carlos de la Fuente Marcos, one of the authors of the journal entry describing the asteroid, told Space.com.

“However, the object is well within the brightness range of typical telescopes used by professional astronomers,” Marcos said.

The asteroid was first observed using a telescope from the NASA-funded Asteroid Terrestrial-impact Last Alert System.

Despite that program’s menacing name, scientists say there is no cause for worry and assure that 2024 PT5 is not on a collision course with Earth.