A new “mini moon” is coming to Earth this fall: NPR

Earth will welcome a new guest this fall.

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

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

The approximately 10-meter-long object was first discovered by researchers in South Africa who wrote about it in the journal American Astronomical Society Research Notes this month.

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

What is a mini moon?

In simple terms, a minimoon is a space object that is temporarily trapped in a planet's orbit, unlike normal moons, which are permanent fixed points.

The researchers say 2024 PT5 will travel around the Earth on a “horseshoe track” for about two months, from September 29 to November 25.

However, there is disagreement among scientists about whether 2024 PT5 should be classified as a minimoon because it will not complete a complete revolution around Earth before the Sun's gravity pulls it back into its normal orbit.

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

This won't be PT5's only visit in 2024 either – scientists predict it will be captured by Earth's gravity again in 2055.

Can we see it?

Unfortunately, 2024 PT5 won't be visible to the naked eye, and home telescopes probably won't make it.

“The object is too small and too 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 NASA-funded Asteroid Terrestrial-Impact Last Alert System telescope.

Despite the program's ominous name, scientists say there is no cause for concern and assure that 2024 PT5 is not on a collision course with Earth.