Earth to gain temporary 'mini moon' this autumn
20 Sep 2024

Almost a week later, Earth is set to gain a temporary 'second moon' or 'mini moon.'

A recent study reveals that an asteroid, approximately the size of a city bus, will be drawn into our planet's gravitational field and orbit it for nearly two months.

This celestial body, officially named 2024 PT5, will not crash into Earth but will revolve around it much like our existing Moon.

'Mini moon' to orbit Earth from late September
Orbital journey

The 'mini moon' is expected to accompany Earth from September 29 until November 25, before returning to its original location in an asteroid belt circling the Sun.

Carlos de la Fuente Marcos, a professor at Universidad Complutense de Madrid and lead author of the study, told Space.com that this visitor hails from the Arjuna asteroid belt.

This asteroid belt comprises space rocks that follow orbits very similar to Earth's.

Arjuna belt asteroids can approach Earth closely
Close encounters

Marcos explained that some asteroids in the Arjuna belt can come relatively close to Earth, about 2.8 million miles (4.5 million km) away.

If these asteroids are moving at slower speeds - around 3542km/h - their trajectories become more significantly influenced by Earth's gravity than usual.

"Under these conditions...the object may become a temporary moon of Earth," he said.

NASA's ATLAS program discovered 2024 PT5
Discovery details

The asteroid was first detected on August 7 by the Asteroid Terrestrial-Impact Last Alert System (ATLAS), a program funded by NASA.

ATLAS, which consists of four telescopes, scans the entire night sky every 24 hours and currently monitors around 28,000 asteroids.

The upcoming 'mini moon' is estimated to be about 10 meters long, significantly smaller than Earth's Moon which has a diameter of approximately 3,474km.

'Mini moon' will be difficult to spot
Visibility challenges

Despite its close proximity during its 57-day flyby of Earth, the asteroid will be challenging to observe due to its small size.

According to NASA, 2024 PT5 has an absolute magnitude of 27.593, making it too dim to see even with a telescope.

However, Marcos noted that "the object is well within the brightness range of typical telescopes used by professional astronomers."

Asteroid predicted to return in 2055
Future visits

Scientists predict that the asteroid 'mini moon' will re-enter Earth's orbit again in 2055. This is due to its orbit being similar to that of our planet.

Calculations show that the asteroid will return to circle Earth in 2055.

This is not an unprecedented event as two mini moon events were recorded previously, one in 1981 and 2022.