Earth to get a new ‘moon’ this month that will orbit our planet for more than 50 days

Earth is about to gain a new cosmic companion as a small asteroid is on course to enter out planet’s orbit for about two months. 

Starting September 29, this ‘mini-moon’ will make a single orbit around Earth before moving on to other regions of the solar system.

This 33-foot-wide asteroid, now named 2024 PT5, was first spotted on August 7 by NASA’s Asteroid Terrestrial-Impact Last Alert System (ATLAS), which may be seen using certain telescopes.

Researchers tracked the ‘mini-moon’s’ trajectory, finding it will briefly take up residence in Earth’s gravitational field until November 25.

Astronomers have created a simulation of what the asteroid looks like in space

When near-Earth objects – asteroids and comets – come within 28 million miles of Earth’s orbit, they follow a horseshoe-shaped path.

The orbit brings the objects closer to our planet at a low relative speed, which temporarily traps in Earth’s orbit like 2024 PT5 will.

Previous research had shown that this space rock does not pose a threat to Earth, but asteroid dynamics researchers from the Complutense University of Madrid suspected that it could temporarily take up residence in Earth’s gravitational field. 

The researchers analyzed data on the asteroid’s size, travel speed and trajectory to approximate its path over the two months following its discovery in August.

The study found that the space rock would enter Earth’s orbit as a mini-moon from September 29 through November 25, circling our planet once over 53 days before escaping back into space. 

Tony Dunn, an amateur astronomer who creates orbit simulations, posted an animation of the path 2024 PT5 will take as it circles our planet. Dunn was not involved in the study. 

Observing the asteroid’s trajectory also allowed researchers to trace it back to its origin. 

They concluded that it most likely came from the Arjuna asteroid belt, a group of many asteroids with orbits around the sun similar to Earth’s.  

Tony Dunn, an amateur astronomer who creates orbit simulations, posted an animation of the path 2024 PT5 will take as it circles our planet

The asteroid will circle our planet once before escaping back into space

The researchers published their findings in the journal Research Notes of the American Astronomical Society.

But Paul Chodas, director of the Center for Near Earth Object Studies at NASA’s Jet Propulsion Laboratory (JPL) who was not involved in the study, told the New York Times that 2024 PT5 may have a different origin story. 

The asteroid’s past movements suggested that it’s ‘possibly a piece of ejecta from an impact on the moon,’ Chodas said, meaning that this mini-moon may be a fragment that broke free from our actual moon. 

Asteroid 2024 PT5 isn’t the first to hang around our planet for a while. In fact, this space rock is following a path similar to an earlier asteroid called 2022 NX1, which became a mini-moon for a brief period in 2022.

But there’s some disagreement over whether this asteroid technically counts as a true mini-moon. To qualify, an asteroid must complete at least one full orbit around Earth. 

‘It certainly won’t complete one full revolution in the Earth-moon system this fall, so I’m not sure I would classify it as a mini-moon,’ Lance Benner, principal investigator of the asteroid radar research program at NASA’s JPL, told the NYT. He was not involved in the study. 

Regardless of how you classify this visiting orbiter, asteroids like 2024 PT5 serve as a reminder of all the celestial traffic whizzing by Earth, and the importance of studying its interactions with our planet.