Earth to Temporarily Capture a “Second Moon” This Fall: A Rare Cosmic Event

Scientists say Earth is about to gain a “second moon” for a short period, so get ready for a cosmic surprise this fall. According to researchers, Earth is on the verge of capturing a small asteroid with its gravity, turning it into a temporary “mini-moon.”

This celestial visitor will arrive on September 29 and stay for a few months before breaking free from Earth’s gravity again.

Unfortunately, this second moon will be too small and dim to be seen with the naked eye—unless you have a professional telescope. The asteroid was first detected by NASA’s Asteroid Terrestrial-impact Last Alert System (ATLAS) on August 7.

Scientists detailed its trajectory in a study published in the *Research Notes of the American Astronomical Society*.

The asteroid, referred to by scientists as 2024 PT5, originates from the Arjuna asteroid group, which consists of rocks that follow a path similar to Earth’s orbit.

Occasionally, some of these asteroids come relatively close to our planet, approaching within 2.8 million miles (4.5 million kilometers).

According to the researchers involved in the study, if an asteroid like this moves at a relatively slow speed of about 2,200 miles per hour (3,540 km/h), Earth’s gravitational field can exert enough influence to temporarily capture it.

And that’s exactly what’s about to happen. Starting this weekend, this small asteroid will spend roughly two months in Earth’s orbit. Dr. Jennifer Millard, an astronomer and host of *Awesome Astronomy*, told the BBC’s *Today* program that the asteroid will enter orbit on September 29 and is expected to leave on November 25.

“It won’t make a complete orbit around our planet,” she said. “Instead, its path will change slightly, just twisting a bit due to our planet before continuing on its merry way.”

The asteroid is about 32 feet (10 meters) long, which is tiny compared to Earth’s moon, which has a diameter of about 2,159 miles (3,474 kilometers).

Due to its small size and dull, rocky composition, it won’t be visible to people on Earth, even with binoculars or a home telescope.

Dr. Millard mentioned that “specialized telescopes will be able to pick it up. So, you can expect to see plenty of amazing images online of this little dot zooming through the stars.”

Mini-moons have been spotted before, and it’s believed that many others have passed by unnoticed.

Some even make repeat visits, like the asteroid 2022 NX1, which became a mini-moon in 1981 and again in 2022.

So, don’t worry if you miss this event—scientists predict that 2024 PT5 will return to Earth’s orbit again in 2055.

“This story highlights just how busy our solar system is and how many asteroids we haven’t yet discovered,” said Dr. Millard. “There are tens of thousands, if not hundreds of thousands, of objects we have yet to discover, so I believe this highlights the importance of continuously monitoring the night sky and discovering all these things.”