By G. Mudalige, Jadetimes Staff
G. Mudalige is a Jadetimes news reporter covering Technology & Innovation
Get ready for a rare cosmic occurrence this autumn — Earth is about to temporarily gain a second moon. According to scientists, a small asteroid will be captured by Earth’s gravitational pull and become a short-term "mini-moon" starting on September 29. Although this new companion will only stay for a couple of months before escaping Earth's gravitational grip, the event is a fascinating example of the dynamic interactions between our planet and nearby space objects.
The asteroid in question, designated 2024 PT5, was first detected by NASA’s Asteroid Terrestrial-Impact Last Alert System (ATLAS) on August 7, 2024. Scientists have since mapped out its trajectory and determined that it will come close enough to Earth to be temporarily trapped in our gravitational field. However, unlike Earth's familiar moon, this new "mini-moon" will be too small and dim to be seen with the naked eye. Only professional telescopes will have the capability to capture images of the asteroid during its brief stay.
2024 PT5 hails from the Arjuna asteroid belt, a collection of space rocks that follow an orbit similar to Earth’s. Objects from this belt occasionally pass close to our planet, sometimes approaching as near as 2.8 million miles (4.5 million kilometers). However, not all asteroids are influenced by Earth's gravity; only those moving at relatively slow speeds, like 2024 PT5, which is traveling at around 2,200 mph (3,540 km/h), can be pulled into orbit. Once captured, 2024 PT5 will briefly orbit Earth before resuming its journey through the solar system. According to Dr. Jennifer Millard, an astronomer and host of the Awesome Astronomy podcast, the asteroid will enter Earth’s orbit on September 29 and is expected to remain until November 25. "It’s not going to complete a full revolution of our planet," Dr. Millard explained in an interview with the BBC’s Today program. "It’s just going to have its orbit altered slightly by our own planet, and then it will continue on its merry way."
While 2024 PT5 will be a temporary visitor, it is not unique. The phenomenon of mini-moons, where small objects are briefly captured by Earth’s gravity, has been observed before. Asteroids of this size are typically 10 meters (32 feet) in diameter—tiny compared to Earth's natural satellite, which boasts a diameter of 3,474 kilometers (2,159 miles). Despite the excitement surrounding Earth’s second moon, 2024 PT5 will remain invisible to the unaided human eye. Because of its small size and dull composition, the asteroid won’t even be visible with standard binoculars or home telescopes. Only professional observatories will be able to capture images of it as it makes its way around the Earth. "Professional telescopes will be able to pick it up," Dr. Millard said. "You’ll be able to look out for lots of wonderful pictures online of this little dot moving past the stars at great speed."
For most people, this means that images of the mini-moon will only be accessible via online channels, with scientists and astronomy enthusiasts sharing photos taken with high-powered equipment. Although it may be disappointing for stargazers hoping to catch a glimpse of this rare event, the prospect of seeing a "second moon" is sure to stir interest worldwide. This cosmic event serves as a reminder of the importance of tracking near-Earth objects (NEOs) and asteroids that pass through our planet's vicinity. ATLAS, the system that first detected 2024 PT5, was designed specifically to identify and monitor objects that could pose a threat to Earth. The system’s early detection of 2024 PT5 allowed scientists to study its orbit and predict its brief capture by Earth's gravity with precision.
Mini-moons like 2024 PT5 are thought to be fairly common, but many go unnoticed because they are small, fast-moving, and difficult to detect. Some, like the asteroid 2022 NX1, have been captured by Earth's gravity more than once. 2022 NX1 became a mini-moon in 1981 and returned again in 2022. The same is expected for 2024 PT5, which scientists predict will return to Earth’s orbit in 2055. Dr. Millard emphasized the significance of these kinds of discoveries. "This story highlights just how busy our solar system is and how much there is out there that we haven’t discovered," she said. "This asteroid was only discovered this year. There are tens of thousands, if not hundreds of thousands, of objects out there that we haven’t found. This highlights the importance of continually monitoring the night sky."
The work done by programs like ATLAS is crucial not only for tracking harmless mini-moons like 2024 PT5 but also for identifying potentially hazardous objects that could pose a danger to our planet. Continuous observation ensures that we have ample warning if a larger, more dangerous asteroid were to come too close for comfort. While 2024 PT5’s brief appearance may seem insignificant compared to the grander scale of cosmic events, it is a reminder of how dynamic and unpredictable our solar system is. Earth’s gravitational pull is strong enough to influence objects millions of miles away, sometimes capturing them temporarily as they pass by.
For scientists, this event provides an opportunity to study the behavior of near-Earth objects and improve their understanding of how small asteroids interact with planets. For the general public, it offers a moment of wonder and curiosity, as Earth briefly hosts a new moon—albeit one that most of us will never see. Although this mini-moon’s visit will be short-lived, it won’t be the last. Scientists are already looking forward to 2024 PT5’s return in 2055, when it will once again give Earth a fleeting second companion in the sky.
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