Get ready for an extraordinary celestial event this autumn, as Earth is set to temporarily gain a second moon. According to a study published in the Research Notes of the American Astronomical Society (RNAAS), a small asteroid, named 2024 PT5, will be captured by Earth’s gravitational pull, becoming a “mini-moon” from 29th September to 25th November.
This space visitor hails from the Arjuna asteroid belt, a region of space with asteroids that follow orbits similar to Earth’s. Asteroids from this belt occasionally approach our planet, sometimes getting as close as 2.8 million miles (4.5 million km). In this case, 2024 PT5, a 32-foot-long (10m) asteroid, will be pulled into Earth’s orbit because of its relatively slow speed—around 2,200mph (3,540km/h)—allowing our planet’s gravitational field to temporarily trap it.
While it might sound exciting to have a second moon, this mini-moon won’t be visible to the naked eye. Its small size and composition of dull rock mean it won’t be easy to spot, even with binoculars or amateur telescopes. Only professional-grade telescopes will be able to capture images of this small dot moving swiftly across the sky. Dr Jennifer Millard, an astronomer, highlighted the fleeting nature of this event, stating that the asteroid will not complete a full revolution around Earth, but will have its orbit subtly altered before continuing its journey through space.
This isn’t the first time Earth has gained a temporary mini-moon, and it likely won’t be the last. Some asteroids, like 2022 NX1, have even made repeat visits, briefly orbiting Earth in both 1981 and 2022. Similarly, scientists predict that 2024 PT5 will return in 2055, giving us another chance to witness this rare event.
The discovery of 2024 PT5, made by NASA’s Asteroid Terrestrial-Impact Last Alert System (ATLAS) on 7th August, serves as a reminder of how active and dynamic our solar system is. As Dr Millard pointed out, “There are tens of thousands, if not hundreds of thousands, of objects out there that we haven’t discovered yet.” This underscores the importance of continually monitoring the night sky to track these celestial bodies.
