Discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS), a NASA-funded monitoring program, 2024 PT5 was first spotted in August this year by an observatory in South Africa. This small asteroid originates from the Arjuna asteroid belt, a group of near-Earth objects that travel in orbits similar to our own planet’s.
Using 21 days of meticulous tracking, scientists from the Complutense University of Madrid charted its future trajectory. Their findings, published in the Research Notes of the American Astronomical Society, confirmed that Earth’s gravitational pull will temporarily capture the asteroid. In this short window, 2024 PT5 will become what astronomers call a “mini-moon.”
Not the First Mini-Moon, But a Unique One
While Earth has hosted temporary moons in the past, not all asteroid visitors stick around long enough to complete even a partial orbit. In rare cases, however, an asteroid is drawn into a stable enough trajectory to circle our planet.
One such example is 2020 CD3, a mini-moon that orbited Earth for several years before breaking free in 2020. Similarly, 2022 NX1 briefly became a mini-moon in both 1981 and 2022, with plans to revisit Earth’s orbit in 2051. What makes 2024 PT5 particularly intriguing is its size, as it’s larger than many of its predecessors. And if that wasn’t enough, it’s already expected to return to Earth’s orbit around 2055.
The Orbital Dance of 2024 PT5
So, how does this temporary moon manage to stick around? Earth’s gravitational field plays a crucial role. As 2024 PT5 approaches, it will experience a phenomenon called negative geocentric energy, which essentially traps the asteroid in an elongated, horseshoe-shaped orbit around the planet. This gravitational embrace will hold the asteroid for around two months before it breaks free, regaining positive heliocentric energy and resuming its journey around the Sun.
Even after leaving Earth’s orbit, 2024 PT5 will linger nearby for several months. Its closest approach is expected on January 9, 2025, after which it will definitively drift away—at least until its predicted return decades from now.
Can You See It?
For those hoping to catch a glimpse of this cosmic visitor, there’s a slight catch. Unfortunately, 2024 PT5 won’t be visible to the naked eye or even most amateur telescopes. Only professional astronomers equipped with powerful instruments will be able to observe the mini-moon in action. But while it might not make for a visual spectacle, its presence is a compelling reminder of the fascinating choreography of celestial objects constantly at play above us.
A Rare Reminder of Earth’s Place in the Cosmos
While we often think of Earth’s single, familiar moon as a constant, events like the arrival of 2024 PT5 remind us of the ever-changing nature of our solar system. This temporary companion is more than just a curiosity; it’s an opportunity for scientists to study how celestial bodies interact with Earth’s gravitational pull, offering insights into the behavior of near-Earth objects.
So while most of us won’t witness 2024 PT5 firsthand, its brief stay around our planet will be one for the scientific books—another extraordinary chapter in humanity’s ongoing exploration of the universe.