Earth is about to welcome a new “mini-moon” as asteroid 2024 PT5 enters our planet’s gravitational pull later this month. The recently discovered asteroid, which will orbit Earth from September 29 to November 25, will not stick around for long. After its brief visit, the space rock will return to its regular orbit around the sun. Despite its fleeting presence, this event offers astronomers a unique opportunity to study the behaviors and trajectories of such temporary mini-moons.
A Brief Stay in Earth’s Orbit
Asteroid 2024 PT5, estimated to be around 37 feet (11 meters) in diameter, will be temporarily captured by Earth’s gravity, making it the latest in a series of mini-moons that occasionally orbit the planet. First detected by NASA’s ATLAS (Asteroid Terrestrial-impact Last Alert System) observatory in South Africa, the asteroid’s journey has sparked interest among astronomers.
Carlos de la Fuente Marcos, a researcher from the Complutense University of Madrid and the lead author of a study on 2024 PT5, explains that such events are relatively rare. Mini-moons can complete one or more orbits around Earth or, like 2024 PT5, make only a partial pass before escaping our planet’s gravity. These short-capture events can occur a few times each decade, while long-capture events are much less frequent.
A Mini-Moon with No Danger of Collision
Unlike more dramatic asteroid events, like the Chelyabinsk meteor that exploded over Russia in 2013, 2024 PT5 poses no threat of colliding with Earth. The asteroid will orbit about 2.6 million miles (4.2 million kilometers) from Earth—roughly 10 times the distance between Earth and the moon. De la Fuente Marcos reassures that 2024 PT5 won’t pose any danger to the planet, either now or in the near future.
Mini-moons like 2024 PT5 are drawn into Earth’s gravity due to their speed and trajectory, but the conditions for capture are precise. Robert Jedicke, an expert from the University of Hawaii’s Institute for Astronomy, who was not involved in the study, noted that most asteroids approach Earth too quickly or at the wrong angle to be captured. However, sometimes the combined forces of the solar system’s objects allow a slow-moving asteroid to be temporarily trapped.
Asteroids that become mini-moons can originate from various regions, including the Arjuna asteroid belt, a collection of small asteroids with orbits similar to Earth’s. Asteroid 2024 PT5 is believed to have come from this belt. Some mini-moons may also come from the main asteroid belt between Mars and Jupiter, or even be fragments of the moon’s surface, ejected by past asteroid impacts.
Jedicke added that mini-moons could help scientists better understand how craters form on the lunar surface and how material is launched from the moon into space. He estimates that there is always at least one dishwasher-sized mini-moon orbiting the Earth-Moon system, but these objects are notoriously difficult to detect.
At roughly 37 feet in diameter, 2024 PT5 is the largest captured object discovered to date. As it travels along its horseshoe-shaped path, it offers scientists a valuable opportunity to study the behaviors of these elusive space objects.
The Future of Asteroid 2024 PT5
After spending 56.6 days orbiting Earth, asteroid 2024 PT5 will be pulled back into its normal heliocentric orbit by the sun’s gravity. However, this won’t be Earth’s last encounter with this particular space rock. According to astronomers, 2024 PT5 is expected to make a close flyby of Earth on January 9, 2025, passing just 1.1 million miles (1.7 million kilometers) away. The asteroid is predicted to return as a mini-moon for a brief period in November 2055 and again in early 2084.
In the meantime, de la Fuente Marcos and his team plan to gather more data on 2024 PT5 using advanced telescopes in Spain’s Canary Islands. While amateur astronomers won’t be able to observe the asteroid due to its small size and dim appearance, professional astronomers are eager to learn more about the characteristics and movements of this temporary visitor.
Asteroid 2024 PT5’s brief stay as Earth’s mini-moon offers a unique opportunity for scientists to study the dynamics of space rocks temporarily captured by our planet’s gravity. Though its time with Earth is short, its trajectory and characteristics provide valuable insights into the behaviors of asteroids in our solar system. With future flybys expected, 2024 PT5 will likely continue to captivate astronomers for decades to come.
