Earth is set to gain a “second moon” for about two months this year, thanks to the asteroid 2024 PT5, which was discovered in August 2024 by Nasa’s Asteroid Terrestrial-impact Last Alert System (ATLAS).
Starting from September 29 until November 25, the asteroid will orbit Earth in a horseshoe pattern, mimicking the behavior of a temporary “mini-moon,” according to their study published in Research Notes of the AAs.
Scientists from the Universidad Complutense de Madrid have tracked the asteroid’s orbit for 21 days and determined its future path.
This phenomenon occurs as Earth’s gravity captures small asteroids that temporarily enter its orbit.
Asteroid 2024 PT5 originates from the Arjuna asteroid belt, which consists of bodies that orbit the Sun, much like other Near-Earth Objects (NEOs).
The asteroid will complete its orbit around Earth for 56.6 days before being pulled back into a heliocentric orbit, resuming its path around the Sun.
This isn’t the first time Earth has experienced a “temporary moon.”
In fact, similar occurrences have taken place, such as with asteroid 2020 CD3, which orbited Earth for several years before leaving in 2020, and asteroid 2022 NX1, which orbited Earth in 1981 and 2022 and is expected to return in 2051.
2024 PT5, while small and not visible to the naked eye or even with amateur telescopes, can be observed using more advanced equipment by professional astronomers.
The asteroid’s closest approach to Earth will occur on January 9, 2025, before it finally departs the Earth’s vicinity, not to return until 2055.
What makes this event interesting is the asteroid’s horseshoe orbit.
As it approaches Earth, it is captured in a gravitational tug-of-war that causes it to move in this distinctive shape.
The transition from negative geocentric energy (where the object cannot escape Earth’s pull) to heliocentric energy (where it resumes orbiting the Sun) provides astronomers with valuable data on asteroid dynamics and interactions with planetary gravitational fields.