On September 29, 2024, a rare astronomical event will take place as Earth gains a temporary “second Moon” for about two months. The asteroid, named 2024 PT5, was discovered by NASA on August 7, 2024, and originates from the Arjuna asteroid belt. It will circle Earth until November 25, 2024, before returning to its original orbit.
Measuring just 33 feet (10 meters) in diameter, 2024 PT5 is much smaller than the actual Moon, making it difficult to see with the naked eye. Despite its tiny size, the asteroid’s orbit around Earth has led many to call it a “second Moon.”
According to a study from the American Astronomical Society, Earth can periodically capture asteroids from the Near-Earth Object (NEO) population, drawing them into its orbit to become what scientists term “mini-moons.”
“Objects in the Arjuna asteroid belt are part of the near-Earth object population of asteroids and comets,” explained Carlos de la Fuente Marcos, professor at Universidad Complutense de Madrid and lead author of the research. “Under these conditions, the geocentric energy of the object may grow negative, and the object may become a temporary moon of Earth.”
Marcos further clarified that mini-moons can be categorized into two types: those that orbit Earth for a year or longer, and those that stay for shorter periods, like 2024 PT5, which will only be visible for a couple of months.
While this phenomenon will be difficult to observe directly, scientists are eager to study the asteroid further during its brief visit. It is expected to return to Earth’s orbit in 2055.
