Moon rocks blasted off the lunar surface could become near-Earth asteroids.
Scientists have discovered that moon rocks blasted off the lunar surface by impacts from asteroids and comets could become near-Earth asteroids, or NEAs. This finding, published in the journal Nature Geoscience on October 24, 2023, could help scientists better understand the origin and evolution of NEAs, which are a potential threat to Earth.
Previous research had shown that Kamo'oalewa, a small NEA, is likely a piece of the moon. However, it was unclear how moon rocks could be ejected into space and become NEAs.
The new study, led by Renu Malhotra, a planetary scientist at the University of Arizona, suggests that a process called "lunar resonance ejection" could be responsible. In this process, a large impact on the moon could blast rocks into space. These rocks could then enter a resonant orbit with the moon, meaning that their orbital periods are in a simple ratio to the moon's orbital period. This resonance could then gradually perturb the rocks' orbits, eventually causing them to be ejected from the moon's gravitational sphere of influence.
Malhotra and her team used computer simulations to show that lunar resonance ejection is a feasible mechanism for delivering moon rocks to near-Earth space. They also estimated that this process could eject up to 100 tons of lunar material into near-Earth space each year.
The finding that moon rocks could become NEAs has several implications. First, it suggests that the moon may be a more important source of NEAs than previously thought. Second, it suggests that NEAs may have a wider range of compositions than previously thought, including some that are similar to the moon. Third, it could help scientists better understand the formation and evolution of NEAs, which could help them to better assess the risk posed by these objects to Earth.
Future research could focus on identifying more lunar fragments among Earth asteroids. Scientists could also use computer simulations to better understand the dynamics of lunar resonance ejection and to estimate the total amount of lunar material that has been ejected into near-Earth space over time.