A new, unreviewed study suggests that if the 60-metre-wide asteroid 2024 YR4 crashes into the Moon in 2032, the resulting colossal explosion could send debris hurtling towards Earth, potentially endangering satellites and creating a spectacular meteor shower.
Earlier this year, there were brief concerns that asteroid 2024 YR4, large enough to devastate a city, might directly impact Earth on December 22, 2032.
While subsequent observations definitively ruled out a direct hit on our planet, data from the James Webb Space Telescope in May indicates that the odds of it striking the Moon have risen to 4.3 per cent.
Lead study author Paul Wiegert of Canada’s University of Western Ontario, who conducted the first estimation of such a collision’s effects on Earth, stated that this would be the largest asteroid to hit the Moon in approximately 5,000 years.
The impact would release energy comparable to a major nuclear explosion, ejecting up to 100 million kilograms of material from the Moon’s surface, according to simulations. If the asteroid strikes the Earth-facing side of the Moon (a roughly 50 per cent chance), up to 10 per cent of this debris could be pulled into Earth’s gravity in the days that follow.
While Earth’s atmosphere would protect the surface from the millimetre- to centimetre-sized lunar rocks, Wiegert warned that these fast-moving meteors could destroy satellites.
He estimated that over 1,000 times the normal number of meteors could threaten Earth’s satellites in the days after impact, likening a centimetre-sized rock travelling at tens of thousands of metres per second to “a lot like a bullet.”
Conversely, those on the ground would be treated to a “spectacular” meteor shower lighting up the night sky.
Wiegert emphasised that the current odds of a direct hit on the near side of the Moon remain at just two per cent.
The asteroid is not expected to be visible again until 2028, delaying further detailed observations. However, if a direct collision becomes likely, Wiegert believes humanity would have enough time to plan a mission to potentially deflect the asteroid, calling it “a good target” for a planetary defence test, similar to NASA’s DART mission in 2022.
He cautioned that attempting to deflect it if it’s already too close to Earth could be “dangerous.”
The study has been submitted to the Astrophysical Journal Letters.
