Remember that asteroid, 2024 YR4, that briefly worried scientists about hitting Earth? Good news: updated tracking confirms the Earth risk is extremely low, essentially zero for 2032. But here’s the twist: its shifted path now puts the Moon at a significantly higher risk of impact on December 22, 2032. New research suggests this isn’t just a potential sky show – a lunar impact could pose real challenges for our activities in space.
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The key takeaways? Earth is safe from asteroid 2024 YR4 in 2032, but the Moon might not be, with a growing chance of impact. Such an event would be a rare spectacle, but it also highlights previously underestimated risks to satellites and future lunar missions.
The Story So Far: Dodging Earth
When asteroid 2024 YR4 was first spotted in late 2024, initial calculations showed a concerning 1 percent chance of it hitting Earth in 2032. As astronomers gathered more data, that chance briefly climbed, making it, for a short time, appear to be one of the most concerning objects tracked.
However, this is exactly why scientists constantly monitor Near-Earth Objects (NEOs). More observations mean more precise orbital paths. As predicted by the astronomy community, with additional tracking data, the probability of Earth impact plummeted dramatically, now estimated at a tiny 0.004 percent. Earth is clear.
A New Target: The Moon
While the threat to Earth receded, the improved orbital calculations revealed a shift in the asteroid’s potential path. As planetary scientist Dr. Andrew Rivkin noted, the orbit moved away from Earth, but closer to the Moon.
What was initially a lower chance of hitting our natural satellite began to increase. Earlier estimates put the Moon impact risk around 3.8 percent. Following further precise observations, including data from NASA’s James Webb Space Telescope (JWST) and analysis by NASA’s Center for Near-Earth Object Studies (CNEOS) at JPL, the official probability of asteroid 2024 YR4 striking the Moon on December 22, 2032, has been updated to 4.3 percent. On that date, it’s expected to pass incredibly close to the Moon – within about 0.00007 Astronomical Units (AU). To put that in perspective, 1 AU is the distance between the Earth and the Sun, so this is closer than a cosmic whisper.
Diagram illustrating the orbital uncertainty of asteroid 2024 YR4 showing potential paths close to Earth and the Moon in 2032
What Happens If It Hits?
Unlike a potential Earth impact, which could cause significant regional or even global issues depending on size, an asteroid hitting the Moon doesn’t pose a direct threat to life on our planet. However, it would be a remarkable event.
According to a new study led by Paul Wiegert at the University of Western Ontario, an impact by 2024 YR4 could release energy equivalent to roughly 6.5 megatons of TNT. This would excavate a new crater on the lunar surface, estimated to be about 1 kilometer (0.62 miles) in diameter. Statistically, this would likely be the largest impact on the Moon in about 5,000 years – a truly rare event on a human historical timescale.
More Than Just a Spectacle: The Space Debris Risk
While the visual spectacle is exciting – potentially even causing new, harmless lunar meteorites to arrive on Earth – the study highlights a less obvious but potentially significant consequence: ejected material.
The impact could blast an estimated 10⁸ kilograms of lunar rock and dust into space. Crucially, some of this material would be ejected with enough speed to escape the Moon’s weak gravity entirely. Where does it go? Into cis-lunar space (the region around the Earth and Moon) and even into orbits where our satellites reside.
Imagine a sudden, dense swarm of tiny rocks, ranging from millimeters to centimeters in size, filling a region of space that is currently relatively clean. The study warns that this could expose satellites in near-Earth orbit to years, potentially even a decade, of increased impact risk from these lunar fragments. At its peak, the instantaneous flux of hazardous-sized particles could be 10 to 1,000 times higher than the normal background.
This finding suggests that our understanding of planetary defense needs to extend beyond just protecting Earth’s surface to also considering the safety of our vital space infrastructure, including satellites and missions like the Lunar Gateway or future surface operations on the Moon.
What’s Next?
Right now, asteroid 2024 YR4 is too far and faint for current telescopes to observe, making it impossible to refine its orbit further or pinpoint a potential impact location on the Moon (or confirm a miss).
However, the asteroid’s orbit around the Sun will bring it back into Earth’s vicinity in 2028. This window will allow astronomers and NASA’s CNEOS team to take new observations. These will provide crucial data to significantly improve the precision of the asteroid’s path and either confirm a collision course with the Moon or rule it out entirely.
While the probability is still below 5 percent, the potential consequences for space operations mean scientists are taking this possibility seriously. As researchers noted, agencies like NASA are already considering potential responses if the risk is confirmed in 2028.
A lunar impact in 2032 remains a relatively low probability event, but the potential for both a spectacular celestial display and, importantly, a significant new hazard to our space assets makes asteroid 2024 YR4 a key object of interest for planetary scientists and space agencies alike. We’ll get a much clearer picture in 2028.
