A building-sized asteroid called 2024 YR4 is drifting through the solar system, currently out of sight, but not out of mind. When it returns to view in 2028, scientists hope to know for sure whether it will strike the moon in late 2032. Right now, the odds are small — just over 4 percent — but serious enough to warrant attention.
If YR4 slams into the moon, the blast could be enormous. It would likely carve out a crater nearly a mile wide, tossing up 100 million kilograms of lunar rock and dust. That debris could race toward Earth at incredible speeds, producing a dazzling meteor shower days or weeks later.
For people on the ground, the danger would be virtually zero. Our atmosphere would vaporize the incoming grains of dust before they ever reached the surface. But the same can’t be said for the satellites orbiting overhead, the ones we depend on for GPS, communications, weather forecasting, air travel, banking systems, and more.
Those tiny fragments of moon dust, even just millimeters in size, would be traveling faster than bullets. That’s enough to damage solar panels, antennae, or even knock vulnerable satellites offline. Some experts say it could subject our satellite fleet to a decade’s worth of wear and tear in just a few days.
If astronauts or research stations are on the lunar surface at the time, they could also be at risk. The moon has no atmosphere to buffer the impact. And at this point, there’s no clear plan to deflect YR4 if it’s found to be on a collision course. Unlike Earth-threatening asteroids, lunar impacts aren’t yet part of global planetary defense plans.
The asteroid was only discovered after it had already passed by Earth, hidden in the sun’s glare. That delay has raised fresh concerns about how many other potential threats we might be missing. New space telescopes coming online later this decade may help fill those blind spots. But for now, there’s no way to know for sure whether YR4 is harmless or something more.
And that raises an unsettling question: If scientists ever discovered a much greater threat — something truly catastrophic — would they tell us? Or would they weigh the cost of public panic and societal collapse… and choose to keep it quiet?