An asteroid is going to hit the moon. Here’s how scientists plan to destroy it

When a space rock the size of a football field heads in our direction, even slim odds are enough to make scientists sit up and pay attention. Asteroid 2024 YR4 is not expected to hit Earth, but it still carries a small chance of colliding with the Moon. And that is a scenario no one wants to take lightly.

Last year, astronomers warned that asteroid 2024 YR4 could strike Earth in 2032. That fear has been set aside, but the threat is not entirely gone. Current estimates suggest there is about a four per cent chance of the asteroid hitting the Moon instead. A lunar collision might seem harmless, but it could scatter clouds of debris into low-Earth orbit. That could endanger satellites and even astronauts aboard the International Space Station.

Researchers from NASA and several American institutions have been studying how best to deal with the risk. Their findings, published on the preprint server arXiv and awaiting peer review, suggest that blowing up the asteroid may be safer than trying to deflect it.

Deflection has been tested before. In 2022, NASA's DART mission nudged a small asteroid moonlet off its path with success. But repeating that feat with 2024 YR4 is far more complicated. Its mass is uncertain, with estimates ranging from 33 million to 930 million kilograms. With such margins of error, a poorly calculated deflection could accidentally push the asteroid towards Earth.

That is why scientists now lean towards destruction. They propose either striking it hard enough to shatter it or using a nuclear device to break it apart. Both methods remain untested, but there is time to prepare.

Most likely, 2024 YR4 will miss the Moon altogether. Yet its looming presence serves as a reminder: preparing for the improbable may one day save us from the inevitable.