Space agencies are talking a lot these days about sending people to the Moon – and even setting up permanent bases there. But you might not want to be on the Moon seven years from today. A space rock that’s half the size of an NBA arena has a slight chance of slamming into the Moon.

Asteroid 2024 YR4 was discovered last year, two days after Christmas, when the asteroid had flown just half a million miles from Earth.

Early observations gave it more than a three percent chance of hitting Earth on December 22nd, 2032. As astronomers tracked it longer, they ruled out that chance. Instead, they calculated that it’ll pass about 7,000 miles from the Moon. But there’s a 45-thousand-mile margin of error. So there’s a better than four percent chance that it will hit the Moon.

2024 YR4 is so far away right now that we can’t see it. It won’t return to view until 2028. Once it reappears, astronomers will refine their calculations. That probably will rule out the chance of an impact. But for now, we can’t know for sure.

The asteroid is about 200 feet in diameter. That’s about the size of the asteroid that gouged the famous meteor crater in Arizona. So an impact on the Moon probably would form a big crater. Debris from the impact could travel hundreds of miles – cosmic missiles crashing across much of the Moon.

Script by Damond Benningfield