That small asteroid named YR4 is definitely not going to hit the moon

• New observations from the James Webb Space Telescope provided a better understanding of the asteroid's orbit.
• The 300-foot-long asteroid was previously considered a threat to both Earth and the moon.
• The space rock is now projected to safely pass within 13,200 miles of the lunar surface.

Earth has long been deemed safe from a calamitous collision with a certain small asteroid in 2032. The moon, on the other hand, remained under threat for a little while longer.

Finally, though, scientists have been able to conclusively rule out a lunar impact when asteroid 2024 YR4 is in our cosmic neighborhood in a few years.

The moon briefly had a small chance of taking a hit from the asteroid during its close approach in 2032 – prompting one team of scientists to propose simply nuking the space rock.

Now, that extreme plan might not be necessary. New observations from NASA's James Webb Space Telescope that improved our understanding of the orbit of the asteroid, first discovered at the end of 2024, led to good news for our celestial neighbor.

Instead of being a risk to crash into the lunar surface, 2024 YR4 is instead projected to have a close encounter with the moon – passing within a distance that is 18 times closer than the moon is to Earth.

Here's everything to know about the latest observations of asteroid YR4, and its chances of hitting the moon.

What is asteroid 2024 YR4?

Because it's big enough to be deemed a "city killer," asteroid 2024 YR4 became a source of alarm due to the uncommonly high risk it had of colliding with Earth on Dec. 22, 2032.

The space rock was reported Dec. 27, 2024, to the Minor Planet Center, the official authority for observing and reporting new asteroids, comets and other small bodies in the solar system. The object eventually caught the attention of NASA and other astronomers when it rose on the U.S. Space Agency's Sentry Impact Risk Table, which tracks any known asteroids with a non-zero probability of hitting Earth.

Does YR4 pose a threat to Earth?

For a time, it was the only object among more than 37,000 known large space rocks with any chance of hitting Earth anytime soon – with its probability of impact even rising to a record level of 3.1%.

That began to change at the end of February 2025 as more precise observations allowed scientists to effectively winnow down the asteroid's odds of impact to a number so low it might as well be zero.

How big is asteroid 2024 YR4?

Based on observations from the James Webb Space Telescope, scientists know the asteroid's approximate length could reach nearly 300 feet, or about the size of a 15-story building.

Will asteroid 2024 YR4 hit the moon? Scientists rule out possibility

Webb took time to once again take a look at asteroid 2024 YR4 on Feb. 18 and Feb. 26, recording observations that helped determine the space rock will safely pass by the moon in 2032, NASA said in a March 5 blog post.

The asteroid is still expected to come within 13,200 miles of the lunar surface, which by cosmic standards is relatively close. The moon, for instance, is Earth's closest neighbor at 239,000 miles away.

The observations, which have yet to be published in a peer-reviewed study, were led by scientists at the Johns Hopkins Applied Physics Laboratory in Laurel, Maryland.

Odds of YR4 impact with moon rose to above 4%

Webb's initial observations in March 2025 saw the odds of YR4 crashing into the moon rising from the 1.7% figure calculated in February to 3.8%, according to NASA’s Center for Near Earth Object Studies, which tracks objects like asteroids at the agency’s Jet Propulsion Laboratory in California.

While NASA assured that such an impact would not alter the moon's orbit around Earth, it still raised some eyebrows when those odds rose once again to 4.3% after Webb's latest observations were made in May 2025.

The latest observations ruling out a lunar impact are not because the asteroid has shifted along its orbital path, but because scientists now have a better understanding of precisely where the asteroid will be on Dec. 22, 2032.

Eric Lagatta is the Space Connect reporter for the USA TODAY Network. Reach him at [email protected]