NASA spotted a big asteroid that may hit Earth — what you should know

It’s actually good news that NASA spotted a sizable asteroid with a (small) chance of hitting Earth in 2032.

It means our asteroid-sleuthing telescopes are working.

“These things come through on a regular basis,” Jason Steffen, an astronomer at the University of Nevada, Las Vegas, told Mashable. “The fact that we’re seeing something around a decade into the future shows the improved technology that’s been deployed to watch for these asteroids.”

The Asteroid Terrestrial-impact Last Alert System — a global network of telescopes funded by NASA to find Earth-threatening objects — spotted the asteroid 2024 YR4 in December 2024. Early observations of the asteroid’s behavior and trajectory show it has a 1.4 percent chance of an Earth impact in the year 2032 (as of Jan. 30, 2025). The number you might not hear is the asteroid also has a 98.6 percent chance of missing our planet.

But it’s still notable. “ Currently, no other known large asteroids have an impact probability above 1 percent,” NASA explained.

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It’s a sizable asteroid

The reason why asteroid 2024 YR4 has captured astronomers’ attention is because it’s estimated to be 130 to 300 feet wide. That’s certainly not a “planet-killer” asteroid, like the half-mile wide or larger space rocks that can cause global devastation. (The asteroid that wiped out non-avian dinosaurs was around six miles wide and came from beyond Jupiter.)

Yet an asteroid some 130 to 300 feet across can be, depending on its composition, regionally devastating. The asteroid that hit Arizona 50,000 years ago and created the 600-foot-deep “Meteor Crater” was 100 to 170 feet (30 to 50 meters) across.

“A similar-size impact event today could destroy a city the size of Kansas City,” David Kring, an impact cratering expert at the Lunar and Planetary Institute, explained in a NASA blog.

Expect impact information to change

In the coming years, space agencies like NASA and European Space Agency, along with organizations like the International Asteroid Warning Network (IAWN), will continue to track and characterize asteroid 2024 YR4. It’s likelihood of impacting Earth could change. Eventually, the risk could potentially even disappear. We don’t yet know.

“My colleagues and I have been paying attention to potentially-Earth-impacting asteroid 2024 YR4, which Torino 1 initially and now is Torino 3 (‘merits attention by astronomers’),” posted Heidi B. Hammel, a planetary astronomer, referencing the Torino Scale that categorizes an object’s hazard level. “Impact predict is 2032, but more data may reduce probability to zero.” (The Torino Scale goes up to 10.)

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The impact prediction will change because astronomers don’t yet have an accurate enough grasp of the asteroid’s characteristics nor location. “If you want to make predictions about where it’ll be in the future, you have to know its location conditions very well,” explained Steffen. “A few meters off is a lot.” (Just a small unknown or error in a prediction amplifies, profoundly changing the prediction.)

You can stay tuned: NASA’s Center for Near Earth Object Studies provides updates on asteroids like 2024 YR4.

NASA has not released an impact warning

NASA has never issued an asteroid impact warning.

The agency is just releasing information of public and scientific interest. In the still unlikely event of an impact, any potential regional effects remain far from certain. For example, over 70 percent of Earth’s surface is covered in ocean; a non-coastal landing could cause little harm. (That’s why the International Space Station will be disposed into the Pacific Ocean.)

Asteroid scientists will need to better characterize 2024 YR4 to provide any useful warning, should one ever be needed. “You need to know what’s coming, when it’s coming, and how hard it’s going to hit,” Eric Christensen, the director of the near-Earth object-seeking Catalina Sky Survey in Arizona, previously told Mashable. If the asteroid is rocky or rubble-like, it could largely break up in Earth’s atmosphere, but still create powerful atmospheric explosions. If it’s a metallic asteroid, it could pummel the surface and create a giant crater.

“You need to know what’s coming, when it’s coming, and how hard it’s going to hit.”

In 2032, if an impact affecting the globe becomes certain or too risky, NASA would provide warning notifications to the White House, Congress, and government agencies.

“Will it detonate in Earth’s atmosphere, or make it closer to the ground?” explained NASA’s former Planetary Defense Officer, Lindley Johnson, in a previous interview. “We can advise leadership as to what might be faced should the asteroid impact the planet.”

For instance, although we can’t currently redirect an asteroid or stop an impact, we can direct people to evacuate an area.

The risks of an asteroid impact

Here are today’s general risks from asteroids or comets both tiny and very large. Importantly, even relatively small rocks can still be threatening, as the surprise 56-foot (17-meter) rock that exploded over Russia and blew out people’s windows in 2013 proved.

• Every single day about 100 tons of dust and sand-sized particles fall through Earth’s atmosphere and promptly burn up.

• Every year, on average, an “automobile-sized asteroid” plummets through our sky and explodes, according to NASA.

• Impacts by objects around 460 feet (140 meters wide) in diameter occur every 10,000 to 20,000 years.

• A “dinosaur-killing” impact from a rock perhaps a half-mile across or larger happens on 100-million-year timescales.