Asteroid 2024 YR4: from a potential threat to a negligible risk.

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The asteroid 2024 YR4 has now been reclassified to level zero on the Torino Scale, which indicates "no risk," as additional tracking of its orbital path has reduced the likelihood of it intersecting with Earth to below the threshold of 1 in 1000.

An illustration shoes asteroid 2024 YR4 making a close passage of Earth (Image credit: Robert Lea (created with Canva))

It's time to take a breath; the asteroid that once posed the largest threat to Earth in recorded history is now virtually zero chance of impacting our planet. The probability of asteroid 2024 YR4 colliding with Earth has dropped to zero thanks to new data collected on Sunday, February 23.

Asteroid 2024 YR4 was discovered in December 2024 and quickly topped NASA's risk list, where its chance of hitting Earth at one point was 1 in 32. This raised it to level 3 on the Torino Scale, a system used since 1999 to classify potential impact events with Earth.

Level 3, which falls within the yellow range of the Torino Scale, is described as: "A close encounter worthy of astronomer attention. Current calculations give a 1% or greater chance of a potentially hazardous impact."

Richard Binzel, a professor of planetary sciences at the Massachusetts Institute of Technology (MIT) and developer of the Torino Scale, stated to Space.com: "NASA's Center for Near Earth Object Studies (CNEOS) now lists a 0.00005 (0.005%) chance of YR4 impacting Earth in 2024, or 1 in 20,000 for a close pass in 2032." He added, "This means the chance of impact is zero, folks!"

This aligns with the second part of the description of level 3 on the Torino Scale, which states: "Likely, new telescopic observations will lead to a reclassification to level 0. Public and government officials deserve attention if the encounter is less than a decade away." Binzel continued, "Asteroid 2024 YR4 has now been reclassified to level zero on the Torino Scale, which indicates 'no risk,' as additional tracking of its orbital path has reduced the likelihood of it intersecting with Earth to below the threshold of 1 in 1000. 1 in 1000 is the threshold established for lowering the classification to level 0 for any body smaller than 100 meters; YR4 is estimated to be about 164 feet (50 meters) in size."

As news organizations worldwide continue to show interest in asteroid 2024 YR4, Space.com has been consulting asteroid hunter David Rankin from the Catalina Sky Survey, who found images of the space rock in archive data collected before its official discovery.

Asteroid 2024 YR4 from potential threat to zero risk

From the beginning, Rankin expected the odds of asteroid 2024 YR4 colliding with Earth to initially rise before dropping sharply. He explained where this ambiguity arises when tracking the asteroid's path:

"Imagine you hold a stick a few feet long. If you move the stick in your hand by a fraction of an inch, you won’t notice any movement at the other end," says Rankin. "Now imagine the stick is millions of miles long. Moving your hand by a fraction of an inch will cause radical changes at the other end."

This "fraction of an inch" movement is similar to the slight uncertainty in the asteroid's positional measurements through telescope imaging of the asteroid, which arises from small timing errors and minor positional inaccuracies.

As more observations are collected, these uncertainties start to fade.

Although asteroid 2024 YR4 is now likely to fade from public interest, Binzel highlighted some points we all should remember from the evolution of this story.

"Astronomer at MIT remarked, 'As 2024 YR4 fades from the news, I think there’s a broader context that is the most important news. A body the size of YR4 passes through the Earth and Moon neighborhood multiple times a year without causing damage.

"The YR4 episode is just the beginning for astronomers gaining the ability to see these bodies before they reach our region."

Binzel added that, like 2024 YR4, some newly discovered asteroids will initially have uncertain distances, but follow-up observations will clarify their paths.

"But just like with YR4, with a little time and careful follow-up, we will be able to rule out any risk entirely," he added. "This means that low-ranked bodies on the Torino Scale are likely to be a common event, exciting for space enthusiasts and astronomers to follow, but not particularly newsworthy."

Although 2024 YR4 poses no threat, it will still have significant scientific impact when it passes by Earth in 2028 and again in 2032.

On December 17, the asteroid will come within 5 million miles of Earth. Then, on December 22, 2032, asteroid 2024 YR4 will pass within just 167,000 miles of our planet. To put that into perspective, the Moon is about 238,855 miles away from us.

While the general public can sleep soundly knowing that asteroid 2024 YR4 will not strike Earth and unleash widespread devastation, scientists will relish the opportunity to study this space rock in detail. Binzel concluded:

"Instead of causing concern for anyone, by finding these existing bodies and determining their orbits, we become more confident in our knowledge that any large-sized asteroid is unlikely to surprise us."

Writer: Robert Lea

Robert Lea is a science journalist in the UK, whose articles have appeared in Physics World, New Scientist, Astronomy Magazine, All About Space, Newsweek, and ZME Science. He also writes about science communication for Elsevier and the European Journal of Physics. Rob has a bachelor's degree in physics and astronomy from the Open University in the UK. You can follow him on Twitter @sciencef1rst.

Image Information:

Orbit of 2024 YR4 as calculated on February 24, 2025 (Image credit: NASA JPL/CNEOS)

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