Chance of a devastating asteroid impact briefly spiked in 2025

The chances of a devastating asteroid impact briefly increased in 2025, after astronomers discovered a building-sized asteroid hurtling toward Earth.

The asteroid, named 2024 YR4, was first detected by astronomers in late December 2024 and its width was estimated to be between 40 and 90 meters. Its possible trajectories through our solar system fell through a narrow window that contained Earth, with astronomers estimating at the time that it had a 1 in 83 chance of hitting the planet in 2032.

As they made more detailed observations of the asteroid’s trajectory over the first months of 2025, astronomers calculated increasingly likely chances of impact, reaching its most perilous level of 1 in 32 chance in early February.

If the hypothetical impact had occurred near a city, the consequences would have been devastating, releasing the equivalent of megatons of TNT. The asteroid was deemed dangerous enough to be briefly designated as a 3 on the Turin rating system out of 10 of likely impact consequences, in which 0 means there will be no consequences and 10 means it will cause a global catastrophe. It also prompted several United Nations-affiliated agencies to take additional steps, such as coordinating global telescope observation campaigns and meeting to decide whether an asteroid deflection mission might be necessary.

During this period, global space agencies met and coordinated regularly to compare their observations and try to better understand the asteroid. “2024 YR4 has been a great teacher for us,” says Richard Moissl of the European Space Agency (ESA). “It was excellent training that improved our [asteroid detection] methods and our understanding of the whole issue.

By February 20, astronomers had refined 2024 YR4’s orbit enough to exclude Earth almost entirely from the window through which the asteroid would pass, and the ESA quickly reduced the chance of impact to 1 chance in 625, or 0.16 percent. A few weeks later, NASA and ESA announced that there was no chance of impact. “It’s not seen as a threat to the Earth,” says Moissl.

However, astronomers could not rule out a possible impact on the Moon, with the risk currently at around 4% for 2032. “If the Moon were to collide, it would be a wonderful opportunity to learn more about the impact process and witness it from a safe distance,” says Gareth Collins of Imperial College London.

Scientists began to calculate possible consequences of an impact on the Moon, such as an asteroid launching a shower of satellite-destroying shells toward Earth, as well as whether a diversion mission would be possible and what might be the most effective strategy to employ, from firing small satellites at the asteroid to destroying it with a nuclear bomb. “We would have to do this very carefully, so as not to transform an impact on the Moon into an impact on the Earth,” explains Moissl.

Our imprecise figure of a 4% chance of an impact on the Moon is currently not high enough to prompt global space agencies to seriously plan a mission. This figure is also unlikely to change anytime soon, because 2024 YR4 is currently behind the sun and therefore not visible to telescopes – and it will not appear again until 2028. However, we will have a rare chance to observe it in February 2026 with the James Webb Space Telescope, due to its unique observation point in orbit around Earth. The data from these observations will be our last realistic chance to decide whether we want to launch some sort of mission to visit or deflect the asteroid, Moissl says, because designing a mission to an asteroid can take many years.

Total solar eclipse cruise 2027: Spain and Morocco

Embark on an extraordinary journey aboard the Douglas Mawson, a state-of-the-art expedition ship, to witness the longest total solar eclipse of this century, taking place on August 2, 2027.