Asteroid 2024 YR4 has a small chance of hitting Earth in 2032, but as astronomers make more observations about its trajectory, the odds of a collision are being refined
By Alex Wilkins
18 February 2025 Last updated 20 February 2025
An artist’s impression of what asteroid 2024 YR4 could look like as it approaches Earth in December 2032
NASA
NASA has downgraded the risk of asteroid 2024 YR4 hitting Earth in 2032 to 1.5 per cent, or 1-in-67, down from a high of a 1-in-32 chance, which was the highest odds yet of collision.
Astronomers discovered that the asteroid was barrelling towards Earth in December and it has been a focus of the world’s telescopes and space agencies ever since. As they gather more data on the asteroid’s precise orbit, astronomers have been able to calculate the likelihood of it hitting Earth with greater precision. The asteroid is thought to be between 40 and 90 metres wide and has the potential to release energy equivalent to 7.7 megatonnes of TNT should it hit Earth – enough to destroy a city.
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According to NASA, the odds of collision in 2032 have been edging up from a 1-in-83 chance since it was first spotted. It has since moved to 1-in-67, to 1-in-53, to 1-in-43, to 1-in-38, to 1-in-32 and now falling back to 1-in-67. The European Space Agency has slightly different odds, currently giving the asteroid a 1.38 per cent chance of collision. These changes reflect our growing understanding of the asteroid’s path, rather than necessarily meaning it is any more or less likely to hit Earth.
But we are running out of time to forecast the asteroid’s risk. One issue is that 2024 YR4 will fly behind the sun in April, placing it out of the view of most Earth-based telescopes. That limits how much astronomers can refine their predictions, says Hugh Lewis at the University of Southampton, UK.. “Any observations we can make between now and when it’s out of view will obviously help us to refine the orbit and to make better predictions. That doesn’t necessarily mean that it will go down before April. It could continue to go up, but still ultimately miss us.”
Once the asteroid does fly out of view, it is unlikely that we will gain any more information before it comes into view again in 2028. However, astronomers could comb through past data to uncover previously overlooked observations of the asteroid, which would help refine its trajectory. That process is already being undertaken by the world’s space agencies, says Lewis.