Scientists map thousands of ways ‘city-killer’ asteroid 2024 YR4 could hit the moon, resulting in an explosion as bright as Venus

Building-sized asteroid 2024 YR4 is unlikely to collide with the moon in 2032, but a new study predicts that the asteroid could produce thousands of impact flashes and extreme meteor storms, putting on a spectacular show for sky-watchers.

The space rock, which is about 200 feet (60 meters) wide, or about the size of a 15-story building, was discovered on December 27, 2024. It briefly gained notoriety in February 2025. Astronomers have calculated that the probability of an asteroid of similar size or larger hitting Earth is the highest ever. This chance was as high as 3.1%, but more detailed estimates of the asteroid’s orbit ruled out the possibility that the rock would hit Earth during its approach on December 22, 2032.

But NASA says there’s still a 4.3% chance that YR4 will hit the moon instead in 2024. A 2025 study notes that such an impact would release energy equivalent to 6.5 million tons of TNT, making it the largest lunar impact recorded in modern times.

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Yifei Zhao, a postdoctoral researcher at the University of California, Santa Cruz, was intrigued by this possible effect. He told Live Science in an email that he and his colleagues found this to be a “rare ‘natural experiment,’ a predictable small-body collision with scientifically rich and operationally relevant signatures.” As a result, the researchers wanted to evaluate all possible outcomes.

10,000 collisions

To do this, scientists created a computer model of the solar system, including the asteroid, all the planets, Earth’s moon, and the sun, and simulated the path that YR4 would take at high speed through the inner solar system in 2024.

By tweaking the space rock’s trajectory, the team created 10,000 such simulations and used them to chart the areas of the moon most likely to be impacted. The researchers also simulated the actual collision process over a 500-second time interval using a separate, more detailed set of simulations. The researchers tracked the object’s path as it escaped the moon’s gravity and modeled different possible scenarios for impact debris.

Their simulation results, which are available on the arXiv preprint server and have not yet been peer-reviewed, suggest that the asteroid will likely impact the moon somewhere within a range of about 1,900 miles (3,000 kilometers) in length. The predicted impact corridor is just north of the Moon’s Tycho crater. According to the Planetary Society, when viewed from Earth’s northern hemisphere (and vice versa from the southern hemisphere), it will be along the lower half of the moon.

An explosion as bright as Venus

Even more amazingly, this collision produces a star-like flash of magnitude between -2.5 and -3, making it almost as bright as Venus in the night sky. The flash lasts between 200 and 300 seconds (3 to 5 minutes), but should be reliably visible for at least 10 seconds “if the background conditions are bright enough for the flash to be reliably perceptible,” lead author Yifan He, a researcher at China’s Tsinghua University, told Live Science in an email.

If a collision were to occur, the predicted impact time would be 10:19 a.m. ET (15:19 UTC), meaning a flash would be visible in parts of the world where the moon rose. This would make East Asia, Oceania, Hawaii, and western North America ideal locations for viewing.

However, there is a catch. On the day of the predicted impact, 70% of the moon will be illuminated. The impact flash would only be visible to unaided observers if the asteroid impacted an unlit area of ​​the Moon. He and Yixuan Wu, a researcher at Tsinghua University and second author of the study, estimate that there is only a 2.85% chance that asteroid 2024 YR4 will hit the moon.

Still, regardless of the location of the impact, the flash is detectable with amateur telescopes. It is also possible that another scenario will occur. The impact would lift many moon rocks, which would rain down on the moon’s surface, potentially causing thousands of flashes. However, the flashes from these secondary impacts will not be as bright as the primary impact and will probably be more difficult to see without equipment.

Additionally, the study predicts that the impact could send up to 220 million pounds (100 million kilograms) of lunar rock toward Earth. These would cause what Wu calls a “super meteor storm,” an extreme meteor shower that would be noticeable between two and 100 days after the impact. Although YR4’s impact on the moon in 2024 is still quite uncertain, Wu is excited about the future. “If this scenario were to materialize, it would be a milestone for planetary science, and the Earth-Moon system would become a major stage for testing our understanding of asteroid collisions,” she told Live Science via email.

in context

in context

brandon specter

Space and physics editor

Since 2024 YR4, Earth is safe, but asteroid research provides some of the best planetary defense practices we’ve had to date. When this asteroid was first discovered and deemed a potential risk, telescopes around the world focused on observing it, and even the James Webb Space Telescope used its limited discretionary time to observe it.

These rapid and thorough observations narrowed down the asteroid’s size and orbit, ensuring it would not collide with Earth. We’re not always so lucky, but the more we practice tracking near-Earth asteroids, the better prepared we will be if a real threat from space emerges.