Risk of 2032 Asteroid Impact Reduced: Key Details You Should Know

Asteroid 2024 YR4 recently made headlines after NASA estimated a 1-in-32 chance of impact in 2032—the highest probability ever recorded for a hazardous-sized asteroid. Fortunately, new observations have since cut that risk in half.

Discovered in late December, the asteroid passed Earth at roughly twice the Moon’s distance. Based on observations, its size is estimated to be between 40 and 90 meters (130 to 295 feet) wide.

As with all near-Earth objects (NEOs), scientists calculated 2024 YR4’s future trajectory. While it’s currently moving away from Earth, it’s expected to make another close pass in December 2028.

Potential Impact Triggers Concern

However, its next approach caused concern. NASA’s Center for Near-Earth Object Studies (CNEOS) identified a small but real chance of impact in December 2032. By late January 2025, that risk exceeded 1%, triggering a report to the International Asteroid Warning Network (IAWN).

Further observations increased the estimated probability, with ESA’s Near-Earth Object Coordination Centre assigning a 2.8% chance of impact, while CNEOS briefly raised it to 3.1%—the highest ever recorded for an asteroid of this size or larger.

With the Full Moon waning and darker skies improving visibility, astronomers resumed tracking the asteroid using ground-based telescopes. New data allowed CNEOS to lower the impact probability to 1.5%.

While this is reassuring—given that the initial risk was already low—astronomers will continue monitoring 2024 YR4 to refine its trajectory. The likelihood of impact could drop to zero, as often happens, or, in rare cases, increase again.

Tracking an Asteroid’s Path

When astronomers discover an asteroid, they track its motion over time to map out its trajectory. Initially, predictions resemble a narrowing cone—short-term positions are highly accurate, but further into the future, the range of possible paths expands.

If Earth falls within that range, the asteroid has a non-zero chance of impact. As additional observations refine its course, the probability of collision adjusts accordingly.

In most cases, an asteroid that initially appears to threaten Earth will see its risk drop to zero as refined calculations rule out an impact. However, in some instances, updated data can increase the odds—eliminating miss trajectories while impact paths take up a larger portion of the remaining possibilities.

This pattern played out with asteroid 2024 YR4, explaining why its estimated risk initially rose after discovery. Fortunately, the probability has now decreased from a peak of 3.1% to 1.5%, though further observations could push it in either direction.

That said, probability alone isn’t the only factor NASA and other agencies consider when assessing an asteroid’s impact risk.

Assessing Impact Risk

The Torino scale rates asteroid impact risk based on probability and potential destruction, ranking objects from 0 to 10. Small meteors under 20 m (66 ft) default to 0, while a 10 signifies a near-certain, catastrophic impact by an asteroid at least 1 km (0.6 miles) wide.

Asteroid 2024 YR4 currently holds a 3—the second-highest Torino rating ever. Dubbed the “city-killer,” it could devastate an urban area, as even its smallest estimated size is twice that of the 2013 Chelyabinsk meteor, which injured nearly 1,500 people. Traveling at 17 km (10.5 miles) per second, it could cause a powerful airburst and shockwave.

Despite its concerning potential, YR4 is far from a global threat. A planet-wide disaster would require an asteroid at least 1 km wide, while YR4’s maximum estimated size is 80 m. The only asteroid to rank higher on the Torino scale was 99942 Apophis, which briefly reached a 4 before further observations ruled out any risk for the next century.

Astronomers will continue tracking asteroid 2024 YR4 to refine its trajectory, with the James Webb Space Telescope set to observe it in March. Its 2028 close pass may also offer a clearer opportunity to calculate its future orbit.

The most probable outcome is that additional data will allow astronomers to downgrade its threat level to 0. But if the risk remains, there’s still time to take action.

NASA’s 2022 DART mission demonstrated that a spacecraft impact could alter an asteroid’s path. The test successfully changed the orbit of a small asteroid by 32 minutes, proving that such a method could be viable for planetary defense.

With seven years to prepare, a mission to deflect YR4 could be feasible—no Hollywood-style heroics required.

Read the original article on: New Atlas

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