NASA Updates Earth Impact Risk Assessment for City-Killer Asteroid, Raises Alert Again

NASA Raises 2032 Asteroid Impact Risk: What We Know

NASA has upgraded the chances of asteroid 2024 YR4, dubbed a “city-killer,” colliding with Earth on December 22, 2032. The new risk assessment shows a 3.1% probability (1 in 32 odds)—up from 1.2%—based on recent observations.

Asteroid 2024 YR4: Key Details

• Size: Estimated between 130–300 feet wide.
• Impact Force: If it enters Earth’s atmosphere, it could explode midair with the energy of 8 megatons of TNT—over 500 times Hiroshima’s atomic bomb.
• Composition: Likely rocky, not metallic.

Artist’s depiction of an asteroid nearing Earth (Credit: NASA/JPL-Caltech)

While not a global threat like the dinosaur-killing asteroid, 2024 YR4’s potential airburst or surface impact could devastate a city. “This is not a crisis, but a rare event requiring monitoring,” said Richard Moissl, ESA’s planetary defense chief.

Historical Context

• Tunguska Event (1908): A similar-sized asteroid exploded over Siberia, flattening 830 square miles of forest.
• Apophis (2004): Formerly the highest-risk asteroid, with a 2.7% impact chance ruled out by 2029 flyby data.

Detection & Monitoring
Discovered in December 2024 by Chile’s El Sauce Observatory, YR4 topped NASA’s Sentry Risk List. The James Webb Space Telescope (JWST) will study its composition as it orbits near Jupiter until its 2028 approach.

Impact Scenarios

• Airburst: Exploding midair could cause widespread damage without a crater.
• Surface Impact: A direct hit would release debris at 10+ miles per second—faster than the ISS’s orbit speed.

Hypothetical impact zones include the Pacific, South America, Africa, and Asia (Credit: ESA)

Expert Reassurance
Astronomers caution against panic. “Initial risk percentages often fluctuate,” noted Bruce Betts of The Planetary Society. If odds exceed 10%, global agencies like the International Asteroid Warning Network (IAWN) would trigger emergency protocols.

Next Steps
NASA continues refining YR4’s trajectory. Enhanced tracking aims to either confirm the risk or eliminate it entirely—as seen with Apophis.

This condensed report highlights critical facts; stay updated via NASA’s Planetary Defense Coordination Office.