Asteroid 2024 YR4 Could Hit Earth in 7 Years: What We Know So Far
A newly discovered asteroid, 2024 YR4, has a 2% chance of colliding with Earth in 2032, according to astronomers. While the odds are low, scientists are closely monitoring this space rock, which is estimated to be between 131 and 295 feet (40 to 90 meters) wide—roughly the size of a large building. Although it’s far smaller than the "planet-killer" asteroid that wiped out the dinosaurs 66 million years ago, an impact from 2024 YR4 could still cause significant regional damage.
Discovery and Tracking Efforts
The asteroid was first spotted on December 27, 2024, by the Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope in Chile. Since then, observatories worldwide, including the Very Large Telescope in Chile and Hawaii’s Pan-STARRS system, have been tracking its movement. However, due to its distance—currently over 30 million miles (48 million kilometers) away—scientists have struggled to refine its size and trajectory using reflected sunlight alone.
To address this, astronomers plan to use the James Webb Space Telescope (JWST) to measure the asteroid’s heat emissions in infrared light. Observations are set for early March and May, with the goal of determining its exact size, orbit, and potential threat level. If Webb’s data reduces uncertainty, the risk of collision may drop to zero. But if 2024 YR4 fades from view before conclusive results are obtained, it will remain on the risk list until it reappears in June 2028.
Potential Impact and Historical Context
If 2024 YR4 were to hit Earth, the effects would depend on its size and composition. At its largest estimate, the asteroid could cause blast damage up to 50 kilometers (31 miles) from the impact site, similar to the Tunguska event of 1908. That incident, caused by a 30-meter-wide asteroid, flattened 2,150 square kilometers (830 square miles) of Siberian forest. More recently, in 2013, a 20-meter asteroid exploded over Chelyabinsk, Russia, injuring over 1,000 people and damaging thousands of buildings.
While asteroids of this size strike Earth every few thousand years, smaller ones enter the atmosphere more frequently, often disintegrating as harmless fireballs. Larger impacts, though rare, pose catastrophic risks, making early detection critical.
The Challenge of Finding Near-Earth Objects
Objects like 2024 YR4 are notoriously difficult to detect because they’re relatively small, dark, and fast-moving. Scientists estimate there are around 600,000 near-Earth objects in this size range, but only about 2% (12,000) have been identified so far. Larry Denneau, co-principal investigator of ATLAS, emphasized the importance of continuous sky surveys: “There are still many large ones out there that we haven’t found yet, which is why we are continuously monitoring the whole sky.”
HawaiÊ»i’s telescopes play a key role in planetary defense, offering unparalleled accuracy in spotting and tracking asteroids. “Thanks to our prime location and advanced technology, we can evaluate potential threats and figure out the best ways to respond,” said Doug Simons, director of the University of HawaiÊ»i’s Institute for Astronomy.
Moving Forward
For now, astronomers remain cautiously optimistic. With tools like the James Webb Space Telescope joining the effort, humanity is better equipped to assess and mitigate potential threats. Whether 2024 YR4 poses a real danger or fades into obscurity, its discovery highlights the ongoing need for vigilance in protecting our planet from cosmic hazards.
As scientists gather more data, the world watches and waits, hoping for reassurance that Earth remains safe—for now.