On Sunday, a car-sized asteroid made a record-close pass just 2,950 km from Earth. Experts at NASA's Center for Near-Earth Object Studies didn't detect it until six hours after its flyby.
Measuring 5.5 meters wide by 2 meters long, the space rock—now designated 2020 HQ—raced over Earth's southern hemisphere at over 44,000 km/h. It was spotted by the Palomar Observatory in California only after closest approach. "We didn't see it coming," said Paul Chodas, director of NASA’s Center for Near-Earth Object Studies.
Chodas described the event as the "closest ever recorded," excluding asteroids known to have struck our planet.
Notably, asteroid 2020 JJ—a small van-sized object—had passed undetected just 13,400 km away last May.
Neither object threatened Earth. Our atmosphere would have disintegrated them on impact, creating an airburst equivalent to tens of kilotons of TNT roughly 4 km above the ground.
This incident highlights the critical need for constant sky surveillance. Since 2005, NASA has targeted rocks over 140 meters in diameter. In May 2019, the agency reported identifying fewer than half of the estimated 25,000 such objects in the Solar System.
Addressing this, NASA and ESA launched the DART (Double Asteroid Redirection Test) mission to test asteroid deflection in 2022, targeting binary asteroid (65,803) Didymos, discovered in 1996.
Smaller asteroids remain risky too. In July 2019, a 130-meter object passed within less than 72,400 km of Earth—under 20% of the Earth-Moon distance—spotted only days earlier. An impact could have killed tens of thousands.
Come next year, the Vera C. Rubin Observatory will transform detection, revealing thousands of new asteroids and bolstering planetary defense.
