Tens of thousands of near-Earth asteroids capable of destroying entire cities remain untracked, and humanity currently has no active system ready to deflect one if it were found to be on a collision course with Earth, space officials have warned.
Speaking at a meeting of the American Association for the Advancement of Science in Phoenix, Arizona, NASA planetary defense officer Kelly Fast said that roughly 25,000 asteroids measuring more than 140 meters in diameter orbit near Earth. Of those, only about 40% have been identified and cataloged.
The sobering assessment comes even as NASA has demonstrated that altering an asteroid’s trajectory is technically possible. In 2022, the agency carried out the Double Asteroid Redirection Test (DART), deliberately slamming a spacecraft into Dimorphos — a small moonlet orbiting a larger asteroid — at approximately 14,000 miles per hour. The impact successfully changed Dimorphos’ orbit, marking the first time humanity intentionally shifted the path of a celestial body.
