Earth’s Asteroid Threat: Thousands of ‘City-Killer’ Asteroids Remain Undetected by NASA
Despite years of efforts to map the space environment around Earth, NASA officials warn there remains a significant blind spot in planetary defence: thousands of potentially devastating “city-killer” asteroids that have not yet been identified or tracked.
These asteroids, roughly 140 meters (460 feet) or more in diameter, are large enough that an impact would be catastrophic for a region or metropolitan area, even if it wouldn’t threaten the planet as a whole. According to NASA’s planetary defence estimates, about 15,000 such mid-sized near-Earth objects are still missing from detection radar and ongoing surveys.
The key problem isn’t that these asteroids don’t exist, it’s that many fly in orbits that make them hard to spot with Earth-based telescopes, especially those that don’t reflect much sunlight or approach from the direction of the Sun. Current observation networks are more effective at finding much larger objects and smaller rocks, but mid-range threats are less conspicuous and slip through the gaps.
NASA has already proven it can alter an asteroid’s course, the 2022 DART mission successfully hit a small space rock to slightly change its orbit, but officials emphasize that no spacecraft is currently ready to respond to an imminent threat if one of the undiscovered objects were found to be on a collision path.
Efforts are underway to improve the situation. NASA’s forthcoming Near-Earth Object Surveyor telescope, designed to use infrared imagery from space, aims to locate many of these missing asteroids in the coming decade. But until such systems are fully operational and scanning the skies, the risk from these hidden rocks remains a priority for scientists focused on Earth’s long-term safety.
You may also like
- 'If you ran in New Delhi, you'd win a million votes': Giorgia Meloni recalls 2023 India visit
- Christian man stabbed to death in Pakistan after argument over drinking water: Report
- At this US park, visitors have found over 37,000 diamonds since 1972 and can keep every gem they discover
- Photos: Massive quakes in Venezuela force people onto streets, reduce buildings to rubble
- Firing at Indian restaurant in Canada's Brampton, Goldy Brar gang claims responsibility
These asteroids, roughly 140 meters (460 feet) or more in diameter, are large enough that an impact would be catastrophic for a region or metropolitan area, even if it wouldn’t threaten the planet as a whole. According to NASA’s planetary defence estimates, about 15,000 such mid-sized near-Earth objects are still missing from detection radar and ongoing surveys.
The key problem isn’t that these asteroids don’t exist, it’s that many fly in orbits that make them hard to spot with Earth-based telescopes, especially those that don’t reflect much sunlight or approach from the direction of the Sun. Current observation networks are more effective at finding much larger objects and smaller rocks, but mid-range threats are less conspicuous and slip through the gaps.
NASA has already proven it can alter an asteroid’s course, the 2022 DART mission successfully hit a small space rock to slightly change its orbit, but officials emphasize that no spacecraft is currently ready to respond to an imminent threat if one of the undiscovered objects were found to be on a collision path.
Efforts are underway to improve the situation. NASA’s forthcoming Near-Earth Object Surveyor telescope, designed to use infrared imagery from space, aims to locate many of these missing asteroids in the coming decade. But until such systems are fully operational and scanning the skies, the risk from these hidden rocks remains a priority for scientists focused on Earth’s long-term safety.
More from our partners
Loving Newspoint? Download the app now
