Thousands of 'City-Killer' Asteroids Undetected by NASA, Earth at Risk

• NASA's head of planetary defense, Dr. Kelly Fast, reveals thousands of potentially destructive 'city-killer' asteroids remain unidentified.
• Approximately 15,000 mid-sized near-Earth objects, at least 140 meters wide, are yet to be located.
• These asteroids could cause significant regional devastation if they impact populated areas.
• Dr. Nancy Chabot warns there's no ready-to-launch spacecraft to deflect a threatening asteroid, despite DART's success.
• Only 40% of objects larger than 140 meters are currently tracked, highlighting detection gaps.