NASA has issued a stark warning regarding the existence of around 15,000 undetected asteroids, each over 140 meters in diameter, that pose a significant threat to Earth. These so-called 'city-killer' asteroids have not been tracked, leading to concerns about a potential catastrophic impact. Kelly Fast, NASA's Acting Planetary Defense Officer, highlighted these dangers during a conference, emphasizing the importance of monitoring such objects to ensure planetary safety.

The agency's alert has sparked fear worldwide, prompting discussions on global preparedness and mitigation strategies. While many might be unaware of the scale of this threat, NASA is actively working on solutions, including the Near-Earth Object Surveyor mission, which aims to enhance detection capabilities. This initiative underscores the critical need for an effective defense system against potential asteroid impacts, especially given the high number of untracked objects that could cause extensive damage.

The alarm raised by NASA highlights a significant gap in planetary defense, urging not only technological advancements but also international cooperation to address these threats. As the potential for catastrophic events looms with so many unidentified objects, the urgency for a comprehensive approach to monitoring and defense has never been more pronounced, affecting global safety and future explorations into our solar system.