Imagine waking up to the news that a massive asteroid, capable of leveling an entire city, is hurtling toward Earth—and there’s nothing we can do to stop it. This isn’t the plot of a Hollywood blockbuster; it’s a chilling reality that keeps NASA scientist Kelly Fast up at night. But here’s where it gets controversial: while we’ve mapped the paths of larger asteroids and shrug off the smaller ones that burn up in our atmosphere, there’s a hidden threat lurking in the shadows—mid-sized asteroids, dubbed ‘city killers,’ that are too small to detect easily but large enough to cause catastrophic damage. And this is the part most people miss: there are roughly 15,000 of these undetected asteroids near Earth, and we’ve only located about 40% of them.
Fast, a planetary defense officer at NASA, recently shared her concerns at the American Association for the Advancement of Science (AAAS) in Phoenix, Arizona. She explained that these mid-sized asteroids, measuring around 500 feet, are particularly dangerous because they don’t reflect enough sunlight to be spotted by even the most advanced telescopes. Instead, they silently accompany Earth in its orbit around the Sun, making them nearly invisible until it’s too late. To put it in perspective, these ‘interstellar in-betweeners’ could cause ‘regional damage’—destroying cities, triggering tsunamis, or unleashing firestorms.
Here’s the kicker: even if we detect one of these city killers, our current defenses are woefully inadequate. In 2022, NASA’s DART mission successfully nudged a small asteroid off course, but replicating this feat with a larger, faster-moving asteroid would be exponentially harder. As Nancy Chabot, the DART mission leader, bluntly put it, ‘We don’t have a deflector craft sitting around ready to go.’ Worse, space agencies lack the funding to keep such defenses on standby, leaving us dangerously unprepared.
Scientists are racing to address this gap with the Near-Earth Object Surveyor space telescope, set to launch next year. This innovative tool uses thermal signatures to detect dark asteroids and comets that have evaded our current systems. But even with this technology, the question remains: What do we do once we spot one? Blowing it up with nukes, as suggested for the notorious asteroid YR4 (which has a 4% chance of hitting the Moon in 2032), sounds like a scene from Armageddon—but is it feasible? Or are we simply delaying the inevitable?
And this is where you come in: Should we prioritize funding for asteroid deflection technologies, even if it means diverting resources from other scientific endeavors? Or is this a risk we’re willing to take, hoping these city killers never cross our path? Let’s spark a conversation—because the next asteroid could be closer than we think.
