How NASA’s asteroid hunters are shielding Earth from cosmic threats

Scientists have long kept watch on asteroids that could threaten Earth. Since the late 1900s, tracking these space rocks has become a global priority. The reason is clear: an asteroid just 1 kilometre wide could unleash devastation on a planetary scale.

Efforts to spot and study near-Earth asteroids began in earnest decades ago. By 1990, researchers had already started cataloguing these objects. Since then, the count has risen sharply, with over 40,000 near-Earth asteroids now identified and monitored.

NASA plays a leading role in this work. Its Planetary Defense Coordination Office oversees the search, relying on teams like the Center for Near-Earth Object Studies (CNEOS) and the Jet Propulsion Laboratory (JPL). These groups track the largest and most dangerous asteroids, mapping their orbits to predict future risks. Progress has been steady. Today, NASA estimates that more than 90% of near-Earth objects wider than 1 kilometre have been found. The focus now includes smaller but still hazardous asteroids, ensuring early warnings if any shift toward a collision course. International cooperation has strengthened these defences. Space agencies worldwide share data, improving detection and response strategies. The goal remains the same: to spot threats years or even decades before they near Earth.

The work to guard against asteroid strikes continues. With tens of thousands of objects already tracked, scientists can assess risks more accurately than ever. Still, the search goes on, as even smaller asteroids could pose serious regional dangers if undetected.