Astronomers log 40,000th near-Earth asteroid as space agency warns of rising detection pace

ISTANBUL

The European Space Agency (ESA) said Thursday that astronomers have identified the 40,000th near-Earth asteroid (NEA), a milestone the agency says underscores both “our planet’s vulnerability” and the rapid progress of planetary-defense research.

The NEA catalogue passed 40,000 in November 2025, with 10,000 detected in the past three years alone, according to ESA.

NEAs are rocky remnants from the Solar System’s formation whose orbits bring them within about 27.96 million miles (45 million kilometers) of Earth. While the first, Eros, was discovered in 1898, ESA said discoveries accelerated only after dedicated survey telescopes came online in the 1990s.

“The number of discoveries is rising exponentially, from one thousand at the beginning of the century to 15,000 in 2016 and 30,000 in 2022,” said Luca Conversi, manager of ESA’s Near-Earth Object Coordination Centre (NEOCC). “As the next generation of telescopes enter operation, we expect the number of known NEAs to continue to grow at an even higher pace.”

ESA pointed to two major drivers of that expected surge: the newly inaugurated Vera C. Rubin Observatory in Chile, projected to detect tens of thousands of additional NEAs, and ESA’s Flyeye telescopes, designed to spot objects that elude current surveys.

'Most are tiny' with 'no meaningful danger'

Once an NEA is identified, astronomers model its orbit decades or centuries into the future. ESA’s NEOCC continually updates these risk assessments.

Nearly 2,000 NEAs carry a non-zero chance of striking Earth within the next century, the agency said, but most are small and pose no meaningful threat. Larger, kilometer-scale asteroids -- the ones capable of global destruction -- are “the easiest to spot” and are mostly already catalogued.

The greater challenge now, ESA said, lies in detecting the harder-to-see objects between 100 and 300 meters in size, which could cause severe regional damage. Current estimates suggest only about 30% of these have been found.

No threat 'for foreseeable future'

ESA said none of the 40,000 known NEAs are on course to hit Earth “for the foreseeable future,” but stressed the need for continued preparedness.

The agency’s Hera spacecraft is en route to the asteroid Dimorphos to study the aftermath of NASA’s 2022 DART impact -- work intended to turn asteroid deflection into a reliable planetary-defense method.

ESA is also developing the Ramses mission to accompany the asteroid Apophis during its unusually close yet safe approach in 2029. Further ahead, the NEOMIR infrared observatory, slated for launch in the mid-2030s, will allow detection of impact threats approaching from the direction of the Sun, such as the 2013 Chelyabinsk event.

From the discovery of Eros more than a century ago to today’s global detection networks, ESA said each new asteroid adds to scientific understanding of the Solar System’s past while strengthening humanity’s ability “to keep our planet safe.”