The scientific community has surpassed a symbolic number: they have already been cataloged more than 40.000 near-Earth asteroids (NEA). This milestone not only measures technical capacity, but also consolidates a monitoring system that allows for anticipating risks and improving preparedness, with a prominent role for Europe and the ESA.
The detection rate has skyrocketed thanks to new facilities, analysis techniques and cooperative programs. It is a unprecedented acceleration which has transformed a craft into a global and continuous effort for planetary defense.
From Eros to the milestone of 40.000: a century that steps on the gas
The first NEA, The asteroid Eros (1898)It ushered in an era of slow progress: limited instruments, less precision, and uneven sky coverage. For decades, adding new rocks to the collection was a slow process.
The situation changed from the 1990s onwards, and especially during the 2000s, with programs dedicated to tracking. According to the ESA's Near-Earth Object Coordination (NEOCC), the focus shifted from close proximity to 1.000 NEA at the beginning of the century to 15.000 in 2016 and 30.000 in 2022...until now surpassing the 40.000 mark.
This trend is driven by a striking fact: 10.000 objects were discovered in just three yearsAnd the curve will continue to rise with the Vera C. Rubin telescope in Chile and the new ESA Flyeyedesigned to cover areas of the sky that currently remain as blind spots in surveillance.
The challenge now: to distinguish which ones pose a real risk
Detecting an object is the beginning: each NEA requires refining its orbit for years or decades. Although around 2.000 have a non-zero probability of impact In long-term forecasts, most are too small to constitute a significant danger.
Really big bodies —over one kilometerAsteroids with the potential for global effects are easier to spot and are practically cataloged. The operational focus is on asteroids in 100 to 300 metersthe range that could cause severe damage on a regional scale.
The models suggest that only around 30% none of those intermediate objects has been identified. Even so, none of the 40.000 listed rocks It represents an immediate threat to our planet, allowing us to focus our efforts on improving detection and monitoring.
From looking at the sky to taking action: tools to deflect asteroids
Planetary defense combines surveillance with response capability. ESA and NASA are advancing a common strategy: Hera travels to Dimorphos to study in detail the effects of the kinetic impact of DART, the first real asteroid deflection test.
The goal is to transform this technique into a reliable procedure in the face of a future threat. At the same time, complementary projects are being prepared, such as Ramses, oriented to encounter with Apophisand the space infrared telescope NEOMIR, designed to monitor the daytime side of the sky and close a large blind spot for tracking from Earth.
For Europe, this qualitative leap consolidates an infrastructure of surveillance and response increasingly robust. permanent surveillance The proximity of objects, international coordination, and the deployment of new missions place the region in a key position to protect the population and critical infrastructure.
The figure of 40.000 NEA marks a turning point: we've moved from discovering risk to managing it with better data, more coverage, and initial diversion tactics. Although There is no immediate threat. Among the cataloged objects, the effort to expand the census —especially among those from 100 to 300 meters— and to refine the orbits, along with missions such as Hera, NEOMIR and Ramses, outlines a more mature and effective planetary defense.
