By Samuel Lopez | USA Herald – For decades, planetary defense planning focused on a familiar threat: asteroids and comets born within our own solar system, following predictable paths shaped by the Sun’s gravity. That framework is now being tested by a new class of objects—interstellar visitors like 3I/ATLAS—that arrive from beyond our stellar neighborhood, move faster than most known bodies, and may behave in ways that challenge existing assumptions.
3I/ATLAS, currently passing through the inner solar system, is not dangerous to Earth. Its closest approach on December 19 will occur at a safe distance of roughly 270 million kilometers. But safety today is not the point. The object’s unexpected physical behavior, combined with its interstellar origin, is forcing scientists and defense planners to confront a broader question: are Earth’s planetary defense systems prepared for objects that do not play by familiar rules?
Planetary defense is often misunderstood as a single technology or weapon system. In reality, it is a layered process that begins with detection, continues through tracking and characterization, and only then moves—if necessary—into mitigation strategies such as deflection. Each step depends on time. The earlier an object is detected and understood, the more options humanity has.
