planetary defense

DART MISSION'S NEW DISCOVERY

NASA's DART mission successfully proved the viability of the "kinetic impactor" technique for planetary defense by altering the orbit of the asteroid Dimorphos. Beyond its primary goal, post-impact analysis of DART's images revealed groundbreaking evidence of material exchange—"cosmic snowballs"—between Dimorphos and its parent asteroid, Didymos. This discovery confirms the YORP effect and shows that asteroids are dynamic "rubble piles," a critical finding that refines deflection models. The mission underscores the necessity of international collaboration, exemplified by ESA's follow-up Hera mission, to safeguard Earth from near-Earth object threats.