DART’s hit nudged a binary asteroid’s path around the Sun
Scientists show that while DART slowed Dimorphos by 33 minutes in its orbit around Didymos, the impact also slightly shifted the Didymos system in its solar orbit—about 11.7 micrometers per second along-track—thanks to ejecta momentum (beta ~ 2). Analyses using stellar occultations and radar data reveal Didymos has a density ~2.6 t/m^3 and Dimorphos ~1.51 t/m^3, suggesting Dimorphos is a rubble-pile; Hera’s 2026 measurements will provide confirmation.