NASA's DART Mission Unveils Asteroid Material Exchange in Binary System
Analysis of NASA's DART mission images reveals that asteroids Didymos and Dimorphos exchange material, providing direct evidence of the YORP effect and indicating that near-Earth asteroids are more dynamic than previously thought.
Recent analysis of images from NASA's Double Asteroid Redirection Test (DART) mission has revealed that the binary asteroid system comprising Didymos and its moonlet Dimorphos is more active than previously understood. The study, led by the University of Maryland, identified faint, fan-shaped streaks on Dimorphos' surface, indicating material transfer between the two bodies.
These markings provide the first direct visual evidence of the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, a phenomenon where sunlight accelerates the rotation of small asteroids, causing them to shed debris. In this case, material from Didymos appears to have been ejected and subsequently landed on Dimorphos.
Jessica Sunshine, the study's lead author and a professor at the University of Maryland, noted initial skepticism about the findings. "At first, we thought something was wrong with the camera, and then we thought it could've been something wrong with our image processing," she said. "But after we cleaned things up, we realized the patterns we were seeing were very consistent with low velocity impacts, like throwing 'cosmic snowballs.' We had the first direct proof for recent material transport in a binary asteroid system."
The discovery suggests that near-Earth asteroids are more dynamic and subject to constant reshaping than previously believed. This insight could enhance our understanding of asteroid evolution and inform planetary defense strategies.
The findings were published on March 6, 2026, in The Planetary Science Journal.