Scientists have gained a deeper understanding of binary asteroids Didymos and Dimorphos, thanks to images collected by NASA's DART asteroid impact mission. Led by Olivier Barnouin from the Johns Hopkins University Applied Physics Laboratory, researchers analyzed the geological features and physical properties of the two near-Earth asteroids. The mission, named "Double Asteroid Redirection Test" (DART), focused on impacting the smaller body, Dimorphos, which orbits the larger rock, Didymos. The successful mission provided data that could aid in planning a planetary defense mission to deflect any potential asteroid threats to Earth.

Through a collaborative effort with the Light Italian Cubesat for Imaging of Asteroids (LICIACube) mission, scientists determined that Didymos displays rough terrain at high elevations, hosting large boulders and craters, while having a smoother surface with fewer rocks and craters at lower elevations. In contrast, Dimorphos, the moonlet companion, showed a variety of rock sizes across its mostly craterless surface and is marked with several cracks or "faults." The team concluded that Dimorphos likely formed from material ejected from Didymos, clumping together due to gravitational forces.

The research team assessed the number of craters on both asteroids to estimate their ages, revealing that Didymos is approximately 12.5 million years old, significantly older than Dimorphos, which is estimated to be around 0.3 million years old. Furthermore, a separate group of scientists, led by Maurizio Pajola from the INAF-Astronomical Observatory of Padova, suggested that the boulders on Dimorphos formed over different periods, indicating a direct inheritance from Didymos.

New findings also shed light on the surface properties of these asteroids. Naomi Murdoch and her team from the Université de Toulouse examined boulder tracks on Didymos, discovering that its surface consists of loose material with limited weight-bearing capacity. Additionally, Alice Lucchetti and her colleagues found evidence of boulders on Dimorphos experiencing fracture due to thermal fatigue over a relatively short timespan of around 100,000 years.

Colas Robin, from the Université de Toulouse, compared boulder sizes on Dimorphos to those on other asteroids like Itokawa, Ryugu, and Bennu, identifying similarities in rock morphology. This led the research team to propose a unified formation and evolution mechanism for these asteroids.

The collaborative research efforts have illuminated the intricate details of binary asteroids Didymos and Dimorphos, revealing valuable insights into their composition, formation, and evolution. These discoveries not only enhance our understanding of binary asteroid systems but also provide crucial information to support future planetary defense strategies.