NASA images unlock complex history of two near-Earth asteroids

In the moments before NASA’s DART spacecraft slammed into the asteroid Dimorphos in a landmark planetary defense test in 2022, it took high-resolution images of this small celestial object and its larger companion Didymos.

These images have enabled scientists to unravel the complicated history of these two rocky bodies located in the vicinity of Earth and gain insight into the formation of what are called binary asteroid systems – a primary asteroid with a secondary moonlet orbiting it.

An analysis of the craters and surface strength on Didymos indicated it formed about 12.5 million years ago. A similar analysis indicated Dimorphos formed about 300,000 years ago. Didymos probably formed in our solar system’s main asteroid belt, between the planets Mars and Jupiter, and then was knocked into the inner solar system, the researchers said.

An examination of the largest boulders on Didymos and Dimorphos gave clues about the origins of the two asteroids.