NASA's asteroid-smashing DART mission revealed how battered space rock Dimorphos formed

This high-resolution view of the asteroid Dimorphos was created by combining the final 10 full-frame images obtained by the NASA DART probe's Didymos Reconnaissance and Asteroid Camera for Optical navigation (DRACO) and layering the higher-resolution images on top of the lower-resolution ones. Dimorphos is oriented so that its north pole is toward the top of the image.

On Sept. 26, 2022, NASA's Double Asteroid Redirection Test (DART) spacecraft slammed into the asteroid Dimorphos at nearly 15,000 mph (24,000 kph). 

DART's goal was to test our ability to defend Earth from a threatening rock by nudging it out of harm's way. The test was a brilliant success, and it also revealed how the battered asteroid came to be: Dimorphos didn't form on its own but rather as a ring of material flung off from its larger parent, Didymos.