Figure 1 : Asteroid Ida.

From: Cracking up on asteroids

Figure 1

This enhanced composite image of Ida, a silicate asteroid more than 50 kilometres in length within the main asteroid belt, was taken by the camera aboard the Galileo spacecraft on 28 August 1993. Colour differences in the image reflect both the steep topography and the varied physical state and composition of the regolith on Ida. Delbo et al.1 show that temperature cycling is the main source of regolith formation on kilometre-sized and smaller asteroids. Image: NASA/JPL