This image was taken of the hills that resulted from uplifted rocks due to an impact that formed the 230-kilometer diameter Galle Crater.

These hills form a segment of a circle known as a “peak ring” and this particular formation makes Galle Crater look like a “smiley face” from orbit.

Small gullies, visible in the center of this image, have formed on the flanks of these hills and they have eroded back into the bedrock. The crater itself is probably billions of years old, yet these gullies are likely only hundreds of thousands of years old and may even be active today.

The small channels in these gullies are easily erased by the wind over long time periods, so we know these gullies must have been active recently.

Written by: Susan Conway  (4 March 2019)