Take a look at this ‘open-eyed’ crater on Mars
This image of Aonia Terra, an upland region in the southern highlands of Mars, shows a 30-kilometre-wide (19-mile-wide) landscape of winding channels. Resembling the veins that run through a human eyeball, these channels likely carried liquid water across the Red Planet’s surface some 3.5-4 billion years ago. The image was taken by the European Space Agency’s (ESA) Mars Express on April 25.
These channels appear to be partially filled with some kind of dark material and actually appear to be raised above the surrounding land in places. The ESA proposes many possible explanations for this. It is possible that erosion resistant sediments were deposited at the bottom of the channels when the water flowed through them. It could even be that the channels filled with lava later in Mars’ history.
ESA’s Mars Express image reveals many different colors on the surface around the crater. This suggests that this region of Mars is made up of a variety of materials. The surface is a warm red, fading to a darker brownish gray closer to the crater to the south (which is on the left side of the image above). In that region, many hills can be seen. These flat-topped towers of rock are created when water, wind, or ice gradually wear away the land.
A field of dark dunes rests on a lighter surface within the crater. Closer inspection revealed that the crater is apparently filled with more cone-shaped ridges and hills. These can be seen as evidence of many materials accumulating within the crater in the past.
The surface is lighter and smoother to the north of the crater (which is on the right side of the image). The rims and channels of the main crater appear less well defined on this side. At the far right of the image, the surface becomes even smoother.