Click for original image.

Cool image time! The picture to the right, cropped, reduced, and sharpened to post here, was taken on July 8, 2023 by the high resolution camera on Mars Reconnaissance Orbiter (MRO). It shows the northernmost interior rim of the caldera of Olympus Mons, the largest volcano in the solar system.

This one picture provides another way to illustrate the monumental scale of much of Mars’ topography. From the top to the bottom this steep scarp descends about 5,900 feet, in a little more than two miles. Compare that to the trails that descend the Grand Canyon’s south rim, which drop about the same distance but do it in distances ranging from three to five times longer.

In other words, this cliff wall is steep. Finding a route for a trail either up or down would be difficult at best.

The red dot on the overview map to the right marks this location. Note that the crater in this northern edge of Olympus Mons’ caldera has its own name, Athena Patera, with patera indicating that scientists believe it was created by volcanic processes, not an impact.

The picture also shows evidence of an ancient landslide, marked by the raised debris on the left side of the cliff’s base. The material suggests a very large section from the cliff’s bottom third separated and slide down as a unit. The soft nature of the ground here also suggests that this slide occurred a long time ago, and has since been eroded and covered by Martian dust.

The location, at 18 degrees north latitude, suggests there is little near surface ice here, a suggestion strengtened by the elevation, about 64,000 feet above the “sea level” of Mars. At that altitude — twelve miles high and more than twice the height of Mount Everest — the Martian atmosphere is very very thin, making the persistent presence of water, even as a vapor, very difficult.