Archive | December 2017

More on Merdiani-type Polygonal Ridges

Today we have a guest blog by JPL research scientist Laura Kerber, one of  our lead researchers on Planet Four: Ridges .  Laura studies  physical volcanology, aeolian geomorphology, wind over complex surfaces, and the ancient Martian climate.

Merdiani-type Polygonal Ridges


Merdiani-type Polygonal Ridges

Hello Ridge Hunters!

We are nearing the end of the year on Earth, but we’re only in Martian month 4 on Mars (Solar Longitude = 99.2; Sol number = 214). But what a year on Earth it has been for Planet Four: Ridges. Since our launch on January 17th, thanks to 7,453 registered volunteers, we have retired 11,999 images! We have mapped ridges the length and breadth of the dichotomy boundary near Protonilus Mensae, Nilosyrtis Mensae, and Nili Fossae.

We are now moving into the strange and wondrous land of Sinus Meridiani, not too far from where the Opportunity Rover has been roving along at what might be the shore of a vast, ancient inland sea. The ridges in this new area are different—they are flat on top and splintered, and they can be dark or light compared to the background terrain. Instead of true polygons, they make broken circles. Take a look at the update tutorial to see examples of this new and strange type of ridge. By mapping ridges in Sinus Meridiani, we can compare and contrast them with their more northerly brothers, and determine why their morphologies are so different and what this meant for their environment and process of formation.

Happy Ridge Hunting, and if you find anything strange, let us know in the comments!


Planet Four: Ridges is Back

We’re thrilled to announce that Planet Four: Ridges is back. We’ve completed the Arabia Terra search for now, and today we’ve launched a new workflow to search for a different type of polygonal ridge that we’ve searched for previously. This new type of polygonal ridge is found in Sinus Meridiani,  a darker area of Mars located in the northern midlatitudes of  just south of the equator. You can see it’s located below Arabia Terra, the previous region we’ve been searching.


Hubble Space Telescope Image of Mars. Arabia Terra is the large triangular shaped region in the center. Sinus Meridiani can be seen as the darker region below Arabia Terra. Image Credit: NASA, ESA, and L. Frattare (STScI)

Meridiani-type polygonal ridges often look like broken spider webs or tattered lace. These ridges do not usually form neat boxy shapes, but they can be interconnected, looping, or branching. We need your help to identify these features, so that we can see if the Meridiani-type polygonal ridges follow the same trends we’re in seeing in the Arabia Terra polygonal ridges.

Meridiani-type Ridges in CTX subframes

We are continuing to work on analyzing and reducing the classifications from the Arabia Terra search. You can learn more about that in this previous blog post from Laura.

Dive back into Planet Four: Ridges today at