Archive | Site News RSS for this section

One (Earth) Year of Planet Four: Ridges

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

Dear Ridge Hunters,

Can you believe that it has been a year since we started to hunt for ridges??? We have accomplished a great deal in the space of a year! With 7,784 volunteers, we have made 135,976 classifications! We finished our first region (parts of Deuteronilus Mensae), second region (Protonilus Mensae) and third region (Nili Fossae)! We are now working on our fourth batch of images—from a new region in Meridiani Planum, closer to the currently operating Opportunity rover. Mapping our first three regions allowed us to understand the distribution of Nili-like ridges close to two of the Mars2020 rover candidate landing sites, and allowed us to see what sorts of geologic units were associated with the ridges. We found out that the ridge-bearing units are often buried units, and that polygonal ridges were almost never found in glacial terrain. There also wasn’t a strong correlation between craters and ridge networks. There was a strong correlation, however, between ridge units and ancient terrain from Mars’ oldest geological period, the Noachian. As its name suggests, the Noachian was a time when water was abundant on the surface of Mars. Our ridge discoveries suggest that the subsurface was also the site of extensive water-related processes. Since the subsurface would have also been protected from harmful UV rays, this watery environment could have been an interesting place to foster life.

Here is a map showing the ridges that were known before this project (green) and the enormous number of ridges in fine detail that we mapped throughout Nili Fossae (red):


But wait! There’s more! Intrepid ridge-hunter @bluemagi ventured outside of the Zooniverse-defined regions and is currently conducting a planet-wide search for more ridge-bearing regions. Here’s a map of the simply astonishing findings of @bluemagi across the rest of the planet (added in blue), which were transformed into an amazing .kmz file for Google Earth by @frognal! Check out their handiwork here and see if you agree with @bluemagi’s interpretations!


Thanks everyone, for a year full of amazing surprises in Planet Four: Ridges. Here’s to another year of exploring the planet Mars together!


5 Earth Years of Planet Four

Today we have a post by Dr. Candice (Candy) Hansen, principal investigator (PI) of Planet Four and Planet Four: Terrains. Dr. Hansen also serves as the Deputy Principal Investigator for HiRISE (the camera providing the images of spiders, fans, and blotches seen on the site). She is also a Co-Investigator on the Ultraviolet Imaging Spectrograph on the Cassini spacecraft that orbited around Saturn until the end of its mission last year. Additionally she is a  member of the science team for the Juno mission to Jupiter. Dr. Hansen is responsible for the development and operation of  JunoCam, an outreach camera that will involve the public in planning images of Jupiter.

Last week marked the 5th anniversary of Planet Four’s launch. Five years ago,  I was sitting in a meeting only partly paying attention.  I was focused on the brand new Planet Four website – it had just gone live and took off like a rocket.  I kept hitting refresh, enjoying each of the new introductions in the “Hello Everyone!” chat.

Now we have a community.  When I lurk (which I still love to do) I recognize the names – Pete J, wassock, Kitharode, angi60, p.titchin, ….  My heartfelt thanks go to Meg Schwamb for engaging with our citizen scientists on a regular basis!

Five years on you have measured fans and blotches in over 5 million HiRISE image cutouts.  We’ve applied statistical analysis and turned that into a catalog.  We can now query the catalog (where is the longest fan?  Which way is the wind blowing in Manhattan at the beginning of spring?)   We are very close to submitting our first paper describing the catalog with samples of potential results that can be pulled from it.  The second paper is already shaping up with comprehensive results for wind directions throughout spring – these results are the gold we were hoping for when we started this citizen science project.  The vision we had in the beginning is now coming true.

Right now we use models to understand Mars’ meteorology.  In order to test the models we need data – wind markers.  The atmospheric modeling scientists are very excited about seeing our results – results we wouldn’t have without your efforts!  Thank you as always for your generosity with your time!!


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


New Data Coming to Planet Four: Ridges Soon

Thanks to your help, we’ve finished search area two for Planet Four: Ridges. We’re working on analyzing the results and hopefully starting work on a paper based on those results. Laura has come up with a new region and slightly different type of polygonal ridge to search for. We’re working on getting that dataset processed and uploaded to the site. We hope to have this completed by the end of September with updated tutorials. We’ll keep you posted. In the meantime, Planet Four and Planet Four: Terrains could use some help if you can spare the time to classify an image or two.



New Images on Planet Four: Ridges

Thanks for everyone’s patience while we worked on getting new images on the Planet Four: Ridges website. The data is now live on the site. This set of images is the 2nd third of the new search region we’ve been focusing on. This search region includes  two of the three remaining potential landing sites for the NASA’s next Mars rover, called Mars 2020.  You can learn more about the region in this blog post. Dive in and search for polygonal ridges today on


An Update on All Things Mars

A quick update on all things Mars or at least all things Planet Four.

We got the referees’ reports back from the Planet Four: Terrains paper. The journal set it to two experts in the field. The read the paper and provided a critique of the paper. The reviewers gave positive feedback and have questions and concerns for us to address as well as other more minor requested changes to the manuscript. These additions and changes will improve the paper. So over the coming weeks, the science team will make modifications  additions to the paper draft over the coming weeks and we hope to have it back in to the journal as soon as possible. Then our written response to the referees’ report and the updated manuscript will go back to the referees for their second look. We’ll keep you posted as we make more progress.  In the meantime, there are new images we have uploaed on the Planet Four: Terrains website in need of review.

In regards to Planet Four: Ridges, thank to your help we’re completed 100 CTX images of our second search area. We’re currently working on getting new images onto the site. The CTX images are being processed as we speak and cut up into the subimages we need for the website. The images should hopefully be uploaded over the next week or so. Stay tuned to this space for more updates.

For Planet Four, we’re really at the stage of making the last changes and tweaks to the data analysis pipeline and switching gears to working on finishing the paper draft. We’ll have a separate blog post on that in the coming weeks.


New Images on Planet Four: Ridges

We’ve got some good news for your weekend. We’ve got brand new images on Planet Four: Ridges, expanding further south and east of our original area. More area covered, gives more opportunities to find unknown polygonal ridges. The more ridges we find, the better statistics we will have when we compare to other orbiter data sets to see if ground water is the main source for how these ridges form.  You can see where the search area is in comparison to our first data set below. The cyan show the footprints of the new CTX  images on the site, the magenta are the footprints of the CTX images  we had uploaded at launch. We thought the magenta area would take a year to search, so we’re thrilled that we can expand the search radius. Thanks for your time and your contributions. We really appreciated.


Generated using JMARS ( The magenta region shows the footprints of the CTX images previously searched The cyan area shows the new CTX data that has been uploaded to the Planet Four: Ridges site.


zoomed in view- Generated using JMARS ( The magenta region shows the footprints of the CTX images previously searched The cyan area shows the new CTX data that has been uploaded to the Planet Four: Ridges site.

We’ll have some more blog posts in the coming days and weeks to talk more about this new search region.

Dive in and search for polygonal ridges today at


Where Planet Four: Terrains Might Go Next

We’re now 60% through the third set of CTX images on Planet Four: Terrains. We’ve started to think about where we want to search next. We want to continue to fill in the area searched from -70 N latitude to the Martian South Pole. I’ve been coming up with the CTX image selection since the launch of Planet Four: Terrains. I wrote a code that goes through the list of publicly available CTX images and tries to pull  out a well balanced distribution of ice-free CTX observations across specific latitude and longitude bins. I thought I’d share my proposed set of new CTX images to search. I’ve sent this list of images to the rest of the science team, and I’m awaiting their feedback. The new set if accepted by the team, will fill in gaps in our coverage and especially between -70 and -75 N latitude. When we have a final list of CTX image to search after dataset 3, we’ll update you here on the blog.

Color Code for figures below.

Red= first dataset at launched and used in our first paper

Green= second dataset

Magenta = third dataset that expanded out to -70 – currently being reviewed on the site

Gray = 4th proposed set of CTX observations to search


The CTX image outlines are overlaid on an elevation interpolated map. Latitude and longitude lines are in 10 degree intervals for above and below.  The colors below represent geologic units, but for this comparison we’re focusing on spatial distribution and coverage. More details can be found here



More Planet Four – Introducing Planet Four: Ridges

Today we have a guest blog by JPL research scientist Laura Kerber.  Laura studies  physical volcanology, aeolian geomorphology, wind over complex surfaces, and the ancient Martian climate,

The surface area of Mars is almost the same as the area of all of the continents on Earth. Only a tiny fraction of these vast, untouched lands have been explored by rovers. Of the rest, much of it has still never been seen up close by human eyes. Today we’ve launched  Planet Four: Ridges, and we are asking for your help to explore a particularly interesting part of the Red Planet. The goal is to find polygonal ridge networks, which are intersecting lattices of thin ridges enclosing polygonal shapes.

A polygonal ridge network in the eastern Arabia Terra region of Mars. This image shows an area about 4 kilometers across

A polygonal ridge network in the eastern Arabia Terra region of Mars. This image shows an area about 4 kilometers across

Some of these ridges can be up to 50 meters tall, and from the surface would appear like the ramparts of an enormous fortress. Networks of ridges are usually formed via the filling of fracture networks either with lava, wind-blown sediment, or mineral deposits from circulating ground waters. These fractures are then transformed into ridges as the softer units around them get eroded by the wind. Your classifications on this site will help researchers find these networks and compare them to distributions of other features, such as mineral signatures, ancient valley networks, and dried up lakes. The images you see here are taken using the mid-resolution (6 meter per pixel) Context Camera (CTX) in orbit around Mars. Each participant views portion of images and decides whether or not there is a polygonal ridge network in the frame. We collect together everyone’s views on each image and this helps us find new ridge networks to study. The ridge networks can be subtle, but human eyes are well suited for pattern-finding, which is why we rely on you over computer algorithms.

More than 3.5 billion years ago, the climate of Mars was much different than it is today. The surface of Mars shows evidence for hundreds of lakes, and thousands of kilometers of flowing rivers. During this time and earlier, warm groundwater may have circulated in the Martian subsurface, potentially providing a protected home for early Martian life. One piece of evidence for groundwater during this period is the presence of clays that are deep in the crust (often visible in the central peaks of impact craters). Another is the presence of mineral veins, which are formed when warm water carrying elements in solution deposits minerals on the walls of fractures. Hot water or steam can also alter wall rocks of fractures, causing the walls to harden compared with the surrounding material. Later, after the crack cools, the minerals become harder than the rock types that surround them, so that as the surrounding unit get eroded by the wind, what was originally a fracture becomes a ridge.


A ridge network filled with the mineral gypsum located in the Lut Desert of Iran, one of the world’s hottest and most lifeless deserts

A close-up of a Lut Desert gypsum ridge

A close-up of a Lut Desert gypsum ridge

Not all polygonal ridge networks are formed due to circulating groundwater, however. Sometimes open cracks on the surface get filled with windblown dust and sand, and that part gets preserved. Lava can also fill up cracks, either as it rises through the subsurface as magma, or if it is flowing along and drips into a fracture network. Finding all of the ridge networks on Mars helps us untangle which networks were formed by which process, all the while learning more about the intriguing wetter period in Mars’ history. This project focuses on the Eastern Arabia Terra region of Mars, where several ridge networks suggestive of mineral veins have been found.

A crack that has been hardened by hot steam escaping. It has since been brought into relief by the erosion of the surrounding rock. Campo de Piedra Pomez, Argentina.

A crack that has been hardened by hot steam escaping. It has since been brought into relief by the erosion of the surrounding rock. Campo de Piedra Pomez, Argentina.

As the project continues, we hope to share more background information on these interesting features here on this blog. Meanwhile, why not go find some ridge networks? Visit to start looking.