New Images on Planet Four: Terrains

We’ve uploaded new images to Planet Four: Terrains this week. This dataset continues to fill in areal coverage to look for spiders outside of the south polar layered deposits and also examining the overall distribution of spiders and other features.

You’ll notice some changes to the look of the classification interface. Over the past several months, the Zooniverse development team has made updates and changes to the classification pages.  This  Zooniverse Talk thread is where you can share your thoughts and feedback on the new look.

Dive in today a


(Southern) Spring is Coming!

Southern Spring is coming to Mars very soon. May 22nd marks the official start of Spring at the Martian South Pole. We’ve been busy reducing the most recent sets of classifications from Planet Four: Terrains looking for new spider locales to target when the HiRISE and CaSSIS seasonal campaign starts. The CaSSIS camera is a recent addition to Mars, aboard the European ExoMars Trace Gas Orbiter (TGO). It takes slightly higher resolution images than the CTX, whose images we show on the Planet Four: Terrains website. CaSSIS is designed for  stereo imaging which is key for measuring depths and heights of features. Also unlike CTX, CaSSIS is equipped with several filters so color images can be made. Even with the addition of CaSSIS,  the decade old HiRISE remains the highest resolution imager  (~30 cm/pixel) in action around the Red Planet.

The PI of Planet Four: Terrains, Candy Hansen is a member of the HiRISE and CaSSIS science teams , and can ask for images to be potentially taken of the Solar Polar region if we find something interesting worthy of followup observations. We’ve asked for a few additional candidate spider locations (plotted below between -70 and -75 degrees latitude) outside of the South Polar Layered Deposits to be imaged if the observations can be squeezed into these cameras’ packed schedules. If confirmed in the higher resolution images, these will be the furthest spider identifications from the South Pole. Fingers crossed we’ll get some more detailed images of these places over the coming months.



Green boxes denote candidate spider/araneiform locations found by Planet Four: Terrains

Thanks for all your help. We plan to have new images on the Planet Four: Terrains site by the start of Southern Spring, so stay tuned!




First publication submitted!

We have finally submitted our first paper for the original Planet Four project to the Icarus journal where it is now officially “Under Review”!

(Above figure is one of the paper where we demonstrate one of the reduction steps to identify noise and create averaged clustered markings. I think it demonstrates well the power of our chosen methodology.)

Thank you to everyone to stay with us for so long without seeing any published results, but I think when you will see the work and care that we put into it, you will understand why it took us so long. One of the reasons was, as we possible mentioned before on this blog, that our Zooniverse project is actually one of the most difficult ones, where we ask all of you to precisely mark objects in the data presented to you. This required a spatial clustering pipeline with a long evaluation and fine-tuning phase.

Which brings me to the point of “see[ing] the work”: we have now managed to have the submitted preprint published on the well known preprint server and you can get your hands on a copy right now! Just click on this link and you will be sent to the arXiv page for our preprint:

Enjoy the (long!) read and don’t shy away to put any questions you have in the comments section below!

South Polar Locales Comprising the First Planet Four Catalog

The science team is working on ticking off the last things on the todo list before we can submit the first Planet Four paper.  Michael is in the last stages of making edits and changes to the paper draft.  We’re nearly over the finish line. While Michael has been working hard on the manuscript text and catalog files, we’ve  also been iterating on some changes to the figure Anya made that shows all the locations making up the Seasons 2 and 3 monitoring campaign that are part of our fan and blotch catalogs based on your classifications. I thought I would share some of the versions Anya made:


All the locations monitored by HiRISE that were classified by Planet Four volunteers to make the Season 2 and 3 catalog. Credit: G. Portyankina


All the locations monitored by HiRISE that were classified by Planet Four volunteers to make the Season 2 and 3 catalog. A labeled version (for clarity a few regions don’t have their names listed). We note all of these names are unofficial nicknames and are not IAU approved. Credit: G. Portyankina

It’s really exciting to think back to when this project started in 2013 and now see this plot, where I can say we have fan and blotch identifications for HiRISE images taken in Season 2 and 3 Southern Spring/Summer for all of these plotted points.

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

Planet Four at the Division for Planetary Sciences Meeting

The American Astronomical Society’s Division for Planetary Sciences meeting was held last week in Provo, Utah. We presented results from Planet Four: Terrains, but it wasn’t the only Planet Four project represented. There was an update on Planet Four. Chase Hatcher attended the meeting ready to talk about Planet Four. Chase is, a student at the University of North Carolina at Chapel Hill and he spent this past summer working in Colorado with Anya and Michael on Planet Four analysis.

Chase presented a poster on his work at DPS as well as some of the other progress on the Planet Four data analysis we’ve made. Thanks Chase for all the hard work and for representing Planet Four. You can find Chase’s poster below.



Planet Four: Terrains at the Division for Planetary Sciences Conferences


Image credit: DPS/AAS/

Greetings from Provo, Utah. I’m here to present science results on Planet Four: Terrains among other things.  The DPS is now trying out a new set of poster presentations using large touch screens, which they are calling iPosters. My abstract was selected for an iPoster. This means you can currently explore view and my iPoster online here. Enjoy!