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The Cerberus Fossae

The focus of this post will be on the area of the Martian surface that Planet Four: Craters volunteers have been marking craters on, the Cerberus Fossae.

The Cerberus Fossae is a set of west-north-west trending and almost parallel fissures or fractures that cut across the Cerberus plains on Mars. Evidence suggests that the fissures have been formed by faults that pulled the crust apart in the Cerberus region (9°N, 197°W).

Ripples seen at the bottom of the fault are sand blown by the wind. The underlying cause for the faulting was believed to be magma pressure related to the formation of the Elysium volcanic field, located to the northwest. The faults pass through pre-existing features such as hills, indicating that they are a young feature by the standards of those found on the surface.

In fact, this area of Mars has been identified as having the youngest volcanic plains on Mars. Early crater-counting efforts have suggested that the youngest lava surfaces in the area are less than 10 million years old. This is why it is of such interest to future missions to Mars, as a location where seismic activity might still be happening. To help predict the amount of seismic activity to expect, we need your crater markings to make a more accurate estimate of the age of the region.

If you have any other questions regarding some of the things you have spotted on Planet Four: Craters, please feel free to ask on Talk, and in the mean time please keep marking on!


Crater Features

Since the launch of Planet Four: Craters a few weeks back, we have had several Talk posts regarding different features and markings that have been spotted in and around the craters themselves. This post will go through what some of these markings might be, and hopefully answer some of the questions you have had!

Recurring Slope Lineae (RSL)


Recurring slope lineae are narrow, dark markings found on steep slopes (like crater edges) that incrementally lengthen during warmer periods, then fade over cooler seasons and can recur over multiple Martian years. They can grow to be several hundred metres in length, and it has been suggested that they are caused by wet flow – originating from melted ice.

Active Gullies


Martian gullies are small networks of narrow channels, along with their associated down slope deposits, that occur on steep slopes, especially on crater walls. It has been suggested that they are formed by a flow of dry material, supported by a layer of dry ice just below the surface.

New Impacts

new impact

As the name suggests, these are craters that have been formed by impacts that have occurred in the near past. They are found all over the surface of Mars, and although they vary in size the smaller ones are much more frequent. They can be spotted by the darker coloured ejecta formed around them (due to the disturbed surface material that has yet to settle), or in some cases the presence of brighter patches – indicating where subterranean ice has been revealed.

If you have any other questions regarding some of the things you have spotted on Planet Four: Craters, please feel free to ask on Talk, and in the mean time please keep marking on!


Calling All Undergrads: Spend A Summer Working on Planet Four in Taiwan


I’m a postdoctoral fellow at the Institute of Astronomy & Astrophysics at Academia Sinica (ASIAA)  in a Taipei, Taiwan. As part of the 2015 ASIAA Summer Student Program, we’re looking for an undergraduate student to come to Taipei for the summer, from July 1st-August 28th, to work on Planet Four related research.

Last year, Chuhong Mai participated in the program and helped get the map project information we need to make the final catalogs for the first Planet Four paper. As a result of her efforts last summer, Chuhong is going to be co-author on the paper. You can learn more about her experience at ASIAA and as part of the summer program here.

ASIAA operates in English, and all research will be conducted in English.  The description of this year’s project can be found here. The aim will be help develop tools to look at wind directions based on the Planet Four fan markings for one of the HiRISE targeted regions  (likely Inca City or Manhattan) and see how fan directions change from year to year. Details about the Summer Student Program including rules and restrictions can be found here.

Applications are due before March 20th. If you have questions or if you would  like to know more, you can contact me via email at  mschwamb AT

Using Tag Groups to Collect Images on Talk

More on making tagged group collections from the Darren on the Zooniverse blog


Hashtags are an important element of how the current generation of Zooniverse’s Talk discussion system* helps to power citizen science. By adding hashtags to the short comments left directly on classification objects, users can help each other (and the science teams) find certain types of objects—for instance, a #leopard on Snapshot Serengeti, #frost on Planet Four, or a #curved-band on Cyclone Center. (As on Twitter, hashtags on Talk are generated using the # symbol.)

One of the ways in which zooites can take advantage of hashtags is by using Talk’s tag group feature. A tag group (also called a “keyword collection”) is a collection that automatically populates with all of the objects that have been given a specific hashtag by a volunteer.

For instance, here is a Galaxy Zoo tag group that populates with all Galaxy Zoo objects that have been tagged #starforming. It will continue to automatically add new…

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The Sun is back!

 I wrote a post on my new blog showing how I go about finding out what’s currently going on at the southpole of Mars!
Sorry for the cross-linking, but there’s no way to show the nice IPython notebooks (combing text and code) in a clear and pretty format here in WordPress:

Animated markings

After the first day of our currently ongoing workshop for Citizen Science I have reached my personal goal for the day and created a tool to display an animated version for all the marked blotches of a PlanetFour image.

Here’s the result:

More to come in the upcoming days.

Dry ice snowfall

About a week ago our colleague and a resident polar scientist on the Mars Climate Sounder (MCS) science team Dr. Paul Hayne wrote this Planetary society blog post. He talks about CO2 snowing on Mars! If you are interested to know why we think that it snows dry ice on Mars or what shape CO2 snowflakes are, go check it out! And let us know your thoughts on how it affects the areas that you are helping us to analyze!


New Link for the Live Chat

Some technical difficulties but we are live


Standing on the Surface

With the HiRISE images we show on Planet Four, you’re peering down at the Martian surface from above, seeing the fans and blotches that we want you to you mark.  What would something like the image below  look like from the ground if you were standing on the thawing carbon dioxide ice sheet during the Southern spring?


Well, if the geysers were actively lofting carbon dioxide gas and dust and dirt from below the ice cap up onto the surface and into the Martian air, you’d probably see something like the artist’s conception below.

Image credit; Arizona State University/Ron Miller

Artist’s rendition of geysers on the South Pole of Mars – Image credit; Arizona State University/Ron Miller

How high are the plumes? Current estimates suggest that the geysers and material it lofts stay relatively close to the ground going probably no higher than about 50-100m into the air according to previous estimates based on fan length and simple deposition models. Though more likely, the geysers achieve smaller heights than that most of the time. To try and directly measure the geyser plume heights, stereo imaging where Mars Reconnaissance Orbiter pointed at the same spot twice at different look angles has been used. The two resulting HiRISE images are then combined to give height information in much the same way our brains combine the  images obtained from our eyes, each viewing at a slightly different angle and position than the other, to get depth perception. HiRISE would have been able to see the geyser plumes above the ground in the combined stereo pairs,  if the majority achieved heights of 50-100 m, but no image to date yet has caught a detection of a plume. So that suggests that the geysers may not reach these maximum heights but instead only go up to maybe 5-10m off the ground.

Your clicks may be able to help constrain better the height of the geyser plumes. With your classifications, we will have the largest sample of fan lengths and directions and blotch radii ever measured on the Martian South Pole. With the fan lengths from your markings,  a measure of the terrain’s slope, and an assumption for the particle size of the Martian dirt/dust being entrained by the escaping carbon dioxide gas, you can estimate the maximum height needed to loft the material for it to fall at a given distance from the geyser for a range of wind speeds.

to the North!

Hi there!

The PlanetFour so far has images only from Martian southern hemisphere. But northern polar areas also show a lot of activity and partially similar features! Have a look at this fresh video released by the JPL today. It shows fans, ice cracks and blotches similar to those that we are marking here, on Planet Four.

We are planning to add northern hemisphere images to this project too. Stay tuned!