Archive by Author | Meg

Planet Four in French

The Planet Four website is now available in French. A big thank you to Louis who volunteered to lead the translation effort. We asked him to write a few words:

My name is Louis Verhaeghe, I am a French student, I am currently in BTS CRSA (Brevet de Technicien Supérieur – Design and Realization of Automated System), I intend to continue my studies via a License in Robotics Engineering.

Later I would like to work on planetary satellites and maybe if I’m lucky on intergalactic probes.
Although I have more than 12,000 classifications on Zooniverse, I think the translations of different projects is my most important contribution because it allows thousands and thousands of French speakers who do not speak English to be able to participate in the immense citizen science effort that is the Zooniverse platform.
I am also a fairly seasoned amateur astronomer, I like to believe that the Fermi Paradox will find an answer one day.

If you’re interested in translating one of the Planet Four projects do get in touch on Talk!

À vos marques, prêts, partez!

The South Polar Layered Deposits

If you might have seen images like the ones above on Planet Four: Terrains and wondered what’s going on with these banded features in these images. That’s the South Polar Layered Deposits (SPLD). The SPLD are alternating layers of ice and dust, giving it that banded look. The are thousands of layers contained in this ~3km geologic unit. The SPLD has a counterpart in the North, unshockingly known as the Northern Polar Layered Deposits (NPLD). The SPLD (like it’s northern sibling) are mostly composed of frozen water ice in between the dust layers.

It is thought that the alternating layers are telling us that these formed from a cyclic climate process. Mar’s obliquity (axial tilt) has changed dramatically over time. The Moon prevents the tilt of Earth from changing significantly from 23.5 degrees, but Mars does not have a large moon. Instead for Mars, the axial tilt can change up to about 60 degrees. Like on Earth, the reason for seasons on Mars is the axial tilt. The more extreme the axial tilt, the more extreme the season are. Climate scientists think that the SPLD formation is related to the changing axial tilt of Mars.

Researchers are still learning about the properties of the SPLD and what it tells us about Mars’ climate history. In 2011, the ground penetrating radar measurements from Shallow Radar (SHARAD) instrument on Mars Reconnaissance Orbiter (MRO), the same orbiter that provides the images we show on the Planet Four projects, uncovered a large carbon dioxide ice reservoirs hidden, lurking below the surface of the SPLD

Extent of the SPLD and thickness of the SPLD (Image credit: NASA/JPL/ASI/ESA/Univ. of Rome/MOLA Science Team/USGS)

Here’s a high resolution view of the SPLD from the HiRISE camera:

Pocket Mars Reconnaissance Orbiter

The images we show on the Planet Four projects come from Mars Reconnaissance Orbiter. Although MRO won’t be coming back to Earth, you can have your very own pocket-sized MRO.

If you’ve got a 3-D printer, you can try your hand at printing out your own mini-MRO to keep you company while classifying images on Planet Four, Planet Four: Terrains, or Plant Four: Ridges.

Where Do the Images Shown on the Planet Four Projects Come From?

The images you review on the Planet Four projects (Planet Four, Planet Four: Terrains, and Planet Four: Ridges) come from two different cameras onboard NASA’s Mars Reconnaissance Orbiter (MRO). MRO has been in orbit around Mars since March 2006. Science operations commenced in November 2006. Nearly 14 years later and MRO has continued to observe and monitor the Red Planet.

Artist Impression of Mars Reconnaissance Orbiter in orbit (Image credit: NASA JPL)


MRO is equipped with several instruments :

  • HiRISE (High Resolution Imaging Science Experiment) – a high-resolution color imager
  • CTX (Context Camera) – grayscale mid-resolution imager
  • MARCI (Mars Color Imager) – color weather imager used to monitor clouds and Martian dust storms
  • CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) – spectrometer that can take composition images of the surface – 2-dimensional maps of the different compositions of the surface
  • MCS (Mars Climate Sounder) – probing the conditions within the Martian atmosphere: temperature, dust, and water vapor concentrations
  • SHARAD (Shallow Radar) – ground-penetrating radar to explore the structure of the Martian subsurface

As MRO orbits Mars, it performs a complex ballet where the different images are taking observations at different times throughout the orbit. The observations are requested by the instrument science teams who are doing a wide variety of science with MRO.

On Planet Four, we use the high resolution color images from HiRISE which can see from orbit surface features down to about the size of your average. HiRISE has a resolution of about 30 cm/pixel. HiRISE is the highest resolution imager sent to another planet in Solar System. In Planet Four: Terrains and Planet Four: Ridges we’re using the grayscale CTX images which covers a wide area but at a lower resolution (6-8 m/pixel) compared to HiRISE. CTX actually provides context for where HiRISE and CRISM are observing and every time these two instrument takes an observaiton, CTX snaps an image as well. HIRISE is so high-resolution that CTX provides the context to tell researchers about what the topography and area around the HiRISE image. If you’ve ever checked out Google Mars visible imagery, you’ve seen some of CTX’s handywork. CTX has image nearly all of the Martian surface several times over.

MRO has now completed over 60,000 orbits around Mars and sent back a whopping 388 terabits of data to Earth. It’s still going strong and HiRISE and CTX are continuing to function. As long as they do, we hope to be able to put those images onto the project sites to continue exploring the current and past climate of Mars.To mark 15 year since the launch of MRO, NASA has put together a great collection of images taken by the spacecraft and its imagers and this video below to mark a decade of MRO science shows some of the striking images the cameras onboard have taken of the Red Planet.

A View From Mars

Anya and Michael were recently interviewed about Planet Four for the Fiske Planetarium’s podcast, A View from Earth. Have a listen down below.

Planet Four Roulette

With three projects under the Planet Four Organization, it might not be an easy task to decide which project to dive into today. You’re in luck. We’ve got you covered. Fancy a spin of the wheel?

You have a catalog of seasonal fans and blotches… Now what?

Today, I wanted to share a bit of the analysis we’re working on for Planet Four. Taking the Planet Four fan and blotch catalog from Season 1 and 2 of the HiRISE monitoring campaign, we’re now looking at what the average/dominant wind directions, derived for your classifications is telling us about the Martian south polar surface winds.

I wanted to show an example of what the science team is doing this. Tim Michaels has joined the science team and he’s an expert on climate modeling. We’re using the MRAMS (Mars Regional Atmospheric Modeling System) climate model/computer simulation to compare the fan directions to what direction is expected from the simulation. MRAMS is taking all the physics that we have about atmospheres and how we think these processes are working and computes what the atmosphere is doing and its conditions. We’re working on comparing the output of MRAMS to the wind directions we infer from the Planet Four fan directions.

Below is an example of one of the types of plots the team has been looking at. Here we show where the dominant fan direction is pointing in the full HiRISE frame from the Planet Four fan catalog. Think of this has telling you where the wind is headed. Each arrow represents a HiRISE observation image taken as part of the Spring/Summer monitoring season. The color of the arrows tell you which block of the Spring/Summer season the image was taken. For timekeeping on Mars, we use L_s, solar longitude, where Mars is located in in orbit around the Sun. L_s=180 is early Southern Spring. 220 is into early Southern Summer. We have 2 Mars Years as part of the current Planet Four catalog We plot the directions from each separately in the left and middle plot, and jointly all together in the right most plot. The left and middle plot show the topography that was used by the MRAMS model and the right most post shows the highest resolution topography measured by the Mars Global Surveyor’s Mars Orbiter Laser Altimeter.

Plots like this help the team look at the impact of topography and the structure of the local surface that might be contributing to how the wind blows. From this image we see that Giza is on the edge of an area where the elevation is dropping as we move more northward in latitude. Here we can see that the topography is likely playing a significant roll with the wind likely traveling from the highest elevations region (bottom of the plot) to the lower elevations. We’ll be able to compare with the detailed ouptut from the MRAMS simulation, but the topographic plots help us put the results from MRAMS in context. The simulation will tells us what direction it think the wind is blowing, but it won’t tell us necesarily why. These topographic plots help us add more explanation to the story.

Image Credit: Tim Michaels

The Invisible Winds that Shape the Fans

Today we have a guest post by Tim Michaels. Tim is a research scientist at the SETI Institute who studies how the weather and climate of other worlds affects their surface features.

The Planet Four science team has recently been using the catalog of your fan markings to compare to the wind speed and direction estimated by computer calculations of how Mars’ atmosphere moves around.  These wind estimates are calculated by a complex computer program known as a mesoscale atmospheric model, very similar to those that forecast the daily weather on Earth.  There are no actual wind measurements in the southern polar regions of Mars, so we use these modeled wind estimates to better interpret what your fan markings tell us about the planet’s weather and climate.

The figure below shows an example of the modeled wind estimates near the Manhattan Classic fan site (86.4S, 99.0E) in the early evening at Ls 190.  The area shown is about 135 km by 135 km, south is toward the upper right side, and every arrow is about 1.5 km apart (every model gridpoint; the numbers on the sides count these).  This area is at the head (top) of the great south polar valley Chasma Australe, and the white topographic contours (in meters) show the upper reaches of that valley running downhill from center right toward the lower left.  The arrows show wind direction and speed (arrow length, see the 10 m/s scale in the upper right corner).  Wind speed is also indicated by the color of the arrows — cooler colors (like blue and purple) for the slower winds, warmer colors (like red and orange) for the faster winds.  The fastest wind speeds in this scene are about 11 m/s.


You can see how the wind directions and speeds vary a lot across this area — those patterns change quite a bit with the time of day, as well.  Our preliminary results show that the strong winds from the east near the center of this figure may be related to the formation of the fans in this area.  Much more work still needs to be done to better understand what all of your markings of fans and blotches tell us about the winds on Mars, but we wanted to give you a glimpse of what the (invisible) winds that sculpt the fans may look like.

An Update on Planet Four: Ridges

It’s been a busy summer for the Planet Four: Ridges science team. The project’s first research paper was submitted to the journal Icarus. A big thank you to all the volunteers and our active volunteers on Talk who have contributed lots of great polygonal ridge locations that went into the paper’s analysis. Below you’ll find a map showing the CTX images that were searched by Planet Four: Ridges volunteers using the main classification interface as part of the study.

Map of the locations of the CTX images searched on the Planet Four: Ridges website that was used in the analysis of the project’s first paper.

The first step in this process is getting the referee reports back. The referees are researchers studying Mars who give independent feedback on the paper. Normally the identities of the referees are anonymous, and the author does not know who they are. The referees read the paper and give the editor their opinion on whether the paper is of sufficient quality to be published in the journal and give feedback on how the manuscript/work could be improved. The job of the referee is to point out areas that should be clarified in the paper and where more analysis needs to be done if needed before the paper can be accepted for publication in the journal.

We’ve recently received the feedback from the two anonymous referees. The referees see that there is merit in the Planet Four: Ridges catalog. Thye also gave a lot of great feedback on where we can improve the analysis and manuscript. We’re working on addressing the referee’s comments and taking on board their feedback. We’ll keep you posted as we move through the paper revision process. We’ll do some further analysis, reworking of the paper draft, and add some additional text. Once we’ve done that, we’ll write a response to the referee’s report outlining what was changed/added to the paper to address the points raised by the referees. Then we’ll resubmit the paper and send the response to the referees to the journal. The referees will read everything and send back further questions, concerns, and points that need clarification. We will post more details about the key results of the paper once the paper is accepted and published by the journal.

A Peek at the Planet Four Catalog

The Planet Four science team is collaborating with machine learning researchers in Australia. We’re working on a joint paper that looks at using the current Planet Four seasonal fan and blotch catalog that was generated from the HiRISE season 2 and season 3 images from the original Planet Four website. Michael Aye made some great images for the paper showing examples of what gets generated from your classifications. I thought I would share some of the figures.

In the figures below you’ll see the Planet Four subject image or tile on the left that we have asked volunteers to classify and the right the image is overlaid with the resulting fans (shown in green) and blotches (show in magenta) identified. Each Planet Four subject image has about 30 people review it and map fans and blotches they see in image. We then take all the individual marks and combine them together to identify which sources are fans or blotches. This blog post gives some more information on how we developed the clustering code that combines your classifications together.

With Planet Four 2.0, the current version of the project, we’ll be using the same method and software to combine the markings you are making now to identify the fan and blotches in the subject images. So think of the images below as a sneak peek of what your clicks will be turned into.