Adding Some Red (Planet) to the Holiday Season

Image Credit: NASA/JPL/University of Arizona   ( )

Image Credit: NASA/JPL/University of Arizona ( )

Adding more red (planet) to this holiday season, another new HiRISE image of Inca City was publicly released by the HiRISE team this month. This is the 6th image from the sequence taken this fall as part of Season 5 of the seasonal monitoring campaign (We’re currently showing images from Season 4 on Planet Four).  The image sequence was released as part of the public vote we organized with the help from our friends on the HiRISE team. You can find the rest of the sequence here.

Close to the Sun

Mars is slowly coming towards summer in the southern hemisphere and the same time to the perihelion on its orbit around the Sun.

This project is focused on fans in Martian southern polar areas. But do you know why southern? There are similar features in the northern polar areas, but they are much smaller. In fact, for quite some time scientists believed that the kind of activity that produces dark fans and blotches (cold CO2 jets) did not happen in the north. They thought so, because they could not see any signs of it in the north. Or better to say, they could not resolve it. At that time, from 1996 to 2005, the images of martian ground were coming from the Mars Orbiter Camera (MOC) and their highest ground resolution was 1 m/pix. It is enough to resolve large southern fans, but just not enough for the northern smaller ones! Only when HiRISE came around and imaged northern dunes, we saw that there are blotches and fans too. So, why the scales of them are so different? There might be several explanations. Below I will offer you one, which is probably the first to think about.

Martian seasons in southern and northern hemispheres are not equal.

Mars has elliptical orbit, its eccentricity is 0.0934 (e = 0 would be a circle). It is small, but in the planetary scale it takes Mars some 42 million kilometers closer to the Sun in its closest approach than in the furthest position on the orbit. The closest approach is called perihelion, from Greek “near the Sun”. It happens during summer in the southern hemisphere.

So, Mars is closer to Sun when it is summer in the south – this means during southern summer it gets more solar energy than during northern. Unlike our Earth, Mars does not have a huge water reservoir of the oceans to dampen temperature variations. These 2 facts together lead to that southern summer is hotter than the northern. But how does this affects what happens in spring? In two ways: first, the amplitude of change from cold dark winter to hot bright summer is larger in the south. And second: Mars is moving faster on its orbit when it is closer to perihelion. So the changes happen faster!

Every day in spring the amount and strength of sunshine increases. In the north this increase is steady but slow. It probably makes seasonal ice layer subliming steadily from the top faster than creating under-ice gas cavities that burst and create cold CO2 jets and associated fans. While in the south every day energy increase is more like a jump: getting these bursts makes for higher probability of under-ice explosions. And lets us observe beautiful fans!

Meet the Team: Darren McRoy

Today we have the next installment of our Meet the Planet Four Team series, featuring Darren McRoy from the Zooniverse team.


Name: Darren McRoy

What is your current position and where/institution?

I am currently the Zooniverse Community Builder at the Adler Planetarium in Chicago, IL.

Where are you originally from/where did you grow up?

I was born in Beverly, MA, and raised in Andover, MA. I moved to IL to attend Northwestern University, starting in 2006.

In 3 lines explain what you do as part of the Zooniverse development team?

My primary role is to be a liaison with our citizen science community as we continue to expand the Zooniverse in exciting new directions. I also assist in general communications efforts, such as producing and editing written content for projects. Currently, I am working closely with our designers and developers on the next generation of Zooniverse’s Talk discussion system.

Why do you find interesting about Mars?

Both the possibility of human habitation and the incredible barriers that exist towards making it a reality.

What is your favorite movie?

Airplane! (1980)

What is your favorite book?

Catch-22 by Joseph Heller (1961)

What is the song you currently can’t get out of your head?

“And Then There Was Silence,” Blind Guardian, A Night at the Opera, 2002

 What three albums would you bring with you to a desert island?

Land of the Free, Gamma Ray, 1995

The River, Bruce Springsteen, 1980

Thriller, Michael Jackson, 1982

Favorite cocktail or beverage?

Any witbier/Belgian white beer

One Mars Year of Planet Four

Mars takes 687 day to complete one revolution in its orbit around the Sun, nearly twice as long as on Earth.  We launched Planet Four on January 8, 2013 and today marks one full Mars year of Planet Four. Happy 1st Mars year birthday to Planet Four!

To celebrate and to thank you for all your contributions to Planet Four since launch, we’ve made a poster using all of your names*


The full poster can be downloaded here (it’s big  – 22 MB download!), and a smaller resolution version (2 MB download) can be found here. You can find the original  image used to make the poster here.  It’s a subimage made by the HiRISE team from this newly released Inca City Season 5 image. We picked this image because of all the activity shown.  Fans and blotches galore! Did you find your name?

Thanks for all your clicks over this Martian year. The science team is working hard on finishing the first paper based on your classifications. We’re almost there, and plan to submit in early 2015. We couldn’t do this without your time and effort.

Help celebrate Planet Four’s first Mars year anniversary by mapping fans and blotches in HiRISE images today at

*Names are only shown for volunteers who gave permission for us to show their name on the Zooniverse account settings. To update your settings login to and update the ‘name’ field.

Spring 5 in Inca City

The HiRISE camera right has been taking observations looking for activity on the Martian South Pole over the past few months as part of the new monitoring season (Season 5). In August, we partnered with the HiRISE team for a public vote to determine which polar region would have its first observation prepared for public release. The region dubbed ‘Inca City’ won. We have a big surprise. Not just one image, but all currently available observations this season of Inca City were publicly released by the HiRISE team. That’s right 5 brand new images of Inca City were recently released! You can find these images at:

(If you’re looking to make your computer more Planet Four-themed, each of the links above have versions of the images formatted to be computer desktop backgrounds.)

Today, we have a post by  Planet Four Principal Investigator Candy Hansen telling tell you more about these observations:

It is southern spring again, and once again we are taking images of our favorite locations. We return to the same sites so that we can study processes from year-to-year. Do spring processes always play out similarly? Or do the occasional dust storms affect when fans appear and the pace of seasonal activities?

This location is known informally as Inca City. As citizens of Planet Four you already know that a seasonal polar cap composed of CO2 ice (dry ice) forms every winter. In the spring the ice sublimates from the top and the bottom of this layer of ice, and under the ice the trapped gas builds up pressure. Eventually a weak spot in the ice ruptures, and the gas escapes, carrying material from the surface with it. The material is deposited on the top surface of the ice, forming the fans and blotches that you have been measuring.


Inca City has distinctive ridges, one of which is shown at the top of this series of cutouts. The first cutout on the left was the first image to be taken after the sun rose, marking the end to polar night. We label time on Mars by “Ls”, which indicates the position of Mars in its orbit. Spring officially starts on Ls = 180, so at Ls = 174 there is very little sunlight. In spite of the small amount of sunlight seasonal activity has already started, and fans can be seen emerging from “spiders”, known formally as “araneiforms”.

These images have not been map-projected yet, so use the black arrow pointing at one of the spiders to orient the same locations from image to image. In the second image from the left, taken about 2 weeks later, you can see that the fan from that spider has become more prominent. In the araneiforms above so much dust has blown out that the individual fans seen in the leftmost image have begun to merge. The ridge is peppered with small spots where the seasonal ice has ruptured (blue arrow). Near the bottom of the second image there are new fans associated with boulders. Below that, at the bottom of the image, four new rupture sites have fans going in multiple directions.

The differences between the second and third images from the left are not substantial. That is because the time difference between the two is just 6 days, or “sols”. Fans on the ridge have lengthened just a bit, possibly due to fine material sliding downslope. In the fourth image from the left, taken at Ls = 191, the fans covering the araneiforms and on the ridge slope appear grey – are fine particles sinking into the ice? At the bottom of the image distinctive bright bluish fans are apparent.

Look at the boxed area in the 5th image and compare it to that same area in the 4th image, just below the indicated spider. The bland surface in the 4th image is now cracked. Polygonal cracks typically occur at this time in the spring. There are no easily-ruptured weak spots, so the pressure of the gas below the ice simply cracks the large plate of ice. The ice must have thinned to the point at which this pressure can break the ice sheet. Once it has cracked the gas escapes and new fans emerge, aligned along the cracks.

The ice has continued to thin by the time of the 6th image, and the araneiforms have likely defrosted entirely. More small fans emerge from cracks in the ice.

That’s not Mars!

Credit: NASA/JPL/University of Arizona

Credit: NASA/JPL/University of Arizona

The image above taken by HiRISE isn’t of the South Pole of Mars or any region on Mars for that matter. It’s an interloper from the Oort cloud (reservoir of the long period comets) coming in for a close encounter to Mars on its way into the inner Solar System for its closet approach to the Sun. This icy planetesimal originated in the Oort cloud and was perturbed onto an orbit that has slowly brought it into the inner Solar System and on a path that brings the comet close to Mars. So close in fact (87,000 miles away from Mars) that this is closer than any comet has come to Earth since the dawn of modern astronomy. This provided a rare opportunity to study this icy remnant of planet formation up close and personal with the flotilla of spacecraft orbiting Mars.

HiRISE, is the highest resolution camera sent to to the Red Planet, and the images you see on Planet Four come from it. HiRISE is designed to taken observations staring below at Mars. It’s a push broom camera so it’s using the motion of the spacecraft (Mars Reconnaissance Orbiter, MRO) its aboard  to create the image. To observe a comet requires a whole different way of observing using MRO to point and slew to target the comet. This was no easy feat but the HiRISE team accomplished it, taking images of the comet several days before and shortly before cloest encounter. During the closest part MRO was behind Mars to shield it and its instruments (including HiRISE) from the large amounts of dust entering the Martian atmosphere and could possibly damage or destroy the onboard instruments. This is likely the best optical image of Comet C/2013 A1 Siding Spring, we’ll have. It may look blurry and span only  a few pixels, but observations like this will significantly constrain the size of the nucleus. Congratulations to everyone involved for making these challenging observations successful.

This is the only the second comet imaged by HiRISE. HiRISE has tried this previously observing Comet ISON, a sun-grazing comet that broke up shortly before or during its encounter with the Sun. HiRISE imaged ISON’s nucleus and was able to put the best size constraints on the comet (better than the limits from the Hubble Space Telescope), that placed it around 1 km or smaller. With that size, ISON would be predicted not to survive matching the observations. The cool thing about both Siding Spring and ISON is that these comets were discovered with at least a year’s notice before their closest approach giving astronomers and planetary scientists time to apply for telescope time and mobilize resources (including spacecraft orbiting Mars!) to observe these elusive objects.

You can read more about these HiRISE observations here and here.  If you’re interested in hearing more about observations like this get undertaken by HiRISE and the team behind the camera check out this Planet Four Live Chat where we had discussing the preparations for the Comet ISON imaging with Kristin Block  and Christian Schaller. For a summary of all the Comet Siding Spring observations taken by the spacecraft orbiting Mars check out this blog by the Planetary Society’s Emily Lakdawalla.

Meet the Team: Andy Martin

Today we have the next installment of our Meet the Planet Four Team series, featuring Andy Martin one of our Planet Four Talk moderators.


Name: Andy Martin

Where are you originally from/where did you grow up? 

Horndean in Hampshire, now own and run a campsite in Bude, Cornwall

What drew you to participate in Planet Four?

Being able to get up close and personal with the surface of another world

What is your role as a Planet Four Talk moderator?

I guess it’s to help people find their way around at Planet 4, answer the questions they have, which I only know the answers to because I asked the same thing when I started out. Hopefully we can encourage them to get involved and not be afraid to post, ask questions and put up their own theories about how things work. And of course I’ve got plenty of questions of my own to post ;-)

What do you find interesting about Mars?

What i really like about the Planet4 project is that we are looking at what is still pretty much an unexplored world. There’s lots to look and wonder at, more questions than answers and no-one yet has the definitive line on everything going on with regard to the seasonal fans.

What is your favorite movie?

Animal House

What is your favorite book?

Lord of The Rings is the one I read again and again,

What is the song you currently can’t get out of your head?

The Dahlmanns cover of Amy Rigby’s “Dancing with Joey Ramone”, but I also have a repeat of 2 lines from James – Sit Down running through my head “If I hadn’t seen such riches, I could live with being poor”

What three albums would you take with you to a desert island?

Ohh toughie – Live albums any one from The Ramones – It’s alive/Green Day – Bullet in a Bible/Thin Lizzy – Live and Dangerous ; Wreckless Eric – Greatest Stiffs; Eddie and the Hot Rods – Teenage Depression

Favorite cocktail or beverage?

Youngs Double Chocolate Stout

Meet the Team: John Keegan

Today we have the next installment of our Meet the Planet Four Team series, featuring John Keegan one of our Planet Four Talk moderators.

JK Outdoors
Name: John Keegan

Where are you originally from/where did you grow up?

I was born in Rochdale, Lancashire. For the last 30 years I’ve lived in the hills of Todmorden, West Yorkshire.

What drew you to participate in Planet Four?

The opportunity to help produce ‘weather maps’ on Mars was too good to miss, but if I’m really honest then I’ve got to admit I was lured by the fabulous HiRISE images on display.

What is your role as Planet Four Talk moderator?

I see myself as something of a ‘tour guide’, answering questions and sharing what I have learnt here on Planet Four. I try to keep track of who’s discussing what, so that I can point visitors to discussions that may be of interest to them. I’ve also got a bit of a reputation as the P4 comedian, but judging by the groans of other visitors I’m not sure that’s working out too well.

What do you find interesting about Mars?

Just about everything I see on Mars is interesting in some way or another, but the ‘spiders’ are definately my favourite objects. I’m beginning to take a particular interest in spiders that form at the bottom of craters.

What is your favorite movie?

It’s a tie between Orwell’s ‘1984’ and ‘Copying Beethoven’ starring Ed Harris.

What is your favorite book?

Another tie, between Orwell’s ‘1984’ and Kepler’s ‘Harmonices Mundi’.

What is the song you currently can’t get out of your head?

‘You Really Got Me’ by the Kinks.

What three albums would you bring with you to a desert island?

All nine symphonies of Beethoven should fit on three albums.

Favorite cocktail or beverage?

Coffee with milk, no sugar, in a never ending stream.

Help Feature Planet Four on the Daily Zooniverse

Have you found an intriguing image you’ve classified on Planet Four? Have you come across a stunning fan field or an image with blue frost? Now’s your chance to have it featured on the Daily Zooniverse. The Daily Zooniverse blog  brings something new and different each and every day from across all the Zooniverse, and Grant and the Daily Zoonvierse team are  looking for contributions from volunteers  (including Planet Four’s Mars Explorers) to present.  Just add the hashtag #dailyzoo to an image’s Planet Four Talk page to nominate it. You can learn more here.

Meet the Team: Michael Aye

Today we have the next installment of our Meet the Planet Four Team series, featuring Michael Aye from the Science Team.


Name:  K.-Michael Aye

What is your current position and where/institution?

Postdoctoral Researcher at UCLA in Los Angeles, CA, Department of Earth, Planetary and Space Sciences 

Where are you originally from/where did you grow up?

I am from Germany, where I grew up approx 100 km northwest of Hamburg, near the North Sea.

What are your research interests/what do you work on?

  • Surface atmosphere interactions on Mars, creating visual phenomena that do not exist on Earth
  • Calibration of the Diviner radiometer instrument on-board the Lunar Reconnaissance Orbiter (LRO)
  • Automated image feature extraction using machine learning procedures

In 3 lines explain your PhD thesis?

I developed a calibration system for the photo-multiplier based cameras of the ground-based high energy gamma-ray telescope system H.E.S.S. This system was based on using nano-second short UV-laser pulses fluorescing a scintillator material and transporting that broader-band light through 50 m of fiber cables and have all this remote controllable. I finished up with installing and operating a LIDAR and radiometer to monitor the atmosphere status as required to cross-calibrate the observed gamma-ray flashes from the particle showers in the atmosphere.

Why are you interested in Mars?

Mars and Venus are the closest siblings of Earth and to understand their differences makes us understand Earth better (but I don’t like the multitude of Venusian chemistry that much.. yet ;) The lack of water on Mars really makes it a great lab for studying the interface between the surface and atmosphere because on Earth most of what we see is dominated by water-based erosion. On Mars, it’s the wind and amazing CO2 sublimation effects.

What is your favorite movie?

The Matrix

What is your favorite book?

I don’t have much time for reading anymore, but when I did, these books were big fun:

  • “Surely you’re joking, Mr. Feynman” (showing a bit too much hubris at times, but he was indeed a genius)
  • “Titan” from Steven Baxter (greatly informed S-F)
  • The robot novels of Isaac Asimov made me appreciate the complexity of connecting human language and interaction schemes to the operation of machines. It inevitably makes you think about the human consciousness definition as well. A must read for any S-F fan.

What is the song you currently can’t get out of your head?

“Get lucky” by Daft Punk

What three albums would you bring with you to a desert island?

  • “Love is the tender trap” by Stacey Kent. The most ingenious introduction to Jazz ever made. Soft, gentle, but with everything that ever was important for Jazz to make it less fringy but more popular. It was my intro to Jazz and I will never stop loving it. It has an absolute genius of a piano player as well.
  • “Gran Riserva” by dZihan & Kamien. Great electronic lounge for the long work nights. I basically wrote my PhD with it.
  • And now the surprise :) “Once more with feeling”, soundtrack to the musical episode of Buffy the Vampire slayer. Also a remnant of my PhD times, it shows the early genius of Joss Whedon to its fullest.

Favorite cocktail or beverage?

I wouldn’t be able to pick really favorites, but among them are Margaritas on hot days, Caipirinhas and Mojitos. And since my 4 year stay in good ol’ England, I really am loving ales of all kind.


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