Archive | December 2014

Merry Fans of Manhattan

Season’s Greetings. From all of the Planet Four team to all of you on Earth and Mars, we wish you a very merry Earth solstice, Happy Holidays, and a very happy new Earth Year.


Image credit: NASA/JPL/University of Arizona

Image credit: NASA/JPL/University of Arizona

Another holiday treat released by the HiRISE team this December was a 3-D image or anaglyph of Manhattan taken in November. You can find the full image here.

If you throw your red and blue 3-D glasses on, you should see the troughs of the spiders channels with fans dotting the surface. With these observations planetary scientists can measure depths of the channels and slopes of terrain. These images are created by combining two images of the same location (called a stereo pair) where HiRISE was oriented at different angles to the surface. You can read about the details here.

And if you’re looking for a cocktail for your new year’s party – check out this year’s Zooniverse cocktail list including a Planet Four themed drink (the last door of the Zooniverse’s advent calendar)

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