The Mists of Mars

This entry originally appeared as a guest post on The Planetary Society site.

Late last month, visitors to Grand Canyon National Park in Arizona witnessed a rare and spectacular sight. A temperature inversion (where a layer of cold air is trapped beneath warm air) led to a canyon filled to the brim with clouds.

Grand Canyon Inversion
Grand Canyon Inversion – A temperature inversion in November, 2013 created a rare sight for visitors to the Grand Canyon as the chasm filled with clouds. Credit: NPS / Erin Whittaker

On the very same day, a robotic spacecraft at the planet Mars captured a similar scene. This one was a much more common event, but one that still makes for incredible imagery. Valles Marineris is a network of canyons that in many ways looks similar to the Grand Canyon–except that at more than 4,000 kilometers in length, if it were on Earth it would stretch across most of the United States.

This canyon, too, sometimes fills with clouds, made of tiny particles of water ice, though it’s not caused by an inversion. Despite the Red Planet’s well-earned reputation as a dry desert, there are hints of water on its surface and in its atmosphere. The Mars Color Imager (MARCI) on board the Mars Reconnaissance Orbiter makes daily observations of the entire planet. On November 29 and 30, MARCI returned pictures of wispy clouds clinging to the summits of Olympus Mons and the other towering volcanoes. It also showed Valles Marineris, a long horizontal scar probably formed in part by the tectonic effects of all those volcanoes. As happens seasonally, the canyon was clearly filled with clouds.

The Clouds of Mars
The Clouds of Mars – A composite of global images of Mars taken on November 29-30, 2013 by the Mars Reconnaissance Orbiter. Water ice clouds cling to the summits of the major volcanoes, and fill the giant canyon of Valles Marineris (the long, horizontal feature in the south). Credit: NASA / JPL / Malin Space Science Systems / Bill Dunford

Some of the first detailed pictures of this phenomenon came from the Viking orbiters back in the 70s. This still-stunning capture shows the maze of canyons at the west end of Valles Marineris called Noctis Labyrinthus, “the labyrinth of the night,” as the morning sun vaporizes water that condensed in the shadows the previous night.

Water Ice Fog in Noctis Labyrinthus
– The canyons of Noctis Labyrinthus, on the west side of Valles Marineris, filled with water ice clouds in the morning sun. Captured by the Viking 1 orbiter. Credit: NASA / JPL

More recent missions bring us the same kinds of scenes in even more detail. Here, the Mars Express spacecraft’s high-res camera reveals a portion of the immense canyon haunted by haze.

Mist in the Canyon

– A mist of water ice crystals hangs in the “Grand Canyon of Mars,” Valles Marineris. Observed by the Mars Express orbiter. Credit: ESA / G. Neukum (Freie Universitaet, Berlin, Germany) / Bill Dunford

It’s enticing to imagine the view from the edge of a Martian cliff on such a day. Thanks to an unusual gift from the Grand Canyon, now it’s a little easier to do so. (Another temptation: picturing past eons when the skies on Mars might have been a little more blue.)

Morning Mist
Morning Mist – A cloud inversion in the Grand Canyon in November, 2013. Credit: NPS / Erin Whittaker

The Northern Reaches

This entry originally appeared as a guest post on The Planetary Society site.

I love maps of the planets. They remind me that the landscapes of Mars and Mercury are real places. You could wade along the shores of Titan yourself, listening to the splash your boots made as you walked (as long as they were really, really good boots). Planetary maps mark the retreating frontiers of knowledge: explorers filling in the blank spaces based on the deep space dispatches of robotic scouts. More than metaphor, though, they’re such physically beautiful things. Each one combines the work of dozens of scientists, through technical precision and artistry, into a visual record of discovery. The US Geological Survey even makes frame-able paper maps available for order. They offer a tactile, ink-and-paper way to experience the data sent home by distant spacecraft.

Here’s a particularly handsome example. It’s a map of the geological features of the Martian north polar region. It charts the northern plains and the wind-sculpted cap of water ice and seasonal carbon dioxide frost. It’s full of intriguing craters and canyons with evocative names, such as the craters Boola and Jojutla, named after towns in Guinea and Mexico.

mars polar map
Geologic Map of the Martian North Pole – A portion of a map prepared by the US Geological Survey, based on data from several Mars missions, showing the geological features of the Martian north polar region. According to its creators, this map is the first to record the pole’s entire observable stratigraphic record using the various post-Viking image and topography datasets. The full map and key can be found on the USGS web site at Credit: USGS / Kenneth Tanaka / Corey Fortezzo

The colorful regions on the map represent variations in the geological formations in the area. Its creators note, with justifiable pride, that their “geologic map of Planum Boreum is the first to record this feature’s entire observable stratigraphic record using the various post-Viking image and topography datasets released up until 2009. We also provide much more detail in the map over what was presented [in earlier maps], including some substantial revisions based on new data and observations. The available data have increased and improved immensely in quantity, resolution, coverage, positional accuracy, and spectral range, enabling us to resolve previously unrecognized geomorphic features, stratigraphic relations, and compositional information.”

The complete map, key, and all the other details can be found on the USGS web site.

As compelling as this map is, after poring over it I still want to “go” there. Luckily for me, a number of spacecraft are circling Mars now, all in polar orbits that provide perfect views of the ice caps. I dug through the data sent back by the Mars Express orbiter, and found this one.

mars north pole
Boreales Scopuli – The north polar cap of Mars and the spiraling network of troughs, hundreds of meters deep, known as the Boreales Scopuli. The full cap is roughly 1000km across. Imaged by ESA’s Mars Express orbiter. Credit: ESA / G. Neukum (Freie Universitaet, Berlin) / Bill Dunford

That semi-circular scarp toward the bottom of the image is intruiging. Wouldn’t it be great to take a closer look? Again, luckily for me there’s a spacecraft for that. Another look through another digital archive produced this: a view of the feature’s curving edge, seen in fine detail by the Mars Reconnaissance Orbiter.

Ice Cliff – A steep ice scarp hundreds of meters tall at the edge of the north polar cap of Mars. Imaged by the high resolution camera aboard the Mars Reconnaissance Orbiter. Credit: NASA / JPL/ ASU

And now we can see why Mars explorers are continually drawn to this region, too: layers and layers of Martian history preserved in the ice like the chapters of a book. You can find out much more about it in the USGS pamphlet that accompanies the North Pole map.

It’s an interesting thought experiment to imagine future maps of Mars. What details will they chart? How about “Habitats of Valles Marineris”? Maybe you’ll be able to order a paper version.


The Gems of Mars

This article first appeared as a guest post on The Planetary Society’s site.

The Mars Reconnaissance Orbiter carries some of the most powerful cameras ever sent into space. They routinely send home eye-popping postcards from the fourth planet.

But there’s more to Mars than meets the eye, and MRO’s instruments are good for more than pretty pictures. For example, what human vision can’t detect, CRISM can. The Compact Reconnaissance Imaging Spectrometer for Mars, CRISM for short, uses a technique called reflectance spectroscopy to “see” minerals on the Martian surface.

What it finds can be pretty interesting: signs of water, of course, but if that’s not enough–sometimes it actually detects gemstone. In this observation of a crater’s central peak, the pink areas represent concentrations of a form of hydrated silica better known on Earth as opal.

CRISM Finds Opal in a Martian Crater
CRISM Finds Opal in a Martian Crater – A CRISM image showing the minerals present in a Martian crater, overlaid on a height-exaggerated map. The pink areas correspond to deposits of opal. Credit: NASA/JPL/JHUAPL

Opal is an intriguing find for at least a couple of reasons. One is that opal, a non-crystalline form of silica, often has a high water content. Another is that on Earth, opals have often preserved fossils and other signs of biology.

Here’s a closer look at that crater, this time courtesy of the HiRISE camera, also aboard MRO.

Martian Crater Rich in Opal
Martian Crater Rich in Opal – The CRISM imaging spectrometer on board the Mars Reconnaissance Orbiter identified the minerals present in this crater south of Baldet Crater. Among them: a form of hydrated silica better known as the gemstone opal. The colors of the landscape don’t appear as they would to the human eye, because instead of the usual red, green, and blue components of photographs, this image comes from infrared, red, and blue/green sensors. Credit: NASA/JPL/University of Arizona

Most of the opal found in this crater is probably not of the quality you would use to make jewelry. But since it could potentially preserve the history of life on Mars, if you could retrieve a sample, it would be more valuable than the brightest diamond.

There’s more about CRISM on a new web site dedicated to the instrument and its discoveries. The site is active, even during the US government shutdown.

The next time you’re reminded that the birthstone for October is opal, consider that there are opals on Mars, just waiting to be exposed by a future geologist’s hammer so they can glimmer in the sun.

Space Robot Roundup

Kasai Valles
Kasai Valles in a new view from the Mars Express orbiter. Credit: ESA/DLR/FU Berlin (G. Neukum)

I disappeared into the mountains for a week with no Net access. When I got back I saw that I missed a blast of robotic space exploration news. It’s a reminder of how much is happening right now all across the Solar System.

Just in case you find it as useful as I did, I put together a compilation of news and milestones from the past 10 days. (Links open in a new window.)


IAU Approves New Names for Ten Major Fault Scarps on Mercury
“The International Astronomical Union (IAU) recently approved a proposal from the MESSENGER Science Team to assign names to 10 rupes, the long cliff-like escarpments that formed over major faults along which one large block of crust on Mercury was thrust up and over another.”
Johns Hopkins University Applied Physics Laboratory

Earth’s Moon

NASA’s GRAIL Mission Solves Mystery of Moon’s Surface Gravity
“NASA’s Gravity Recovery and Interior Laboratory (GRAIL) mission has uncovered the origin of massive invisible regions that make the moon’s gravity uneven, a phenomenon that affects the operations of lunar-orbiting spacecraft.”
Jet Propulsion Laboratory


Mars Exploration Rovers Update: Opportunity Departs Cape York, Breaks Apollo Record
“It was a merry and mighty month of May for the Mars Exploration Rover mission.”
The Planetary Society

Mars Rover Opportunity Trekking Toward More Layers
“Approaching its 10th anniversary of leaving Earth, NASA’s Mars Exploration Rover Opportunity is on the move again, trekking to a new study area.”
Jet Propulsion Laboratory

Pebbly Rocks Testify to Old Streambed on Mars
“Detailed analysis and review have borne out researchers’ initial interpretation of pebble-containing slabs that NASA’s Mars rover Curiosity investigated last year: They are part of an ancient streambed.”
Jet Propulsion Laboratory

NASA’s Curiosity Mars Rover Nears Turning Point
“NASA’s Mars Science Laboratory mission is approaching its biggest turning point since landing its rover, Curiosity, inside Mars’ Gale Crater last summer.”
Jet Propulsion Laboratory

Video: Rover Ready to Switch Gears
“NASA’s Curiosity rover switches to long-distance driving mode as she heads to Mount Sharp.”
Jet Propulsion Laboratory

Curiosity update, sol 295: “Hitting the road” to Mount Sharp
“There was a Curiosity telephone conference this morning to make an exciting announcement: they’re (almost) done at Glenelg and are preparing for the drive south to Mount Sharp. Allow me an editorial comment: at last!”
The Planetary Society

Photos: Mars north polar ice cap
“The north polar ice cap of Mars, presented as a mosaic of 57 separate images from the High Resolution Stereo Camera on ESA’s Mars Express.”
European Space Agency

Photos: The Floodwaters of Mars
“Dramatic flood events carved this impressive channel system on Mars covering 1.55 million square kilometres, shown here in a stunning new mosaic from ESA’s Mars Express.”
European Space Agency

Video: Ten Years at Mars
“New global maps of Mars released on the 10th anniversary of the launch of ESA’s Mars Express trace the history of water and volcanic activity on the Red Planet, and identify sites of special interest for the next generation of Mars explorers.”
European Space Agency


Cassini Finds Hints of Activity at Saturn Moon Dione
“From a distance, most of the Saturnian moon Dione resembles a bland cueball. Thanks to close-up images of a 500-mile-long (800-kilometer-long) mountain on the moon from NASA’s Cassini spacecraft, scientists have found more evidence for the idea that Dione was likely active in the past. It could still be active now.”
Jet Propulsion Laboratory

Cassini Sees Precursors to Aerosol Haze on Titan
“Scientists working with data from NASA’s Cassini mission have confirmed the presence of a population of complex hydrocarbons in the upper atmosphere of Saturn’s largest moon, Titan, that later evolve into the components that give the moon a distinctive orange-brown haze.”
Jet Propulsion Laboratory


Weather Report: Mars

Mars weather view
The Mars Reconnaissance Orbiter makes a daily, global map of the Red Planet’s surface and weather. Here, thick water ice clouds cling to towering volcanic summits on June 5, 2012. Credit: NASA/JPL/MSSS/Bill Dunford

Mars is synonymous with mystery and alienness. And yet…there is often something about it that reminds of home. One thing Mars shares with Earth is weather: not just wind and dust storms, but clouds that come and go with the seasons.

Astronomers have glimpsed changes stirring in the Martian atmosphere for generations, and wondered exactly what was happening. Now we can do better, a lot better. In fact, a daily global weather report comes down from Mars routinely, thanks to a camera on board the Mars Reconnaissance Orbiter (MRO).

The above scene from a particularly cloudy Martian day in June of last year was assembled by a team at Malin Space Science Systems, the company that built the Mars Color Imager (MARCI) camera that captures the daily global view from on board MRO. MARCI sends hundreds of images of the surface, which are then assembled into a mosaic and map projected onto a globe.

This image, like most of the global views, originally included a few small blank areas where data was lost or the spacecraft was performing a navigation maneuver. I’ve patched those areas in using data from days just before and after the main images were captured.

You can see a weekly animation of the latest Martian weather conditions on the Malin site.

Note: This post is also available at The Planetary Society web site, where I’m delighted to be a new guest blogger.