NASA Discovers Salty Liquid Water Flows Intermittently on Mars Today, Bolstering Chance for Life

These dark, narrow, 100 meter-long streaks called recurring slope lineae flowing downhill on Mars are inferred to have been formed by contemporary flowing water. Recently, planetary scientists detected hydrated salts on these slopes at Hale crater, corroborating their original hypothesis that the streaks are indeed formed by liquid water. The blue color seen upslope of the dark streaks are thought not to be related to their formation, but instead are from the presence of the mineral pyroxene.

The image is produced by draping an orthorectified Infrared-Red-Blue/Green(IRB)) false color image on a Digital Terrain Model (DTM). This model was produced by researchers at the University of Arizona, much like the High Resolution Imaging Science Experiment (University of Arizona). The vertical exaggeration is 1.5.

NASA and Mars planetary scientists announced today (Sept. 28) that salty “liquid water flows intermittently” across multiple spots on the surface of today’s Mars – trumpeting a major scientific discovery with far reaching implications regarding the search for life beyond Earth and bolstering the chances for the possible existence of present day Martian microbes.

Utilizing spectroscopic measurements and imaging gathered by NASA’s Mars Reconnaissance Orbiter (MRO), researchers found the first strong evidence confirming that briny water flows on the Red Planet today along dark streaks moving downhill on crater slopes and mountain sides, during warmer seasons.

“Mars is not the dry, arid planet that we thought of in the past. Today we announce that under certain circumstances, liquid water has been found on Mars,” said Jim Green, NASA Planetary Science Director at NASA Headquarters, at a media briefing held today, Sept 28.

“When you look at Earth, water is an essential ingredient. Everywhere we go where there’s liquid water, whether its deep in the Earth or in the arid regions, we find life. This is tremendously exciting.”

“We haven’t been able to answer the question – does life exist beyond Earth? But following the water is a critical element of that. We now have great opportunities to be in the right locations on Mars to thoroughly investigate that,” Green elaborated.

“Water! Strong evidence that liquid water flows on present-day Mars,” NASA officials tweeted about the discovery.

The evidence comes in the form of the detection of mysterious dark streaks, as long as 100 meters, showing signatures of hydrated salt minerals periodically flowing in liquid water down steep slopes on the Red Planet that “appear to ebb and flow over time.”

The source of the water is likely from the shallow subsurface or possibly absorbed from the atmosphere.

Dark narrow streaks called recurring slope lineae emanating out of the walls of Garni crater on Mars. The dark streaks here are up to few hundred meters in length. They are hypothesized to be formed by flow of briny liquid water on Mars. The image is produced by draping an orthorectified (RED) image (ESP_031059_1685) on a Digital Terrain Model (DTM) of the same site produced by High Resolution Imaging Science Experiment (University of Arizona). Vertical exaggeration is 1.5.    Credits: NASA/JPL/University of Arizona
Dark narrow streaks called recurring slope lineae emanating out of the walls of Garni crater on Mars. The dark streaks here are up to few hundred meters in length. They are hypothesized to be formed by flow of briny liquid water on Mars. The image is produced by draping an orthorectified (RED) image (ESP_031059_1685) on a Digital Terrain Model (DTM) of the same site produced by High Resolution Imaging Science Experiment (University of Arizona). Vertical exaggeration is 1.5. Credits: NASA/JPL/University of Arizona

Water is a key prerequisite for the formation and evolution of life as we know it. So the new finding significantly bolsters the chances that present day extant life could exist on the Red Planet.

“Our quest on Mars has been to ‘follow the water,’ in our search for life in the universe, and now we have convincing science that validates what we’ve long suspected,” said John Grunsfeld, astronaut and associate administrator of NASA’s Science Mission Directorate in Washington.

“This is a significant development, as it appears to confirm that water — albeit briny — is flowing today on the surface of Mars.”

“This increases the chance that life could exist on Mars today,” noted Grunsfeld.

The data were gathered by and the conclusions are based on using two scientific instruments – the high resolution imaging spectrometer on MRO known as High Resolution Imaging Science Experiment (HiRISE), as well as MRO’s mineral mapping Compact Reconnaissance Imaging Spectrometer for Mars (CRISM).

The mysterious dark streaks of downhill flows are known as recurring slope lineae (RSL).

They were first detected in 2010 at dozens of sites on the sun facing slopes of deep craters by Lujendra Ojha, then a University of Arizona undergraduate student.

The new finding is highly significant because until today’s announcement, there was no strong evidence that liquid water could actually exist on the Martian surface because the atmospheric pressure was thought to be far too low – its less than one percent of Earth’s.

The flow of water is occasional and not permanent, seasonally variable and dependent on having just the right mix of atmospheric, temperature and surface conditions with salt deposits on Mars.

Portions of Mars were covered with an ocean of water billions of years ago when the planet was far warmer and more hospitable to life. But it underwent a dramatic climate change some 3 billion years ago and lost most of that water.

The RSL with flowing water appear in at least three different locations on Mars – including Hale crater, Horowitz crater and Palikir crater – when temperatures are above minus 10 degrees Fahrenheit (minus 23 Celsius). They appear during warm seasons, fade in cooler seasons and disappear during colder times.

Pure surface water ice would simply sublimate and evaporate away as the temperature rises. Mixing in surface salts lowers the melting point of ice, thereby allowing the water to potentially liquefy on Mars surface for a certain period of time rather than sublimating rapidly away.

“These are dark streaks that form in late spring, grow through the summer and then disappear in the fall,” said Michael Meyer lead scientist for the Mars Exploration Program at NASA Headquarters, at the media briefing.

Years of painstaking effort and laboratory work was required to verify and corroborate the finding of flowing liquid water.

“It took multiple spacecraft over several years to solve this mystery, and now we know there is liquid water on the surface of this cold, desert planet,” said Meyer. “It seems that the more we study Mars, the more we learn how life could be supported and where there are resources to support life in the future.”

The dark, narrow streaks flowing downhill on Mars at sites such as this portion of Horowitz Crater are inferred to be formed by seasonal flow of water on modern-day Mars. The streaks are roughly the length of a football field. These dark features on the slopes are called "recurring slope lineae" or RSL. The imaging and topographical information in this processed view come from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter.   Credit: NASA/JPL-Caltech/Univ. of Arizona
The dark, narrow streaks flowing downhill on Mars at sites such as this portion of Horowitz Crater are inferred to be formed by seasonal flow of water on modern-day Mars. The streaks are roughly the length of a football field. These dark features on the slopes are called “recurring slope lineae” or RSL. The imaging and topographical information in this processed view come from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter. Credit: NASA/JPL-Caltech/Univ. of Arizona

Along with the media announcement, the researchers published their findings today in a refereed scientific paper in the Sept. 28 issue of Nature Geoscience.

“We found the hydrated salts only when the seasonal features were widest, which suggests that either the dark streaks themselves or a process that forms them is the source of the hydration. In either case, the detection of hydrated salts on these slopes means that water plays a vital role in the formation of these streaks,” said Lujendra Ojha, now at the Georgia Institute of Technology (Georgia Tech) in Atlanta, and lead author of the Sept. 28 publication in Nature Geoscience.

The scientists “interpret the spectral signatures as caused by hydrated minerals called perchlorates.”

Ojha said the chemical signatures from CRISM were most consistent with the detection of mixtures of magnesium perchlorate, magnesium chlorate and sodium perchlorate, based on lab experiments.

“Some perchlorates have been shown to keep liquids from freezing even when conditions are as cold as minus 94 degrees Fahrenheit (minus 70 Celsius).”

Perchlorates have previously been detected in Martian soil by two of NASA’s surface missions – the Phoenix lander and the Curiosity rover. There is also some evidence that NASA’s Viking missions in the 1970s measured signatures of these salts.

On Earth concentration of perchlorates are found in deserts.

This also marks the first time perchlorates have been identified from Mars orbit.

Locations of RSL features on Mars
Locations of RSL features on Mars

NASA’s overriding agency wide goal is to send humans on a ‘Journey to Mars’ in the 2030s.

So NASA astronaut Mark Kelly exclaimed that he was also super excited about the findings, from his perch serving as Commander aboard the International Space Station (ISS), where he is a member of the first ever “1 Year ISS Mission Crew” aimed at learning how the human body will adapt to the long term missions required to send astronauts to Mars and back.

“One reason why NASA’s discovery of liquid water on #Mars is so exciting: we know anywhere there’s water on Earth, there’s some form of life,” Kelly tweeted today from on board the ISS, upon hearing today’s news.

The discovery of liquid water on Mars could also be a boon to future astronauts who could use it as a natural resource to ‘live off the land’ for sustenance and to make rocket fuel.

“If going to Mars on my Year In Space, I’d arrive soon to find water! H20 > rocket fuel, which means I could find my way back home too!,” Kelly wrote on his Facebook page.

“When most people talk about water on Mars, they’re usually talking about ancient water or frozen water,” Ojha explained.

“Now we know there’s more to the story. This is the first spectral detection that unambiguously supports our liquid water-formation hypotheses for RSL.”

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer

New Map Shows ‘Marsquakes’ Shook Wet Valles Marineris Sand, NASA Says

Mars today is a planet that appears to be mostly shaped by wind, but that wasn’t always the case. A new map adds information to the hypothesis that “marsquakes” affected at least a part of the planet’s vast canyon, Valles Marineris, while the area contained spring-filled lakes.

When the damp sand got shaken up, it deposited itself in hills. NASA says the new map, based on observations from the Mars Reconnaissance Orbiter (which you can see below), adds credence to the theory that it was water that made these deposits.

“The conditions under which sedimentary deposits in it formed have been an open issue for decades,” NASA wrote in a press release. “Possibilities proposed have included accumulation in lakebeds, volcanic eruptions under glaciers within the canyons, and accumulation of wind-blown sand and dust.”

The map you see below was created by the U.S. Geological Survey, which has more extensive information on the findings at this website. The observations also produced a suite of research in recent years, such as this 2009 paper led by Scott Murchie at the Johns Hopkins University Applied Research Laboratory.

Part of a map of Candor Chasma (part of Mars' Valles Marineris) based on observations from the Mars Reconnaissance Orbiter. Green is knobby terrain, pink is lobate deposits (ridged material) and blue "stair-stepped morphology" of hills and mesas. Credit: U.S. Geological Survey
Part of a map of Candor Chasma (part of Mars’ Valles Marineris) based on observations from the Mars Reconnaissance Orbiter. Green is knobby terrain, pink is lobate deposits (ridged material) and blue “stair-stepped morphology” of hills and mesas. Credit: U.S. Geological Survey

A Martian Blue Snake, Brought To You By Canadians And A Spacecraft

Here’s the awesome thing about space and social media: in some cases, you can often follow along with a mission almost as soon as the images come to Earth. A group of Canadians is taking that to the next level this month as they take control of the 211th imaging cycle of a powerful camera on the Mars Reconnaissance Orbiter.

While some images need to be kept back for science investigations, the team is sharing several pictures a day on Twitter and on Facebook portraying the views they saw coming back from the High Resolution Imaging Science Experiment (HiRISE) camera. The results are astounding, as you can see in the images below.

“It’s mind-blowing to realize that when the team, myself included, first look at the images, we are likely the first people on Earth to lay eyes upon a portion of the Martian surface that may have not been imaged before at such high resolution,” stated research lead Livio Tornabene, who is part of Western University’s center for planetary science and exploration.

The team will capture up to 150 images between Nov. 30 and Dec. 12, and already have released close to two dozen to the public. Some of the best are below.

Water Or Not? Fresh Martian Trenches Primarily Due To Carbon Dioxide Freezes, Study Says

Mars Reconnaissance Orbiter

Does liquid water currently flow on the surface of Mars? Fresh-looking trenches on the Red Planet have come under a lot of scrutiny, including a 2010 study concluding that 18 dune gullies were primarily formed by carbon dioxide freezing.

A new study looking at several more gullies comes to about the same conclusion. Researchers examined images of 356 sites, with each of these sites captured multiple times on camera. Of the 38 of these sites that showed changes since 2006, the researchers concluded site changes happened in the winter — when it’s too cold for any liquid water to flow.

This image covers a location that has been imaged several times to look for changes in gullies.  This is in the Terra Sirenum region, part of the southern highlands in the mid-latitudes.  Credit: NASA/JPL/University of Arizona.
This image covers a location that has been imaged several times to look for changes in gullies. This is in the Terra Sirenum region, part of the southern highlands in the mid-latitudes. Credit: NASA/JPL/University of Arizona.

“As recently as five years ago, I thought the gullies on Mars indicated activity of liquid water,” stated lead author Colin Dundas of the U.S. Geological Survey’s Astrogeology Science Center in Arizona.

“We were able to get many more observations, and as we started to see more activity and pin down the timing of gully formation and change, we saw that the activity occurs in winter.”

Observations were made using NASA’s long-running Mars Reconnaissance Orbiter mission, which has been in orbit there since 2006. The researchers said that these lengthy missions are important for examining and confirming findings, because they can revisit data over time and change their conclusions, as needed, as more evidence comes in. Pictures were taken by the High Resolution Imaging Science Experiment (HiRISE) camera.

A 164-yard (150-meter) wide swath of Martian surface at 37.7 degrees south latitude, 192.9 degrees east longitude shows gullies changing between passes of the Mars Reconnaissance Orbiter. The earlier image, at left, was taken May 30, 2007. Near the arrows on the image on right, which was taken May 31, 2013, is a "rubbly flow" near the channel's mouth. Credit: NASA/JPL-Caltech/Univ. of Arizona
A 164-yard (150-meter) wide swath of Martian surface. It shows gullies changing between passes of the Mars Reconnaissance Orbiter. The earlier image, at left, was taken May 30, 2007. Near the arrows on the image on right, which was taken May 31, 2013, is a “rubbly flow” near the channel’s mouth. Credit: NASA/JPL-Caltech/Univ. of Arizona

The first images of gullies in 2000 sparked speculation that liquid water could be responsible for changing the surface today. It’s true that Mars has water frozen in its poles, and observations with several NASA rovers show strong evidence that water once flowed on the surface. But, these trenches are unlikely to show evidence that liquid water is flowing right now.

“Frozen carbon dioxide, commonly called dry ice, does not exist naturally on Earth, but is plentiful on Mars. It has been linked to active processes on Mars such as carbon dioxide gas geysers and lines on sand dunes plowed by blocks of dry ice,” NASA stated.

“One mechanism by which carbon-dioxide frost might drive gully flows is by gas that is sublimating from the frost providing lubrication for dry material to flow. Another may be slides due to the accumulating weight of seasonal frost buildup on steep slopes.”

The team added that smaller features could be the result of liquid water, such as this recent study using MRO. It’ll be interesting to see what other data is churned up as the fleet of orbiters continues making observations, and other scientists weigh in on the results.

The work will be published in the journal Icarus.

Source: Jet Propulsion Laboratory

Curiosity Captured from Orbit Crossing Landing Ellipse Boundary – Martian Scenery from Above and Below

NASA has now released a breathtaking high resolution image of the rover Curiosity captured from Mars orbit coincidentally coinciding with her crossing the targeted landing ellipse just days after she marked ‘1 Martian Year’ on the Red Planet in search of the chemical ingredients necessary to support alien microbial life forms.

The orbital image was taken on June 27 (Sol 672) by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter (MRO) and clearly shows the rover and wheel tracks at the end of the drive that Sol, or Martian day.

You can simultaneously experience the Martian eye view of Curiosity from above and below by checking out our Sol 672 ground level photo mosaic – below. It’s assembled from raw images taken by the mast mounted navigation camera (Navcam) showing the rovers wheel tracks and distant rim of the Gale Crater landing site.

Curiosity treks across Martian dunes and drives outside landing ellipse here, in this photo mosaic view captured on Sol 672, June 27, 2014.    Navcam camera raw images stitched and colorized.   Credit: NASA/JPL-Caltech/Marco Di Lorenzo/Ken Kremer – kenkremer.com
Curiosity treks across Martian dunes and drives outside landing ellipse here, in this photo mosaic view captured on Sol 672, June 27, 2014. Navcam camera raw images stitched and colorized. Credit: NASA/JPL-Caltech/Marco Di Lorenzo/Ken Kremer – kenkremer.com

The six wheeled robot drove about 269 feet (82 meters) on June 27 traversing to the boundary of her targeted landing ellipse in safe terrain – approximately 4 miles wide and 12 miles long (7 kilometers by 20 kilometers) – for the first time since touchdown on Mars nearly two years ago on August 5, 2012 inside Gale Crater.

Curiosity celebrated another Martian milestone anniversary on June 24 (Sol 669) – 1 Martian Year on Mars!

A Martian year is equivalent to 687 Earth days, or nearly two Earth years.

1 Martian Year on Mars!  Curiosity treks to Mount Sharp in this photo mosaic view captured on Sol 669, June 24, 2014.    Navcam camera raw images stitched and colorized.   Credit: NASA/JPL-Caltech/Marco Di Lorenzo/Ken Kremer – kenkremer.com
1 Martian Year on Mars!
Curiosity treks to Mount Sharp in this photo mosaic view captured on Sol 669, June 24, 2014. Navcam camera raw images stitched and colorized. Credit: NASA/JPL-Caltech/Marco Di Lorenzo/Ken Kremer – kenkremer.com

The SUZ sized rover is driving as swiftly as possible to the base of Mount Sharp which dominates the center of Gale Crater and reaches 3.4 miles (5.5 km) into the Martian sky – taller than Mount Rainier.

During Year 1 on Mars, Earth’s emissary has already accomplished her primary objective of discovering a habitable zone on the Red Planet that contains the minerals necessary to support microbial life in the ancient past when Mars was far wetter and warmer billions of years ago.

To date, Curiosity’s odometer totals over 5.1 miles (8.4 kilometers) since landing inside Gale Crater on Mars in August 2012. She has taken over 165,000 images.

Curiosity still has about another 2.4 miles (3.9 kilometers) to go to reach the entry way at a gap in the treacherous sand dunes at the foothills of Mount Sharp sometime later this year.

Stay tuned here for Ken’s continuing Curiosity, Opportunity, Orion, SpaceX, Boeing, Orbital Sciences, commercial space, MAVEN, MOM, Mars and more planetary and human spaceflight news.

Ken Kremer

Um, You Can See a Car on Mars

First of all, I completely stole this headline from NASA engineer Bobak Ferdowski (AKA The Mohawk Guy) on Twitter. Second, this is just a great image of the Curiosity rover sitting on Mars, including views of its tracks and where it did a wheelie or two. Plus, where the rover now sits is a very intriguing region called “The Kimberly.” Curiosity will soon whip out its drill to see if it can find hints of organic material, which could be a biomarker — the holy grail of Mars exploration.

Find out why this is such an intriguing region in this video:

Source: HiRISE

Mars’ Dingo Gap Seen From Orbit and the Ground

Thanks to the Mars Reconnaissance Orbiter and the HiRISE camera, we have an orbital view of Dingo Gap, an opening between two low scarps which is spanned by a single dune. This gap and dune are visible both from the ground and from orbit. The Curiosity Mars rover has now crossed the gap and is continuing its travels toward enticing science destinations, including interesting veins and mineral fractures.

In the orbital image from HiRISE, the rover itself is not in this image as it was acquired before MSL landed. However, the imagery was likely used to help the rover team decide on the way to travel.

Below are more images of Dingo gap before and after the rover plowed its way through the sand.

The Curiosity rover looks back at the tracks it left after crossing through the Dingo Gap sand dune. Credit: NASA/JPL, Caltech. Via Doug Ellison on Twitter.
The Curiosity rover looks back at the tracks it left after crossing through the Dingo Gap sand dune. Credit: NASA/JPL, Caltech. Via Doug Ellison on Twitter.
The series of nine images making up this animation were taken by the rear Hazard-Avoidance Camera (rear Hazcam) on NASA’s Curiosity Mars rover as the rover drove over a dune spanning “Dingo Gap” on Mars. Image credit: NASA/JPL-Caltech
The orbital view of Gale Crater and the Dingo Gap region. Credit: NASA/JPL/University of Arizona.
The orbital view of Gale Crater and the Dingo Gap region. Credit: NASA/JPL/University of Arizona.
Curiosity looks back to ‘Dingo Gap’ sand dune after crossing over, backdropped by Mount Sharp on Sol 535, Feb. 5, 2014.  Hazcam fisheye image linearized and colorized.  Credit: NASA/JPL/Marco Di Lorenzo/Ken Kremer- kenkremer.
Curiosity looks back to ‘Dingo Gap’ sand dune after crossing over, backdropped by Mount Sharp on Sol 535, Feb. 5, 2014. Hazcam fisheye image linearized and colorized. Credit: NASA/JPL/Marco Di Lorenzo/Ken Kremer- kenkremer.
Curiosity’s view to valley beyond after crossing over ‘Dingo Gap’ sand dune. This photomosaic was taken after Curiosity drove over the 1 meter tall Dingo Gap sand dune and shows dramatic scenery in the valley beyond, back dropped by eroded rim of Gale Crater. Assembled from navigation camera (navcam) raw images from Sol 535 (Feb. 6, 2104) Credit: NASA/JPL-Caltech/Ken Kremer- kenkremer.com/Marco Di Lorenzo

Brand New Impact Crater Shows Up on Mars

The great thing about the longevity of the Mars Reconnaissance Orbiter is that we can see changes taking place on the Red Planet, such as this relatively new and rather large impact crater. This image shows a stunning 30-meter-wide crater with a rayed blast zone and far-flung secondary material surrounding. Scientists say the impact and resulting explosion threw debris as far as 15 kilometers in distance.

Before and after pictures of this region show the new impact crater formed between July 2010 and May 2012.

The image has been enhanced in false color and so the fresh crater appears blue because of the lack of reddish dust that covers most of Mars’ surface.

With MRO’s help, scientists have been able to estimate that Mars gets pummeled with about 200 impacts per year, but most are much smaller than this new one.

The usual procedure for finding new craters is that MRO’s Context Camera, or CTX, or cameras on other orbiters identify anomalies or dark spots that appear in new images and then MRO’s High Resolution Imaging Science Experiment (HiRISE) camera is targeted to follow up by imaging those dark spots in greater detail.

More info on this new image can be found here.

HiRISE Spots Curiosity Rover and Tracks from Orbit

Amazing, the things a birds-eye view allows you to see. Here’s a color image from the HiRISE camera on board the Mars Reconnaissance Orbiter showing the tracks of the Curiosity rover. In this most recent HiRISE image of the MSL rover, the tracks are visible from Yellowknife Bay to its location on 11 December 2013, several kilometers to the southwest. Even though some of these tracks are more than a year old, they are still visible.

As HiRISE team member Christian Schaller said via Twitter, “Take only pictures; leave only footprints.” In this case, HiRISE took the pictures while MSL left the footprints!

HiRISE principal investigator Alfred McEwen explained the image: “Curiosity is progressing from the bright dust-covered area to a region with a darker surface, where saltating sand keeps the surface relatively free of dust. The scenery seen by the rover will be getting more interesting as it progresses toward Mount Sharp.”

See a black and white image below, where you can actually see Curiosity, too:

Can you spot the Curiosity rover from orbit? Credit: NASA/JPL/University of Arizona.
Can you spot the Curiosity rover from orbit? Credit: NASA/JPL/University of Arizona.

See more details on these images, as well as get access to higher resolution versions at the HiRISE website. You can see a collection of images of Curiosity taken by HiRISE here.

Can You Spot the Future Location of the Utopia Planitia Shipyards in this New HiRISE Image?

The name of this large impact basin on Mars, Utopia Planitia, sounds idyllic. But it also strikes a warm place in the heart of any Trekkie, as in the future (at least in the Star Trek Universe) it will be the location of the facility where the original Starship Enterprise and its many incarnations will be built. While the majority of the Utopia Planitia Shipyards are in geosynchronous orbit of Mars, there are also facilities on the planet as well, according to the Utopia Planitia Yards Starship Guide website. Uptopia Planitia was “found to be the ideal location [for the Shipyard], and a number of planetary sites are developed along with an expansive orbital facility located in geosynchronous orbit directly above,” explains the site.

But back to the present and this beautiful image from the HiRISE camera on board the Mars Reconnaissance Orbiter.

What is striking about the image are the polygon-shaped patterns of troughs and large scallop-shaped depressions. Mike Mellon, writing on the HiRISE website explains that collectively, such landforms are referred to as “thermokarst,” which both point to a slightly warmer and wetter Mars in the past.

Writes Mellon:

Under the proper climate conditions ice may form and seasonally accumulate in a honeycomb network of vertical fractures that appear when ice-rich soil contracts each winter. On Earth this form of subsurface ice is called an “ice wedge.” Special conditions are needed for this ice to accumulate and develop into a large wedge, namely warm temperature and abundant surface water. A thick layer of thawed wet soil forms allowing water to percolate into the open contraction cracks within the permafrost beneath. Later, loss of this wedge ice, by for example sublimation, results in deep depressions marking the honeycomb network.

Likewise, the larger scallop depressions might point to a past climate of frozen ponds or local patches of windblown snow collected in hollows. These surface ice deposits could later be covered by the ever-shifting soils and dust. In either case, the currently bitter cold and dry climate of Mars is not conducive to forming either of these buried-ice forms. Therefore, these landforms point to a warmer, but still cold, climate in the geologic past.

This image just highlights why I’m such a big fan of the HiRISE camera: a gorgeous image of our neighboring planet that was taken just last month from a spaceship orbiting Mars RIGHT NOW that tells us more about the past, while giving hope for our potentially space-faring future.