There are Important Differences Between the Ice Caps on Mars

This image shows eroded channels near the Martian poles filled with bright frozen carbon dioxide, in contrast to the muted red of the underlying ground. Credit:NASA/JPL/University of Arizona

In the 17th century, astronomers Giovanni Domenica Cassini and Christian Huygens noted the presence of hazy white caps while studying the Martian polar regions. These findings confirmed that Mars had ice caps in both polar regions, similar to Earth. By the 18th century, astronomers began to notice how the size of these poles varied depending on where Mars was in its orbital cycle. Along with discovering that Mars’ axis was tilted like Earth’s, astronomers realized that Mars’ polar ice caps underwent seasonal changes, much like Earth’s.

While scientists have been aware that Mars’ polar ice caps change with the seasons, it has only been within the last 50 years that they have realized that they are largely composed of frozen carbon dioxide (aka. “dry ice”) that cycles in and out of the atmosphere – and questions as to how this happens remain. In a recent study, a team of researchers led by the Planetary Science Institute (PSI) synthesized decades of research with more recent observations of the poles. From this, they determined how the Martian poles differ in terms of their seasonal accumulation and release of atmospheric carbon dioxide.

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This Sure Looks Like the Movements of a Glacier Across Ancient Mars

HiRISE image showing rough terrain possibly shaped by ancient glaciers. Credit: NASA/JPL-Caltech/UArizona

It is a scientific certainty that Mars was once a much different place, with a denser atmosphere, warmer temperatures, and where water once flowed. Evidence of this past is preserved in countless surface features, ranging from river channels and alluvial deposits to lakebeds. However, roughly 4 billion years ago, the planet began to change into what we see today, an extremely cold and desiccated environment. Between all that, it is possible Mars experienced glacial and interglacial periods, which is evidenced by images like the one taken by the NASA Mars Reconnaissance Orbiter (MRO) shown above.

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Want to Live on Mars? Here's Where the Water is

Mineral map of Mars showing the presence of patches that formed in the presence of water. Credit: ESA

When crewed missions begin to travel to Mars for the first time, they will need to be as self-sufficient as possible. Even when Mars and Earth are at the closest points in their orbits to each other every 26 months (known as “Opposition“), it can take six to nine months for a spacecraft to travel there. This makes resupply missions painfully impractical and means astronauts must pack plenty of supplies for the journey. They will also need to grow some of their food and leverage local resources to meet their needs, a process known as In-Situ Resource Utilization (ISRU).

In particular, astronauts will need to know where to find water on the Red Planet, which is no small challenge. Luckily, the European Space Agency (ESA) has created a mineral map showing the locations of aqueous minerals (rocks that have been chemically altered by water). This map was created by the Mars Orbital Catalog of Aqueous Alteration Signatures (MOCAAS) project and took over ten years to complete. When it comes time to select landing sites for crewed missions to Mars (in the next decade and beyond), maps like this will come in mighty handy!

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This Bizarre Terrain on Mars is Caused by Water Ice and Carbon Dioxide

Spring fans and polygons on Mars, as seen by the HiRISE camera on the Mars Reconnaissance Orbiter. Credit: NASA/JPL-Caltech/UArizona.

From orbit, this landscape on Mars looks like a lacy honeycomb or a spider web. But the unusual polygon-shaped features aren’t created by Martian bees or spiders; they are actually formed from a ongoing process of seasonal change from created from water ice and carbon dioxide.

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These are Star Dunes on Mars, Formed When the Wind Comes From Many Different Directions

An amazing aspect of Mars that is captured in many HiRISE images is geologic diversity within a small area. This image, of a crater in the Tyrrhena Terra region, was targeted to look at the geologic aspects of possible clays detected with the CRISM instrument. Image Credit: NASA/JPL/UArizona

Missions to Mars are expensive, even orbiters. They’re there to do science, not take pretty pictures. But sometimes Mars’ beauty is captured inadvertently, usually with some science mixed in.

That’s the case with this picture of star dunes captured by the HiRISE camera on NASA’s Mars Reconnaissance Orbiter.

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Ice Peeks out of a Cliffside on Mars

This area, on the western edge of Milankovic Crater on Mars, has a thick deposit of sediment that covers a layer rich in ice. The ice is not obvious unless you look in color. In the red-green-blue images that are close to what the human eye would see, the ice looks bright white, while the surroundings are a rusty red. The ice stands out even more clearly in the infrared-red-blue images where it has a striking bluish-purple tone while the surroundings have a yellowish-grey color. The ice-rich material is most visible when the cliff is oriented east-west and is shielded from the sun as it arcs through the sky to the south. Image Credit: NASA/JPL/UArizona

The HiRISE (High-Resolution Imaging Science Experiment) camera on the Mars Reconnaissance Orbiter has captured another beauty. This time the image shows water ice peeking out from a cliffside on Mars. A layer of sediment obscures most of the ice, but fingers of it are visible.

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One Feature Mars has That we Don’t: Polar Megadunes

For fans of astrophotography, Kevin M. Gill needs no introduction. Even if you’re not up on the latest astronomical news and developments, chances are you’ve still seen some of his images over the years. From beautiful artist renditions to breathtaking photographs of far-off planets, Gill has covered it all. Among the latest images available on his official Flickr page are pictures of a unique feature on Mars: the Chasma Boreale Megadunes!

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Dusty Snow on Mars Could be Melting Just Below the Surface

Dust on Mars gets everywhere – including on top of ice deposited during one of Mars’ previous ice ages.  Just how that dust affects the ice is still up for some debate. Adding to that debate, a recent paper by researchers at Arizona State University and the University of Washington has laid out a map between the dust content of a glacier and the brightness of its ice.

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Dust Storms on Mars Continue to Make the Planet Drier

NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft celebrated one Earth year in orbit around Mars on Sept. 21, 2015. MAVEN was launched to Mars on Nov. 18, 2013 from Cape Canaveral Air Force Station in Florida and successfully entered Mars’ orbit on Sept. 21, 2014. Credit: NASA

Despite decades of exploration and study, Mars still has its fair share of mysteries. In particular, scientists are still trying to ascertain what happened to the water that once flowed on Mars’ surface. Unfortunately, billions of years ago, the Martian atmosphere began to be stripped away by the solar wind, which also resulted in the loss of its surface water over time – although it was not entirely clear where it went and what mechanisms were involved.

To address this, a team of scientists recently consulted data obtained by three orbiter missions studying the Martian atmosphere. In the process, they found evidence that the smaller regional dust storms that happen almost annually on Mars are making the planet drier over time. These findings suggest that storms are a major driving force behind the evolution of Mars’ atmosphere and its transition to the freezing and desiccated place we know today.

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How Old is the Ice at Mars’ North Pole?

Ice at the north pole of Mars is seen from orbit in this image captured by Mars Express in May 2014. Credit: ESA/DLR/FU Berlin/J. Cowart

On Earth, the study of ice core samples is one of many methods scientists use to reconstruct the history of our past climate change. The same is true of Mars’ northern polar ice cap, which is made up of many layers of frozen water that have accumulated over eons. The study of these layers could provide scientists with a better understanding of how the Martian climate changed over time.

This remains a challenge since the only way we are able to study the Martian polar ice caps right now is from orbit. Luckily, a team of researchers from UC Boulder was able to use data obtained by the High-Resolution Imaging Science Experiment (HiRISE) aboard the Mars Reconnaissance Orbiter (MRO) to chart how the northern polar ice caps’ evolved over the past few million years.

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