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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NASA’s HiRISE Camera Recently Imaged a Martian Dust Devil. But Why Study Them?

A recent dust devil on Mars captured by NASA's High Resolution Imaging Experiment (HiRISE) camera. (Credit: NASA/JPL-Caltech/UArizona)

NASA recently used its powerful High Resolution Imaging Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter to take a breathtaking image of a dust devil traversing Syria Planum on Mars. One unique aspect of dust devils is their shadows can be used to estimate their height, which have been estimated to reach 20 km (12 miles) into the Martian sky. Studying dust devils on Mars is a regular occurrence for the scientific community and can help scientists better understand surface processes on other planets. But with the atmospheric pressure on Mars being only a fraction of Earth’s, what processes are responsible for producing dust devils?

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There's a Crater on Mars That Looks Like a Bear

A bear on Mars? Credit: NASA/JPL-Caltech/UArizona.

Facial pareidolia is the human tendency or illusion of seeing facial structures in an everyday objects – such as seeing the “man in the Moon,” or the face of Jesus on a piece of toast. But here’s a newly found crater on Mars that might be a case of ‘bear-adoilia.’

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This Ice Cliff is One of the Few Places With Exposed Water ice in the Mid-Latitudes on Mars. It’s Probably Tens of Millions of Years old

An icy cliff face on Mars. Credit: NASA/JPL-Caltech/UArizona.

Because of the orbiters and landers that have studied Mars over the years, scientists have learned that water ice is very likely locked away just under the surface throughout the planet’s mid-latitudes. These regions – especially in the northern hemisphere — are mostly covered with smooth material and scientists suspect ice is just underneath.

But sometimes, images like this give one from the HiRISE (High Resolution Imaging Science Experiment) camera on the Mars Reconnaissance Orbiter, provides a glimpse of the ice that might be buried below the surface. This image shows a cliff jutting out of the normally smooth terrain, and the cliff is covered with bright ice.

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The Tharsis Region of Mars is Peppered With These Strange Pit Craters. Now They’ve Been Found Elsewhere

An Atypical Pit Crater in ancient terrain near Elysium Mons, as seen by the Mars Reconnaissance Orbiter. Credit: NASA/JPL-Caltech/UArizona.

Pit craters are found on solid bodies throughout our Solar System, including Earth, Venus, the Moon, and Mars. These craters – which are not formed by impacts — can be indications of underground lava tubes, which are created when the top of a stream of molten rock solidifies and the lava inside drains away, leaving a hollow tube of rock. If a portion of the roof of the tube is unsupported, parts of it may fall in, making a hole or a pit along the lava tube’s path.

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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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This Crater on Mars is Just a Couple of Years Old

A recently formed impact crater on Mars. Credit: NASA/JPL-Caltech/UArizona

Changes are always taking place on Mars, from factors like seasonal variations and wind. But there’s one other aspect that changes the surface of Mar quite often: impacts.

Here’s a new impact crater that was seen by the Mars Reconnaissance Orbiter. Exactly when the crater formed is not known, but this image was taken on July 24, 2020 and in a previous image of this site taken in 2018, the crater is not there.

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This is a Dust Avalanche on Mars

HiRISE Spots Slope Streaks Fanning Out on Mars Image Credit: NASA/JPL-Caltech/UArizona

For decades, scientists have observed dark landslides called slope streaks on Mars. First seen by the Viking orbiters in the 1970s, every orbiter mission since has observed them, but the mechanism behind the slope streaks has been hotly debated: could they be caused by water activity on the Red Planet, or are they the result of some sort of dry mechanics?

Turns out, the leading candidate is “dry.” But scientists with the Mars Odyssey mission have verified an additional culprit behind the slope streaks: carbon dioxide frost.

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