Martian Glaciers?

3D anaglyph image. A system of valleys in the southern highlands of Mars, located east of a crater called Huygens and north of Hellas Planitia. Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO. Click to enlarge.

August 7, 2020

Some speculate that it was ice that carved Mars.

As written previously, robotic wanderers traveling the surface, as well as satellite telescopes, are providing data for the “search for life” on Mars. Sources of water in the Solar System are considered a necessity if life is to be found off the Earth.

Water sustains life on this planet, so it is presumed that water is essential for the establishment and continuity of life elsewhere. The High Resolution Imaging Science Experiment (HiRise), for example, is examining Mars from space, searching for evidence that water exists, or that it once existed on the surface. It is hoped that they will find subterranean water in areas that are shielded from direct sunlight.

The annual mean temperature of Martian regolith is about -50 Celsius, so planetary scientists think that Mars is covered with a global layer of permafrost. It is far colder in the northern and southern latitudes – so cold that carbon dioxide gas freezes into a solid and blankets the terrain with dry ice. Therefore, any water “must be” bound up with thick icy soils or locked in frigid underground vaults, otherwise water-ice would sublime directly into vapor. Since ice rather than liquid water is thought to predominate, it “must be” Martian glaciers rather than Martian floods that excavated some of the anomalous terrain.

Previous reports suggested that subsurface ice exists in the high northern latitudes, near Arcadia Planitia. “The fact that the ice is so thick and widespread leads us to think it came into place during one of Mars’ past climates when it snowed a bunch, ice accumulated, was buried, and then preserved,” said Shane Byrne, one of the authors of the study.

According to a recent press release: “A large number of the valley networks scarring Mars’s surface were carved by water melting beneath glacial ice.”

Anna Grau Galofre from the University of British Columbia wrote:

“For the last 40 years, since Mars’s valleys were first discovered, the assumption was that rivers once flowed on Mars, eroding and originating all of these valleys.”

The ice is not directly observed by the research team. Rather, it is the shape of the topography, particularly the Martian valleys, that led them to conclude that massive amounts of water-ice might be found on Mars. In the 3D anaglyph image at the top of the page, bizarre polygonal structures, thousands of parallel “cracks”, and multiple terraces are clearly visible. The blackened areas are not the signs of ice and water, they are the signs of electric arcs.

Previous Pictures of the Day about Mars describe the signature of powerful electric arcs that once impacted the planet’s surface. The energy released by plasma discharges took the form of sinuous rilles, flat-floored craters, “railroad track” patterns in canyons and craters, intersecting gullies with no debris inside them, giant mesas with Lichtenberg “whiskers” and steep-sided ravines wending through landscapes dotted with circular uplifts.

If Mars was the scene of planetary lightning bolts and not ice moving across the surface, should similar observations on Earth be reconsidered?

Stephen Smith

The Thunderbolts Picture of the Day is generously supported by the Mainwaring Archive Foundation.

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