Science & Technology

The “lake” hidden on Mars is more likely to be clay than water

New research may rest the theory that water is under the cap of Mars’ Antarctic.

Researchers report that a form of clay called smectite may explain the bright radar reflections under the cap of Mars’ Antarctic.

The scientific community has long been skeptical of water theory. Specifically, there are lakes and other bodies of water at the top of the polar regions of Mars, says Isaac Smith, an assistant professor of geospace science at the University of Lasond. Engineering at the University of York.

“Recent publications have wondered if it’s even possible to have liquid water,” he says.

Taken by NASA’s Mars Reconnaissance Orbiter, this image shows the ice sheet in the South Pole of Mars. The spacecraft has detected clay near this ice. Scientists have proposed that such clay is the source of radar reflections that were previously interpreted as liquid water. (Credit: NASA / JPL-Caltech / U. Arizona / JHU)

For research Geophysics Research LetterResearchers can use experimental and modeling work to better explain the radar observations that Smectite made with the MARSIS (Mars Altitude Radar Underground and Ionospheric Exploration) equipment onboard the European Space Agency’s Mars Express Orbiter. Demonstrated.

In addition, they found spectral evidence that smectite was present at the edge of the Antarctic crown.

Smectite A class of clay formed when basalt, a volcanic rock that makes up most of the surface of Mars, chemically decomposes in the presence of liquid water.

York researchers have measured radar properties of hydrated smectite at room temperature and very low temperatures. Suspicious radar characteristics are two numbers that represent the real and imaginary parts of the permittivity. Both numbers are important for fully characterizing the material, but the 2018 study used modeling that included only the real part of the dielectric value and did not consider a particular class of material, clay. did.

Once the experimental measurements were completed, the researchers used the code to evaluate the data. In these simulations, researchers found that frozen clay had enough numbers to cause reflections.

Jennifer Witten, a planetary scientist at the University of Tulane’s School of Global Environmental Sciences, analyzed MARSIS radar data and made high-power observations at the base of Antarctic stratified sediments, both in the assumed lake area and elsewhere. Has been identified.

“In the last few years, there have been some studies interpreting radar data to show that there is a liquid water lake beneath the Antarctic ice cap on Mars,” says Witten. “If true, it’s revolutionary in understanding Mars’ habitability, so I decided to test that hypothesis.”

MARSIS is a radar sounder device similar to a ground penetrating radar device, which transmits microwave wavelength energy toward the surface of the earth. The instrument then “listens” for the returned signal. The strength of the signal depends on the material through which the signal interacts, such as air, water, ice, and rock.

“Because liquid water is very good at reflecting energy lake It could be one scenario that produces a strong signal with MARSIS data, “says Whitten. “Our paper investigates other scenarios that may generate the same signal and concludes that clay is likely to be present under the ice cap given the situation on Mars today. ..

“I think this study offers a viable alternative. I can’t wait to see how the planetary science community is embracing it,” she says. “It’s exciting to be able to participate in such a lively debate, where various groups are rapidly publishing papers on this topic.”

Additional co-authors are from the University of Arizona, Cornell University, and Purdue University.

sauce: Tulane University

The “lake” hidden on Mars is more likely to be clay than water The “lake” hidden on Mars is more likely to be clay than water

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