Confirming liquid water beneath Martian south polar cap

A Southwest Research Institute scientist measured the properties of ice-brine mixture to confirm that there is salty water under the ice cap on Mars. The measurements conducted by Dr. David Stillman support the bright reflections detected by the MARSIS radar.

MARSIS flies over the planet, bouncing radio waves over a selected area and then receiving and analyzing the echoes or reflections. The radar signal for ice and rock would be much smaller than for liquid water.

Many scientists have questioned the presence of liquid water because models assume the Mars south polar cap experiences temperatures much lower than the melting point of water. Possible explanations for the bright reflections include clay, hydrated salts and saline ices. The Italian-led team used previously published data, simulations and new laboratory measurements to investigate the proposed phenomena.

There are lakes of liquid water underneath glaciers in the polar regions, so we have Earth analogues for finding liquid water below ice. We studied how these salts would respond to radar.

Stillman has over a decade of experience measuring the properties of materials at cold temperatures to detect and characterize ice, unfrozen water and the potential for life throughout the solar system. Stillman measured the properties of perchlorate brines in an environmental chamber that produces near-liquid-nitrogen temperatures at Mars-like pressures.

The Italian colleagues reached out to see if my laboratory experiment data would support the presence of liquid water beneath the Martian ice cap. This is similar to how salt in the water saturates sand at the shoreline, but at a lower temperature than the South Pole of Mars.

All known life requires water, so the search for it in the universe is for potential habitability.

It has led us to place so cold that life could not flourish.

The research was published in a journal.

More information: Elisabetta Mattei et al, Assessing the role of clay and salts on the origin of MARSIS basal bright reflections, Earth and Planetary Science Letters (2022). DOI: 10.1016/j.epsl.2022.117370 Journal information: Earth and Planetary Science Letters Citation: Confirming liquid water beneath Martian south polar cap (2022, January 25) retrieved 26 January 2022 from https://phys.org/news/2022-01-liquid-beneath-martian-south-polar.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.