In a recent study published in Nature Astronomy, a team of researchers from Cornell University examined bright spots beneath the south pole of Mars and hypothesize that they are the results of geologic layering, not liquid water. This study holds the potential to help us better understand the overall makeup of the Red Planet and how we might find liquid water on, or beneath, its surface.
"On Earth, reflections that bright are often an indication of liquid water, even buried lakes like Lake Vostok," said Dr. Dan Lalich, a Research Associate at the Cornell Center for Astrophysics & Planetary Science at Cornell University, and lead author of the study. "But on Mars, the prevailing opinion was that it should be too cold for similar lakes to form."
Using simulations with layers comprised of atmosphere, carbon dioxide (CO2) ice, water ice, and basalt, Dr. Lalich was able to create reflections with brightness levels that were equivalent to the actual observations made on Mars.
"I used CO2 layers embedded within the water ice because we know it already exists in large quantities near the surface of the ice cap," said Dr. Lalich. "In principle, though, I could have used rock layers or even particularly dusty water ice and I would have gotten similar results. The point of this paper is really that the composition of the basal layers is less important than the layer thicknesses and separations."
The researchers ascertained that the separation between layers and their respective thickness play a bigger role on the reflective properties than the composition of each layer.
"None of the work we've done disproves the possible existence of liquid water down there," Lalich said. "We just think the interference hypothesis is more consistent with other observations. I'm not sure anything short of a drill could prove either side of this debate definitively right or wrong."
Sources: Nature Astronomy
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