Smectite looks like ordinary rock but was formed by water a long time ago. Smith and his team placed several samples of smectite in a cylinder designed to measure how radar signals interact with it.
He also froze the samples with liquid nitrogen to minus 50 degrees Celsius, a temperature close to the temperature at the south pole of Mars.
After freezing the samples, the team determined that the smectites’ response to radar signals almost exactly matched the MARSIS observations.
Next, the scientists examined whether smectites existed on Mars near where the original strong radar signals were spotted in 2018. They used data from the Mars Reconnaissance Orbiter, which carries an instrument on board, the Compact Imaging Spectrometer (CRISM), a Capable of detecting smectites on Mars. Metal map.
It paid off. Although the CRISM technology can’t see through the ice, the team found some small objects scattered across the surface near the ice sheet. So it seems likely that smectite was also below the surface and caused strong reflections there about 1.5 kilometers below the surface.
“Smectite is very common on Mars, and covers about half of the planet, especially in the southern hemisphere,” Smith said. “This fact, combined with the radar-reflecting properties of smectite at extremely low temperatures, makes them the most likely explanation for this mystery.” Therefore, according to the authors, there is no need to assume the presence of liquid water, which would require improbable amounts of heat and salts.
However, scientists had previously hoped to find lakes. Co-author Dan Lalish of Cornell University said: “Unfortunately, this is a little disappointing, because lakes under the ice sheet would be very exciting. However, we think the smectite hypothesis is more likely and more consistent with other observations.”
There is no way to confirm what the strong radar signals are without landing at the south pole of Mars and digging through miles of ice, which is currently impossible. But recent studies have offered plausible explanations that make more sense than liquid water.
“In planetary science, we often get closer to the truth in centimeters and centimeters,” Plott said. “The original study didn’t prove it was water, and these new studies don’t prove it wasn’t water. But we’re trying to narrow down the possibilities as much as possible to come to a consensus.”
studies Kholer on Plot, From Led by Pearson And led by smith Posted in Geophysical Resarch Letters. This article is based on press releases from NASA, Cornell University, and the Planetary Science Institute.
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