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Scientists reconsidering a mysterious signal from the south pole of Mars have suggested a possible new explanation, and it doesn’t bode well for hopes of finding liquid water on the Red Planet.
In 2018, scientists used data from the European Space Agency Mars Express This was announced by the Earth’s Mars Advanced Radar and Ionosphere Sounding Instrument (MARSIS) They noticed a radar signal that could be interpreted as evidence of liquid water. This signal, a strange bright reflection, came from the south pole of Mars in a region known as Ultima Scopuli. Researchers studying the reversal now suggest that the signal did not come from the ice itself, or even from liquid water, but from the underlying geological layers made up of minerals and frozen carbon dioxide. In particular, it turns out that the thickness of these layers, and not what they consist of, creates a reflection of the other world.
on me a landDazzling reflections like these often come from liquid water. For example, subglacial lakes like Lake Vostok in Antarctica, which have been under more than two miles (3 kilometers) of ice for millions of years, are causing a radar signal as bright as those on Mars. However, the mere possibility of something like this happening on Mars does not guarantee the existence of liquid water.
Related: These dry ice glaciers are moving on Mars at its south pole
The research team used radar data from MARSIS, along with computer simulations, to investigate this mystery. Scientists simulated layers of ice and other materials, such as basalt rock that formed after ancient volcanic eruptions on Mars, to see how these materials interact with incoming light.
Because there is a huge amount of carbon dioxide frozen at the south pole of Mars, Cornell University planetary scientist and lead author Dan Lalish was sure to include layers of this ice in the simulations. One simulation in particular, using a layer of carbon dioxide ice and under water ice, showed that the separation and thickness of the layers determine the strength of the reflection.
Previous studies that Lalich worked on also found that certain minerals can also evoke a reversal like this. He believes that even the dusty ice layers on the Red Planet are capable of this. In either case, no liquid water is required to create the reflection.
said in statement. “The aim of this research is that the composition of the basal layers is less important than layer thickness and separation.”
The new research doesn’t mean there’s no chance that there’s liquid water somewhere on Mars.
“None of the work we’ve done refutes the possibility that liquid water exists there,” Lalish said. “We just think the interference hypothesis is more consistent with the other observations. I’m not sure anything less than exercise can prove either side of this debate definitively true or false.”
Whether it’s under a glacier or deep beneath the planet’s scorched red surface, water—and perhaps traces of life or—may still lurk somewhere.
The research is described in a paper published on September 28 natural astronomy (Opens in a new tab).
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