Scientists have discovered that reflections from the south pole of Mars may not be the sign of liquid water they were expecting.
Although there is water in many places on Mars, including the poles, the European Space Agency’s Mars Orbiter detected significantly bright reflections under a 1.4 kilometer thick formation of relatively pure water ice .
But computer simulations, generated by Cornell University researchers, suggest that another phenomenon, interference between the red planet’s geological layers, could be the real cause.
Strong reflections can be generated in these simulations without liquid water or other rare materials, making it unlikely that liquid water exists below the layered reservoir at the south pole of Mars.
The simulation consisted of layers made of four materials: atmosphere, water ice, carbon dioxide ice and basalt, with the computer monitoring the interaction of each layer with electromagnetic radiation.
The researchers found that three layers, made up of two layers of carbon dioxide separated by one of ice, could produce reflections like those seen on the planet.
“On Earth, such bright reflections are usually an indication of liquid water, even from buried lakes like Lake Vostok. [under the surface of the East Antarctic Ice Sheet],” Dan Lalich, research associate at the Cornell Center for Astrophysics and Planetary Science, said. “But on Mars, the prevailing view was that it would have to be too cold for similar lakes to form.
“I used layers of CO2 embedded within water ice because we know it already exists in large quantities near the surface of the ice layer. In principle, however, I could have used layers of rock or even ice especially powdery water and would have obtained similar results.
The discovery of water on Mars is vital because it could be an indicator of life, as well as a resource that humans could use to develop an outpost.
“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 can prove either side of this debate definitively right or wrong.”
Previous research published in January reinforces the idea that water is not present under the mast. “In order for the water to stay so close to the surface, both a very salty environment and a strong locally generated heat source are needed, but this does not match what we know about this region,” Cyril Grima, planetary scientist from the University of Texas Geophysics Institute, he said.
Volcanic rock, buried beneath the ice, seems a more likely explanation, as iron-rich lava flows on Earth can leave behind rocks that produce similar reflections, and it’s possible the same effect is happening on our neighboring planet.