For those hoping to find evidence of water on the surface of Mars and with it signs of life, a new piece of space geology will be greeted with disappointment.
It would appear that the water-like reflections across parts of the Martian surface are due to geological layering rather than being due to the presence of liquid. This insight into Mars’ watery reflections comes from Cornell University.
Astronomers now believe bright reflections beneath the surface of Mars’ South Pole are not necessarily evidence of liquid water, but instead geological layers. This is unlike on Earth, where reflections that are bright are often an indication of liquid water. This occurs even with buried lakes like Lake Vostok.
On Mars it is simply too cold for similar lakes to form. However, the bright reflections exist on the surface, and these required a scientific explanation.
To demonstrate that the surface was a geological phenomenon rather than water, the researchers created simulations with layers composed of four materials: Atmosphere, water ice, carbon dioxide ice and basalt.
Next, the researchers assigned each layer a corresponding permittivity. This refers to an intrinsic property of the material describing its interaction with electromagnetic radiation passing through it.
It was found that simulations using three layers two carbon dioxide layers, separated by a layer of dusty ice, produced reflections as bright as the actual observations. The thickness of the layers and how far apart they are, has a significant impact on reflection power than the composition of the layers.
This made sense layers embedded within the water ice it already exists in large quantities near the surface of the Martian ice cap. The researchers concluded that the composition of the basal layers is less important than the layer thicknesses and separations.
The research does not disprove the possible existence of liquid water within Mars, it simply discounts one area of the Martian surface that has been subject to speculation as potentially being composed of water.
Meanwhile, the search for liquid water on or within Mars continues and this has major implications for how the planet’s climate has evolved and perhaps the presence of life.
The research appears in the journal Nature Astronomy, titled “Explaining Bright Radar Reflections Below The South Pole of Mars Without Liquid Water.”
