The statement that “there is water on Mars” has been debated since the eighteenth century to the present day. More and more evidence points to the existence of liquid water under the Martian soil. Now, an international team of scientists led by the University of Cambridge is shedding new light on the matter, suggesting that there may indeed be liquid water under the ice at Mars’ south pole after all.
Moving south
Beneath the icy cap at the south pole of Mars, something is happening. This new work, published in the journal Nature Astronomy , suggests that liquid water is hiding under all that ice. Although we cannot yet confirm it definitively, new evidence is added to the existing ones. And, if liquid water is shown to exist beneath the ice caps, it will raise hopes of hardy microbial life on the Red Planet. “Liquid water is an essential ingredient for life, although it does not necessarily mean that life exists on Mars,” the authors state.
The researchers used spacecraft laser altimeter measurements (NASA’s Mars Global Surveyor ) of the shape of the ice sheet’s upper surface to identify subtle patterns in its height . Their analysis revealed a 10- to 15-kilometre-long surface ripple comprising a depression and a corresponding raised area, both of which deviate several meters from the surrounding ice surface. They then showed that these patterns match predictions from computer simulations of how a body of water below the ice sheet would affect the surface.
Their results agree with previous ice-penetrating radar measurements that were originally interpreted to show a potential area of liquid water beneath the ice.
More evidence
“The combination of the new topographical evidence, the results of our computer model, and the radar data make it much more likely that at least one area of subglacial liquid water exists on Mars today, and that Mars must still be geothermally active to keep the water below the liquid ice sheet,” explains Neil Arnold of the Scott Polar Research Institute in Cambridge, who led the research.
The similarity between the ripple produced by the computer model and actual observations from the spacecraft, along with previous ice-penetrating radar evidence, suggest that there is an accumulation of liquid water beneath the south polar ice cap of Mars. .
Unlike Earth’s ice sheets, which have large subglacial lakes and channels of water beneath them, the Martian ice caps are thought to be completely frozen to their bedrock due to the frigid climate of the Red Planet.
And the geometry of the ice fits exactly what one would expect if it had water underneath. Their findings support previous ice-penetrating radar measurements , which were initially interpreted to indicate the possibility of an area of liquid water beneath the ice.
In the simulations, the amount of geothermal heat emanating from the planet’s interior was also altered. These experiments produced ripples on the simulated ice surface that resembled those the team saw on the actual surface of the ice sheet in terms of size and shape.
Is it enough to prove that there is liquid water?
Not quite. There is much disagreement regarding the interpretation of radar data, with some studies arguing that the radar signal is not caused by liquid water but by clay minerals. But we are on the right track.
“The quality of the data coming back from Mars, both from orbiting satellites and landers, is such that we can use it to answer really hard questions about conditions on, and even below, the surface of the planet, using the same data. techniques that we also use on Earth,” said Arnold. “It’s exciting to use these techniques to discover things about planets other than our own.”
Referencia: Neil Arnold, Surface topographic impact of subglacial water beneath the south polar ice cap of Mars, Nature Astronomy (2022). DOI: 10.1038/s41550-022-01782-0. www.nature.com/articles/s41550-022-01782-0
