Scientists have discovered new evidence suggesting that there could be liquid water in Mars – a major advance in our long-standing efforts to determine whether the Red Planet ever supported life.
The Cambridge University-led study provides the first independent evidence using non-radar data that there is liquid water beneath Mars’ south polar ice cap.
Dr Frances Butcher, second author of the study from the University of Sheffield, said in a statement: “This study gives the best indication yet that there is liquid water on Mars today because it means that two of the key pieces of evidence we would look for when the search for subglacial lakes on Earth have now been found on Mars.’
Scientists have uncovered new evidence suggesting there could be liquid water on Mars, a major breakthrough in our efforts to determine whether the Red Planet ever supported life.
“Liquid water is an essential ingredient for life, although that does not necessarily mean that life exists on Mars,” he added in his statement.
“To be liquid at such cold temperatures, the water below the south pole might need to be really salty, making it difficult for any microbial life to inhabit it.
“However, it does give hope that there were more habitable environments in the past when the climate was less unforgiving.”
The international research team, which also included scientists from the University of Nantes and University College Dublin, used spacecraft laser altimeter measurements of the shape of the ice sheet’s upper surface to identify subtle patterns in its height.
Dr Frances Butcher, second author of the study from the University of Sheffield, said in a statement: “This study gives the best indication yet that there is liquid water on Mars today because it means that two of the key pieces of evidence we would look for when subglacial lakes were searched for on Earth have now been found on Mars
The international research team, which also included scientists from the University of Nantes and University College Dublin, used spacecraft laser altimeter measurements of the shape of the ice sheet’s upper surface to identify subtle patterns in its height. ABOVE: The south polar cap of Mars is seen in the topographical analysis of the new study
They then showed that these patterns matched the computer model’s predictions of how a body of water below the ice sheet would affect the surface.
Mars has thick sheets of water ice at both poles, like Earth, that are roughly equivalent in combined volume to the Greenland ice sheet.
However, unlike Earth’s ice sheets, which have large subglacial lakes and water channels beneath them, Mars’ polar ice caps are thought to be completely frozen to their bedrock due to the frigid climate of the Red Planet. .
Temperatures on Mars average a chilling -81 degrees Fahrenheit, but can drop as low as -220 degrees Fahrenheit in winter at the poles.
The researchers’ results, published today in the journal nature astronomyit is in agreement with previous ice-penetrating radar measurements that were originally interpreted to show a potential area of liquid water beneath the ice.
Unlike Earth’s ice caps, which have large subglacial lakes and water channels beneath them, Mars’ polar ice caps are thought to be completely frozen to their bedrock due to the Red Planet’s frigid climate. Temperatures on Mars average a chilling -81 degrees Fahrenheit, but can drop as low as -220 degrees Fahrenheit in winter at the poles.
‘Gives hope that there were more habitable environments in the past when the climate was less unforgiving’ ABOVE: Residual scatter plots of the trend surface shown in Fig. 1d against modeled elevation changes within a radius of 20 kilometers from the center of the region of Mars containing the inferred water
“The combination of the new topographical evidence, the results of our computer model, and the radar data make it much more likely that there is at least one area of subglacial liquid water on Mars today, and that Mars must still be geothermally active to keep the water below the liquid ice sheet,’ explained Professor Neil Arnold, from the Scott Polar Research Institute in Cambridge, who led the research.
The team used a wide variety of techniques to examine data from NASA’s Mars Global Surveyor satellite of the surface topography of the portion of Mars’ south polar ice cap where the radar signal was identified.
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.
This is similar in scale to the ripples above subglacial lakes here on Earth.
The scientists then tested whether the observed rippling on the ice surface could be explained by liquid water in the bed.
They then ran computer simulations of ice flow that were tailored to specific conditions on Mars.
They then inserted a low-friction patch into the bed of the simulated ice sheet where water, if present, would allow the ice to slide and accelerate.
Their experiments generated ripples on the simulated ice surface that were similar in size and shape to those the team observed on the surface of the real ice sheet.
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.
The findings also suggest that magnetic activity occurred relatively recently in the planet’s subsurface to allow for enhanced geothermal heating needed to keep water in a liquid state.
“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.”
