Scientists have found new evidence of liquid water on Mars. details here

London:

An international team of researchers has found new evidence for the possible existence of liquid water beneath Mars’ south polar ice cap.

The results, published in the journal Nature Astronomy, provide the first independent evidence that there is liquid water beneath the south pole of Mars using data other than radar.

The researchers, led by the University of Cambridge with participation from the University of Sheffield, used laser altimeter measurements from the spacecraft of the shape of the ice cap’s upper surface to identify subtle patterns in its elevation.

They then showed that these patterns matched computer model predictions of how a body of water below the ice cap would affect the surface.

This rainbow-colored map shows subterranean water ice on Mars. Cold colors stand for less than 30 centimeters below the surface; warm colors are over 60 centimeters deep.

Their results are consistent with previous ice-penetration radar measurements, which were originally interpreted as showing a potential area of ​​liquid water beneath the ice.

There has been debate about interpreting liquid water from the radar data alone, with some studies suggesting that the radar signal is not due to liquid water.

“This study provides the best evidence yet that there is liquid water on Mars today, meaning that two of the most important pieces of evidence we would look for when searching for subglacial lakes on Earth are now found on Mars said Frances Butcher, co-author of the study from the University of Sheffield.

“Liquid water is an essential part of life, although it doesn’t necessarily mean life exists on Mars,” Butcher said.

To be liquid in such cold temperatures, the researchers determined that the water beneath the South Pole may have to be very salty, which would make it difficult for any microbial life to inhabit it.

However, there is hope that more habitable environments existed in the past when climates were less forgiving, they said.

Like Earth, Mars has thick water ice caps at both poles, with a total volume roughly equal to that of the Greenland Ice Sheet.

However, unlike Earth’s ice sheets, which are underlain by water-filled channels and even large subglacial lakes, the polar ice caps on Mars were until recently thought to be frozen solid to their beds due to the cold Martian climate.

In 2018, evidence from the European Space Agency’s Mars Express satellite challenged that assumption.

The satellite has an ice penetration radar called MARSIS that can see through the southern ice cap of Mars. It showed an area at the base of the ice that strongly reflected the radar signal, which was interpreted as an area of ​​liquid water beneath the ice cap.

However, subsequent studies suggested that other types of dry matter that exist elsewhere on Mars could produce similar reflection patterns if they exist beneath the ice cap.

Given the cold climate conditions, liquid water beneath the ice cap would require an additional heat source, such as B. geothermal heat from the interior of the planet, at levels above what is expected for Mars today.

“The combination of the new topographic evidence, the results of our computer model, and the radar data makes 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 sustain the water.” under the ice cap liquid,” said Professor Neil Arnold of the Scott Polar Research Institute in Cambridge, who led the research.

On Earth, subglacial lakes influence the shape of the overlying ice sheet—its surface topography. The water in subglacial lakes reduces friction between the ice sheet and its bottom and affects the rate of ice flow under gravity.

This in turn affects the shape of the ice sheet surface over the lake, often producing a depression in the ice surface, followed by a raised area further downstream.

The team, which included researchers from the University of Nantes, University College Dublin and the Open University, used a range of techniques to examine data from NASA’s Mars Global Surveyor satellite on the surface topography of part of Mars’ south pole ice cap The radar signal has been identified.

Their analysis revealed a 10-15 kilometer long surface ripple, consisting of a dip and a corresponding ridge, both deviating by several meters from the surrounding ice surface.

This is similar in magnitude to wave action over subglacial lakes here on Earth. The team then tested whether the observed ripple on the ice surface could be explained by liquid water on the bottom.

They ran computer model simulations of ice flow fitted to specific conditions on Mars. Then they added a reduced bed friction patch to the simulated bed of ice sheets where water, if present, would slide and accelerate the ice.

The researchers also varied the amount of geothermal heat coming from the planet’s interior. These experiments produced ripples on the simulated ice surface that were similar in size and shape to those the team observed on the real ice cap surface.

The similarity between the model-generated topographic ripple and the spacecraft’s actual observations, along with previous ice-penetrating radar evidence, suggest there is a pool of liquid water beneath Mars’ south pole ice cap, the researchers said.

This magmatic activity occurred relatively recently in the subsurface of Mars to allow for the enhanced geothermal heating needed to keep the water in a liquid state, they added.

(Except for the headline, this story was not edited by NDTV staff and was published by a syndicated feed.)