There is liquid water under Mars, new evidence suggests.
The find is a major breakthrough in the search for evidence that Mars is wetter than it appears – and by extension, the search for extraterrestrial life on the planet.
Scientists say the new results represent the first time evidence of water beneath the surface of Mars has been found using non-radar data. As such, it offers another clue that the Red Planet may be habitable.
Scientists warned that the finding “doesn’t necessarily mean life exists on Mars.” However, according to researchers, this suggests that there may have been a time when Nasa was more livable.
In the study, the researchers used lasers on spacecraft to identify small changes in the elevation of the ice caps on Mars. They then compared those patterns to a computer model that predicted how a body of water beneath those ice caps would alter the surface – and found they matched.
Scientists have already used radar to find data suggesting there may be water beneath the ice. However, these results have been criticized by some, who have suggested that the radar data could be explained in other ways.
Now the new results are separate evidence that Mars does indeed have liquid water beneath its south pole.
The work was led by the University of Cambridge and involved researchers from the University of Sheffield and the Open University. Their work is described in a new article, “Surface topographic impact of subglacial water below the south polar ice cap of Mars,” published in natural astronomy today.
Like Earth, Mars has thick water ice caps at both poles, with a total volume roughly equal to that of the Greenland Ice Sheet.
Underlying Earth’s ice sheets are water-filled channels and even large subglacial lakes, but those on Mars were until recently thought to be frozen solid to their beds due to the cold Martian climate.
dr Frances Butcher, co-author of the study from the University of Sheffield, said: “This study provides the best evidence yet that there is liquid water on Mars today, because that means we would be looking for two of the most important pieces of evidence in the search for subglacial lakes on Earth have now been found on Mars.
“Liquid water is an essential part of life, although it doesn’t necessarily mean life exists on Mars.
“To be liquid in such cold temperatures, the water under the South Pole may need to be very salty, which would make it difficult for any microbial life to inhabit.
“However, there is hope that more livable environments existed in the past, when climates were less forgiving.”
In 2018, scientists used the European Space Agency’s Mars Express radar to peer through the Martian ice cap. The area beneath the ice turned out to be highly reflective of the radar signals – leading scientists to believe it was evidence of liquid water.
But a series of studies that came after suggested that other materials might be just as reflective, and that water is less likely to be the cause of the reflections since it would need another heat source to stay liquid. Therefore, many scientists believed that more evidence was needed to suggest that it was really water.
Professor Neil Arnold of the Scott Polar Research Institute in Cambridge, who led the research, said: “The combination of the new topographical evidence, our computer modeling results 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 keep the water beneath the ice cap liquid.”
Additional coverage by Press Association
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