Scientists find fresh evidence of liquid water on Mars, in major breakthrough in search for life

Scientists caution that new findings do not ‘necessarily mean that life exists on Mars’ – but that it could have been more habitable than we realised

There is liquid water under Mars, fresh evidence has suggested.

The finding is a major breakthrough in the hunt for proof that Mars is more wet than it appears – and with it the search for alien life on the planet.

Scientists say that the new findings represent the first time that evidence of water under the Martian surface has been found using data that did not come from radar. As such, it offers a further suggestion that the red planet could be habitable.

Scientists cautioned that the finding “does not necessarily mean that life exists on Mars”. But it does suggest that there may have been a time when the planet was more habitable, according to researchers.

In the study, researchers used lasers on spacecraft to identify small changes in the height of the ice caps on Mars. They then compared those patterns with a computer model that predicted how a body of water underneath those ice caps would change the surface – and found that they matched.

Scientists have already used radar to find data that suggested there could be water beneath the ice. But those findings had been criticised by some who suggested the radar data could be explained in other ways.

Now the new findings are a separate piece of evidence that Mars does in fact have liquid water beneath its South Pole.

The work was led by the University of Cambridge and included scientists from the University of Sheffield and the Open University. Their work is described in a new paper, ‘Surface topographic impact of subglacial water beneath the south polar ice cap of Mars’, published in Nature Astronomy today.

Like Earth, Mars has thick water ice caps at both poles, roughly equivalent in combined volume to the Greenland Ice Sheet.

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

Dr Frances Butcher, second author of the study from the University of Sheffield, said: “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 searching for subglacial lakes on Earth have now been found on Mars.

“Liquid water is an essential ingredient for life, although it does not necessarily mean that life exists on Mars.

“In order to be liquid at such cold temperatures, the water beneath the south pole might need to be really salty, which would make 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.”

In 2018, scientists used the European Space Agency’s Mars Express’s radar to look through Mars’s ice cap. It found that the area underneath the ice reflected the radar signals strongly – leading scientists to suggest it was evidence of liquid water.

But a range of studies came after that suggested that other materials could be just as reflective, and that water was less likely to be the cause of the reflections given it would need another heat source to stay liquid. As such, many scientists believed that further evidence was needed to suggest that it really was water.

Professor Neil Arnold, from Cambridge’s Scott Polar Research Institute, who led the research, said: “The combination of the new topographic evidence, our computer model results 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 in order to keep the water beneath the ice cap liquid.”

Additional reporting by Press Association