Researchers announce discovery of liquid water 'lake' on Mars

The water was discovered far beneath the deeply frozen ice cap at Mars’ South Pole

Researchers announce discovery of liquid water 'lake' on Mars

Mars' South Pole in the Planum Australe region

Italian researchers believe they have discovered a lake of liquid water on Mars.

Scientists have long been aware that the Red Planet was home to surface water in its ancient past – but, if verified, this would be the first time liquid water has been found to exist in the present day.

Detected using ground-penetrating radar, the water was discovered far beneath the deeply frozen ice cap at Mars’ South Pole.

The lake lies a mile beneath the Martian surface – and is believed to be well below freezing temperature. Researchers believe it is only in liquid form because it is extremely salty and under great pressure.

The discovery was made by Italian scientists from a range of different institutions studying data from the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) instrument on board the ESA’ (European Space Agency) Mars Express spacecraft.

MARSIS searches for ‘reflections’ by beaming down pulses of radio waves on the planetary surface.

The waves can penetrate deep below the surface and are ‘reflected’ back at different intensities by different compounds under the ground.

The instrument captured 29 profiles while passing over the Red Planet’s Planum Australe and found that certain areas turned up ‘very sharp and intense’ reflections.

In a video accompanying the article in the journal Science lead researcher Roberto Orosei said this only happens on earth when the instrument is pointed at sub-glacial water.

He said it took several years for the researchers to confidently conclude that they had discovered “a stable body of liquid water on Mars.”

Should the lake exist, as the researchers believe it does, it would be around 20km in diameter and least a metre deep – meaning it would be made up of tens of millions of litres.

Italian astrophysicist Roberto Orosei, right, meets the media during a press conference at the Italian Space Agency headquarters in Rome, 25-07-2018. Image: Gregorio Borgia/AP/Press Association Images

Scientist now need to look for similar signals elsewhere on the planet – and rule out all other explanations for the MARSIS readings.

The discovery will also fuel calls for more ambitious missions to Mars – potentially carrying a drill capable of reaching the water, similar to what has been done for sub-glacial lakes in Antarctica.

Any potential mission is a long way into the future however – as the technology to fly a robot capable of drilling so deep into the Red Planet does not yet exist.