Is water present on Mars? Scientists have been debating this question since at least the 18th century, when astronomer Giovanni Schiaparelli used a telescope to observe Mars and thought he saw canals. 

A new compelling study suggests that a large lake of water exists beneath Mars’ south polar ice cap. The study sheds new light on the subject, implying that there may be liquid water on Mars after all.

The science and other important information

The European Mars Express orbiter discovered in 2018 that the surface of the ice cap covering Mars’ South Pole dips and rises, implying that liquid water could be lurking beneath. However, not all scientists were convinced at the time. Mars is extremely cold, and for subglacial water to exist in liquid form on the planet, there must be a source of heat, such as geothermal energy.

Some researchers speculated at the time of the Mars Express discovery that the strange radar signal could be explained by something else, such as dry material beneath the ice caps. However, an international team of scientists led by researchers from the University of Cambridge recently used a different technique to investigate the ice-sheet-covered region and concluded that the presence of liquid water is the most likely explanation.

Using NASA’s Mars Global Surveyor satellite laser-altimeter measurements to map the topography, or shape, of the ice cap’s upper surface, the researchers discovered subtle patterns of height differences that matched computer model predictions for how a body of water beneath the ice cap would affect its surface, according to the study.

“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,” said Neil Arnold, professor at Cambridge Scott Polar Research Insтιтute and the study’s lead author, in a press release.

What’s the big deal?

While not everyone agrees that there is liquid water on Mars, if it is proven to exist beneath the Red Planet’s surface, it may give rise to hope for the existence of hardy microbial life on the Red Planet.

“Liquid water is an essential component of life, but this does not necessarily imply that life exists on Mars,” said Frances Butcher, the study’s second author. “In order to be liquid at such cold temperatures, the water beneath the South Pole may need to be extremely salty, making any microbial life difficult to inhabit.” It does, however, provide hope that there were more habitable environments in the past when the climate was less harsh.”

What comes next?

The data returning from Mars, both from orbital satellites and landers, is of such high quality that we can use it to answer extremely difficult questions about conditions on and beneath the planet’s surface. And scientists are employing the same techniques that they do on Earth.

Reference(s): Nature Astronomy journal