New Mars discovery throws cold water on hopes of finding life

By Isobel Williams via SWNS

The chances of life on Mars have shrunk as research has pushed the presence of water on the planet further into the past.

Mars has long been considered the main candidate for extraterrestrial life, due to it being the only other rocky planet precisely far enough from the sun to allow for liquid water to exist.

Now, a new study has suggested that the period where liquid water was present on the surface of Mars may have been shorter than previously thought meaning there was less time for life to develop.

The team from Utrecht University in the Netherlands discovered that the channel landforms called gullies, previously thought to be formed exclusively by liquid water, can also be formed by the action of evaporating CO2 ice.

The researchers explain that in Martian winters the CO2 in the air freezes, changing it directly from gas to ice and skipping the liquid phase.

They note that this process is similar to frost on Earth, where water vapor forms ice crystals and blankets the landscape in a white film.

Doctoral candidate and planetary researcher Lonneke Roelofs said: “The Martian atmosphere is 95 percent CO2.

“In winter, air temperatures drop below -120 degrees Celsius, which is cold enough for CO2 in the atmosphere to freeze.”

When warmer temperatures come this ice evaporates back into a gas, again skipping the liquid phase.

Roelofs explained: “We call that ‘sublimation’. The process is extremely explosive due to Mars’ low air pressure.

“The created gas pressure pushes sediment grains apart causing the material to flow, similar to debris flows in mountainous areas on Earth.

“These flows can reshape the Martian landscape – even in the absence of water.”

Scientists have long hypothesized that CO2 ice could be a driving force behind these Martian landscape structures.

The research team confirmed these hypotheses with their experiments in a so-called ‘Mars chamber’ which simulated the process under Martian conditions.

They discovered that the debris flows driven by CO2 ice under Martian conditions flow just as efficiently as the debris flows driven by water on Earth.

Roelofs added: “We know for sure that there was once water on the surface of Mars.

"This study does not prove the contrary. But the emergence of life likely needs a long period where liquid water was present.

“Previously, we thought that these landscape structures were formed by debris flows driven by water, because of their similarity to debris flow systems on Earth.

"My research now shows that, in addition to debris flows powered by water, the sublimation of frozen CO2 can also serve as a driving force behind the formation of these Martian gully landscapes.

“That pushes the presence of water on Mars further into the past, making the chance of life on Mars smaller.”

The researchers believe that their findings, published in the journal Communications Earth & Environment, could translate to processes on Earth, specifically in volcanoes, giving them a better understanding of terrestrial volcanic hazards.