WATER that once flowed over the surface of Mars is now trapped within its crust, according to a Nasa-funded study.
The Red Planet was a warm, dry planet covered in lakes and oceans until about three billion years ago, when all of its liquid bodies vanished.
Oceans and lakes that once flowed on Mars may now be trapped under its surfaceCredit: Getty
Scientists previously believed that the water escaped into space, but the new research suggests it remains locked within minerals in Martian soil.
“We’re saying that the crust forms what we call hydrated minerals, so minerals that actually have water in their crystal structure,” Eva Scheller, lead author of the new paper in the journal Science, told news agency AFP.
Working with Nasa’s Jet Propulsion laboratory, the team at Caltech analysed the chemical makeup of Mars using meteorites and data from Mars rovers.
Their findings suggest that between 30 per cent and 99 per cent of the planet’s ancient water may still be found within the Martian crust.
A view from the ‘Kimberley’ formation on Mars taken by Nasa’s Curiosity rover. The layers of rock in the foreground dip towards the base of Mount Sharp, indicating flow of water toward a basin that existed billions of years agoCredit: Nasa
They showed that around four billion years ago, Mars was home to enough water to have covered the whole planet in an ocean up to 1,500m deep.
That’s about half the volume of Earth’s Atlantic Ocean.
A billion years later, however, the planet was covered by the dusty, dry landscape it has today.
Scientists had previously tried to explain that this loss was a result of water scaping into space due to Mars’ low gravitational pull.
Radar scans of the Red Planet uncovered evidence of underground lakes (blue) last yearCredit: Nature
However, the new research appears to show that such an escape cannot account for most of the water loss.
The study focussed on the presence of hydrogen – a key component in water.
There are two types of hydrogen, with about 0.02 per cent of the element’s atoms taking the form of deuterium, or “heavy hydrogen”.
The lighter-weight hydrogen – also known as protium – has an easier time escaping the planet’s gravity into space than its heavier counterpart.
Because of this, if most of the water on Mars had escaped Mars into space, it would have left a tell-tale signature.
Were that theory true, the ratio of deuterium to hydrogen would be higher in the crust than in the upper atmosphere.
Given how much water Mars is thought to have started with, and the current rate of hydrogen escape observed by spacecraft, the current deuterium-to-hydrogen ratio cannot be explained by atmospheric loss alone, researchers said.
Instead, it’s most likely that some water escaped into the atmosphere while a large portion was trapped in minerals in the planet’s crust.
Here’s what you need to know about the Red Planet…
- Mars is the fourth planet from the Sun
- It is named after the Roman god of war
- The landmass of Mars is very similar to Earth but due to the difference in gravity you could jump three times higher there than you can here
- Mars is mountainous and hosts the tallest mountain known in the Solar System called Olympus Mons, which is three times higher than Everest
- Mars is considered to be the second most habitable planet after Earth
- It takes the planet 687 Earth days to orbit the Sun
- So far, there has been 39 missions to Mars but only 16 of these have been successful
“Atmospheric escape clearly had a role in water loss,” Ehlmann, a planetary geologist at Caltech, said.
“But findings from the last decade of Mars missions have pointed to the fact that there was this huge reservoir of ancient hydrated minerals whose formation certainly decreased water availability over time.
“All of this water was sequestered fairly early on, and then never cycled back out.”
Scheller plans to continue examining the processes by which Mars’s surface water was lost to the crust using laboratory experiments.
“This work is standing on the shoulders of work that has gone for decades,” Scheller said.
“And more observational evidence has been leading us more and more toward thinking about the loss of water on Mars in new ways.”
Recent evidence has uncovered tantalising clues as to the presence of water on Mars.
In 2018, radar scans carried out by a Mars orbiter indicated that a large underground lake may lurk beneath the planet’s icy south pole.
Further radar surveys last year proved the existence of the lake, and unearthed evidence of three further subterranean ponds.
Water is a key component for life, and the findings bolstered theories that alien microbes may live on Mars today.
However, the subsurface lakes are thought to be extremely salty, making the likelihood that life can grow within them slim.
In other news, Nasa has announced that it is accepting applications for wannabe space explorers who wish to fire their names to the Red Planet.
Perseverance rover revealed stunning video and audio recordings from the surface of the Red Planet last month.
And, space geeks have revealed stunning 4k footage of Mars captured by Nasa’s Curiosity rover.
What do you make of the Mars find? Let us know in the comments!
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