Scientists have found that Mars was likely far wetter – and capable of supporting life – than we previously thought.
A new study, which simulated Martian meteorites to understand more about its ancient environment, suggests that our history of the planet's surface might be entirely wrong.
Until now, a specific mineral found in Martian meteorites was used as proof that the planet had an ancient, dry environment. But in fact it might have contained hydrogen, which may see the history of the Red Planet rewritten into one far more covered with water.
Water is thought to be one of the central building blocks and requirements of life, and any discovery of water vastly improves the chances that the planet was inhabited.
The study also found that the important material could help create phosphorous – another essential element for life on Earth, and perhaps on Mars.
Everywhere on Earth, wherever water is found then life is also found. And phosphorous is necessary for that life to come about.
In the study, scientists created a synthetic version of the mineral known as whitlockite. They then conducted shock-compression experiments on samples of the material, simulating the conditions of being thrown on a meteorite from Mars.
The material was then studied using X-rays to find its microscopic makeup. They found that whitlockite could become dehydrated from those shocks and form merrillite, which is commonly found in meteorites thrown to Earth from Mars but doesn't occur here naturally.
“This is important for deducing how much water could have been on Mars, and whether the water was from Mars itself rather than comets or meteorites,” said Martin Kunz, a staff scientist who worked on the studies of the samples.
“If even a part of merrillite had been whitlockite before, it changes the water budget of Mars dramatically,” said Oliver Tschauner, a professor who co-led the study with Christopher Adcock.
The “water budget” is central to the question of whether there was ever life on Mars. Whitlockite can be dissolved in water to make phosphorus – which is required to bring about life on Earth – and the material could therefore once have been abundant on the planet.
“The overarching question here is about water on Mars and its early history on Mars: Had there ever been an environment that enabled a generation of life on Mars?” Professor Tschauner said.
To simulate the effect of being thrown from Mars, scientists blasted the synthetic whitlockite samples with metal plates that were fired from guns at about 1,678 miles per hour and with huge amounts of pressure. That extreme situation was required to simulate the shock of being hurled the planets atmosphere.
“You need a very severe impact to accelerate material fast enough to escape the gravitational pull of Mars,” said Professor Tschauner.
Even still, those conditions lasted for only 100 billionths of a second. That was only about 1 per cent as long as the actual experience would be – meaning that the conversion to merrillite would be even more potent on Mars.
Scientists now hope to prove that the conversion had actually taken place, by studying the meteorites on Earth and looking for traces of water.
If they found it, it would add to the already huge evidence that Mars once flowed with water and might continue to do so today. In 2013, scientists announced that streaks on the planet's surface appear to be caused by flowing water, and late last year researchers said that they had found a huge underground body of water ice on the planet.
But the new research shows how the planet might have been covered in far more water than it is today. Many Martian meteorites appear to come from a period around 150 million to 586 million years ago, and are thrown onto the Earth from deep beneath the surface, meaning that they don't necessary reflect the recent geology on the Red Planet's surface.