No canals on Mars but scientists discover strongest evidence yet planet was once habitable capable of supporting life

Red Planet had at least one large freshwater lake with right sort of chemical make-up to support kind of mineral-eating microbes seen on Earth

Science Editor

Scientists have discovered the strongest evidence to date that Mars was once a habitable planet capable of supporting primitive microbial life-forms at some time in the past.

An international team of researchers has found that about 3.6 billion years ago Mars had at least one large freshwater lake with the right sort of chemical make-up to support the kind of mineral-eating microbes seen on Earth.

Studies carried out by Nasa’s Curiosity Rover have for the first time revealed the existence of a type of sedimentary rock known as mudstone which is likely to have been created by a large body of standing water that had existed for at least many thousands of years.

Although the scientists emphasised that they have not yet found the smoking gun that proves the past existence of life on Mars, they are jubilant about finding what they believe is solid evidence that the planet was capable of supporting microbial life at some point in the past.

“I think it’s a step change in our understanding of Mars. It’s the strongest evidence yet that Mars could have been habitable for ancient microbial life,” said Professor Sanjeev Gupta of Imperial College London and a member of Nasa’s Mars Science Laboratory Curiosity mission.

“This is dramatic. We have effectively found what was once a standing body of water and although we don’t know how long it was there for, liquid must have been stable on the Martian surface for at least thousands or even millions of years,” Professor Gupta said.

Previous studies indicated that water had once flowed freely on Mars. Satellite images showed the kind of ground erosion that could have been caused by fast-moving water. This was further supported last year when the Curiosity rover found the smoothly-eroded pebbles of a dried-up river bed.

However, scientists believe that fast-flowing water is not conducive for the origin of life and so have been looking for lakes or ponds of permanent standing water that could have provided a more stable, habitable environment for the first Martian life-forms.

Mudstones usually form under calm conditions by the very gradual build up over long period of time of very fine grains of sediment which settle layer by layer on top of each other on the bed of a lake or sea.

The six-wheeled Curiosity rover found the mudstones at a place known as Yellowknife Bay near to its landing site within the Gale Crater, a 150 kilometre-wide impact basin with a mountain at its centre. Nasa sent Curiosity on a detour from its planned exploration of the mountain at the centre of the crater to explore a “thermal anomaly” at Yellowknife Bay.

Curiosity drilled into the rock and tested its composition with instruments designed to analyse the chemical makeup of solids when they are heated and vaporised. The studies, published in the journal Science, revealed the presence of the vital elements of life, namely carbon, hydrogen, oxygen, nitrogen and sulphur.

The study also found that the relatively neutral acidity of the lake would not have prevented life from forming, that the water was not too salty for life and that it could have existed as a standing body of water long enough for life to form.

It is possible that the mudstone beds extend for hundreds of metres deep under the Martian surface, which would represent tens of millions of years of geological time, the study found.

“We can envisage many combinations of terrestrial microbes that would be suited to form a Martian biosphere founded on chemolithoautotrophy [mineral-eating microbes] at Yellowknife Bay,” the study concluded.

Texture of the 'snake' as seen by MAHLI on Sol 149 Texture of the 'snake' as seen by MAHLI on Sol 149 (AFP/Getty) Professor Gupta said: “It is important to note that we have not found signs of ancient life on Mars. What we have found is that Gale Crater was able to sustain a lake on its surface at least once in its ancient past that may have been favourable for microbial life billions of years ago.

“This is a huge positive step for the exploration of Mars. It is exciting to think that billions of years ago, ancient microbial life may have existed in the lake’s calm waters, converting a rich array of elements into energy,” Professor Gupta said.

“The next phase of the mission, where we will be exploring more rocky outcrops on the craters surface, could hold the key to whether life did exist on the red planet,” he added.

Start your day with The Independent, sign up for daily news emails
ebooks
ebooksA special investigation by Andy McSmith
  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating
and  

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Salesforce Developer

£50000 - £65000 per annum: Recruitment Genius: Due to continued business growt...

Recruitment Genius: Internal Sales Executive

£20000 - £22000 per annum: Recruitment Genius: An exciting opportunity has ari...

Recruitment Genius: Sales Executive

£20000 - £25000 per annum: Recruitment Genius: This is a fantastic opportunity...

Recruitment Genius: Finance / Accounts Manager

£25000 - £30000 per annum: Recruitment Genius: Well established and expanding ...

Day In a Page

The saffron censorship that governs India: Why national pride and religious sentiment trump freedom of expression

The saffron censorship that governs India

Zareer Masani reveals why national pride and religious sentiment trump freedom of expression
Prince Charles' 'black spider' letters to be published 'within weeks'

Prince Charles' 'black spider' letters to be published 'within weeks'

Supreme Court rules Dominic Grieve's ministerial veto was invalid
Distressed Zayn Malik fans are cutting themselves - how did fandom get so dark?

How did fandom get so dark?

Grief over Zayn Malik's exit from One Direction seemed amusing until stories of mass 'cutting' emerged. Experts tell Gillian Orr the distress is real, and the girls need support
The galaxy collisions that shed light on unseen parallel Universe

The cosmic collisions that have shed light on unseen parallel Universe

Dark matter study gives scientists insight into mystery of space
The Swedes are adding a gender-neutral pronoun to their dictionary

Swedes introduce gender-neutral pronoun

Why, asks Simon Usborne, must English still struggle awkwardly with the likes of 's/he' and 'they'?
Disney's mega money-making formula: 'Human' remakes of cartoon classics are part of a lucrative, long-term creative plan

Disney's mega money-making formula

'Human' remakes of cartoon classics are part of a lucrative, long-term creative plan
Lobster has gone mainstream with supermarket bargains for £10 or less - but is it any good?

Lobster has gone mainstream

Anthea Gerrie, raised on meaty specimens from the waters around Maine, reveals how to cook up an affordable feast
Easter 2015: 14 best decorations

14 best Easter decorations

Get into the Easter spirit with our pick of accessories, ornaments and tableware
Paul Scholes column: Gareth Bale would be a perfect fit at Manchester United and could turn them into serious title contenders next season

Paul Scholes column

Gareth Bale would be a perfect fit at Manchester United and could turn them into serious title contenders next season
Inside the Kansas greenhouses where Monsanto is 'playing God' with the future of the planet

The future of GM

The greenhouses where Monsanto 'plays God' with the future of the planet
Britain's mild winters could be numbered: why global warming is leaving UK chillier

Britain's mild winters could be numbered

Gulf Stream is slowing down faster than ever, scientists say
Government gives £250,000 to Independent appeal

Government gives £250,000 to Independent appeal

Donation brings total raised by Homeless Veterans campaign to at least £1.25m
Oh dear, the most borrowed book at Bank of England library doesn't inspire confidence

The most borrowed book at Bank of England library? Oh dear

The book's fifth edition is used for Edexcel exams
Cowslips vs honeysuckle: The hunt for the UK’s favourite wildflower

Cowslips vs honeysuckle

It's the hunt for UK’s favourite wildflower
Child abuse scandal: Did a botched blackmail attempt by South African intelligence help Cyril Smith escape justice?

Did a botched blackmail attempt help Cyril Smith escape justice?

A fresh twist reveals the Liberal MP was targeted by the notorious South African intelligence agency Boss