Our Rover Could Discover Life On Mars – Here’s What It Would Take To Prove It
Claire Cousins, 6 Jan 18
       

Mars seen by Viking. NASA / USGS

Finding past or present microbial life on Mars would without doubt be one of the greatest scientific discoveries of all time. And in just two years’ time, there’s a big opportunity to do so, with two rovers launching there to look for signs of life – Mars2020 by NASA and ExoMars by the European Space Agency and Roscosmos.

I am helping to develop one of the instruments for the ExoMars rover, which will be Europe’s first attempt to land a mobile platform on the red planet. It will also be the first rover to drill into the martian crust to a depth of two metres.

But the rover will not be the first to look for evidence of life. The Viking landers sent by NASA in the 1970s carried experiments designed to so. They were ultimately unsuccessful, but provided a wealth of information about Mars’ geology and atmosphere that comes in handy now. In fact, exploration over the last half-century has shown us that early Mars was once a dynamic and potentially habitable planet.

ExoMars prototype rover. Mike Peel/wikipedia, CC BY-SA

While it is not completely impossible that life could exist on Mars today, ExoMars is primarily focused on looking for extinct life. Because there’s a risk it could contaminate the planet with microbes from Earth, it is not allowed to go near the sites where we think it’s possible that microbes could exist today.

Chemofossils are the best bet

On Earth, life constantly unfurls around us, leaving its mark on our planet every day. There are, however, a number of factors to contend with when looking for life on Mars. The first is that the lifeforms we are looking for are single-celled microorganisms, invisible to the naked eye. This is because life on Mars is unlikely to have progressed any further down the evolutionary path. This is actually not so strange – Earth itself was a world of single-celled life for two billion years or more.

Another issue is that the life we’re looking for would have existed three or four billion years ago. A lot can happen in that time – rocks preserving this evidence can be eroded away and redeposited, or buried deep beyond reach. Luckily, Mars does not have plate tectonics – the constant shifting about and recycling of the crust that we have on Earth – which means it’s a geological time capsule.

Because we are looking for evidence of long-dead microorganisms, the hunt for bio-signatures lies in the detection and identification of organic “chemofossils” – compounds that are left behind by the decomposition of life. These are different to organic compounds delivered to planets on the backs of meteorites, or those, such as methane, that can be produced by both geological and biological processes. No single compound will prove life once existed.

Sign in to view full article

       
Too Many Tabs – Why Some People Can Multitask Online and Others Can’t
The internet may be the most comprehensive source of information ever created but it’s also the biggest distraction. Set out ...
Peggy Alexopoulou
Thu, 5 Jan 17
Every Picture Tells A Story, But Visualisation Can Tell The Right One
They say a picture is worth a thousand words.
Quang Vinh Nguyen
Thu, 4 May 17
Enough’s Enough: Buying More Stuff Isn’t Always the Answer to Happiness
The average German household contains 10,000 items. That’s according to a study cited by Frank Trentmann in his sweeping history ...
Anthony James
Thu, 5 Jan 17
How Robots Can Help Us Embrace a More Human View of Disability
When dealing with the otherness of disability, the Victorians in their shame built huge out-of-sight asylums, and their legacy of ...
Thusha Rajendran
Tue, 9 May 17
Young Workers Expect Their Older Colleagues to Get Out of The Way
There are many names for the narratives pitting the older generation against the younger: Gen-Y versus Baby Boomers, “Generation Me” ...
Michael North
Wed, 15 Mar 17
An Epoch Times Survey
An Epoch Times Survey
At Epoch Times, We Care :o)
BUCHERER
Read about Forced Organ Harvesting
Sports Elements