'We are not alone' book review and Martian thoughts

This week, I've been reading 'We are not alone' by Dirk Schulze-Makuch and David Darling, a popular science book that reports on and explains the evidence for life in other parts of our solar system and what form that life might take.

The book's first half focusses on Mars and the evidence for life on that planet. That particular topic has been in the news this week. There's been lots of media discussion and NASA press conferences about the significance of tell-tale trails on the martian surface, particularly running down from certain cliffs and mountains. As 'We are not alone' points out, this evidence has been known for ten years or more, and so it's surprising that it's being reported as such a big deal now. The cynic in me would wonder if it's something to do with the release of Matt Damon's latest movie 'The Martian', but that's probably just a coincidence.

As Darling Schulze-Makuch's book explains, the story of evidence for life on Mars kicked off with Percival Lovell and his claims for Martian 'canals'. In truth, Lovell was simply re-iterating an Italian astronomer's observations of 'canali' on Mars, which is Italian for 'channel', but Lovell's embellishments and conclusion that Mars was inhabited by a civilisation struck a popular chord.

Later on, probably the most important episode of 'life on Mars' evidence came from the Viking lander expedition. Devices on the Viking lander found evidence of life in the Martian soil. This evidence should, at least if NASA had followed its own rules, have been enough for scientists to declare that life does exist on Mars, but certain scientists on the NASA panel had their way and the evidence was eventually dismissed as inconclusive.

'We are not alone' reports on this controversy in great depth (a controversy that was also reported in Michael Brooks' book '13 things that don't make sense', which I heartily recommend). In the Viking chapter of their book, Darling and Schulze-Makuch explain both what happened and the characters involved and what the Viking evidence could indicate in terms of Martian cell biology. They explain how the organisms that seem to have been detected by the Viking lander could be using a peroxide oxygen system to stay alive in Mars's hostile surface environment. I was greatly interested in this idea and, for me, it was the scientific highlight of the book.

'We are not alone' isn't a big book - it runs to 174 pages excluding references - and I was left wishing for more when I finished it. I'd happily buy a future edition in which the authors extend the range of their investigation to look at exoplanets and perhaps go into greater depth explaining alternative biological systems that use silicon or the peroxide system or other exotic biological processes. A hardback version with more illustrations and colour ones would also be most welcome. Overall, I give 'We are not alone' an enthusiastic thumbs-up.

While reading the book, I thought some more on the subject of Martian life and a strange idea popped into my head. As Darling and Schulze-Makuch's book explains, Mars looks to have been a habitable, water-filled world hundreds of millions of years ago. Our sun has steadily grown brighter and hotter over time and the 'Goldilocks' or habitable zone around it has shrunk inwards, towards Earth and away from Mars. This change, combined with Mars's smaller size and weaker gravity, consigned that planet to lose its atmosphere and become what is now a seemingly sterile world.

Although this story makes Mars appear like a world that's empty of life, that may be a deceptive view. In a sense, Mars was the first planet in our solar system to be a habitable place to live, before Earth became the jewel around our sun. The presence of bacteria and other living organisms have been found in meteorites that have landed on Earth. These meteorites include ones that have been identified as having come from Martian impacts and eruptions. This indicates that life can easily be seeded from Mars to Earth and vice-versa (a topic that's also covered in 'We are not alone'). It's therefore sensible to believe that some form life did evolve and develop on Mars hundreds of millions of years ago. With hundreds of millions of years of time to develop, there's every reason to think that advanced, intelligent life developed on Mars a long time ago.

The interesting question then becomes; if intelligent, advanced life did develop on Mars, what did they do when the surface of their planet became increasingly inhospitable? The process of the planet's surface decay would have been slow, but inexorable. How did an hypothetical advanced, intelligent race living on the planet's surface deal with their growing predicament? What did they do when their atmosphere leaked away and their surface became irradiated with ultraviolet rays?

There would seem to be two options available in such a situation. The race concerned could have either left Mars entirely or gone underground. If they left Mars entirely, the trail goes cold but if they went underground, such a move creates some fascinating consequences. If they went underground, they would have escaped their planet's thin atmosphere and harmful rays (I'm ignoring the 'protective surface domes' option as I think it's a hiding to nothing in the long term). If the Martians then created underground cities, they would have then been able to control their environment. They would need an energy source to build and maintain these cities but on a planet with constant geothermal heat, that wouldn't have been a problem. They could have then used technology to create light and therefore food. Water is available on Mars under the surface and at the poles and so that key resource would also have been available in large amounts. It would seem that all the requirements for a successful underground existence were present on Mars.

If the Martians did go underground, how would underground life have affected them? To work this out, we can start by assuming that the Martians had technological skills. In such a scenario, they would have faced no biological threats underground as they would have been able to control their environment totally. Evolution being what it is, they would then, over millions of years in their cave-systems, have slowly adapted to a form that was ideally suited to their underground life in a predator-free environment. They would have become relatively soft and weedy but with large brains and highly dextrous fingers. They would have lost pigmentation in their skin. Their eyes would have grown large to work in low-light conditions. They would probably have switched to echo-location, even without specialised organs, in a similar way to the cave-swifts of Borneo. Such a creature would probably look something like…

…the creature shown on the left. This 'Testors Grey Alien' model illustration has all the features described; fragile body, dextrous fingers, large eyes and no pigmentation. It is therefore logical to suggest that grey aliens, an urban-myth species so heavily discussed on the web, could actually be Martians that have been living underground on Mars for millions of years, as a natural strategy to avoid the degradation of their planet's surface millions of years ago.

But what are the ramifications for the human race if a Martians 'grey alien' race does exist, one that is entirely at home underground? This is a speculative but very interesting topic. Let's summarise the earlier paragraphs: The Martians retreated underground on Mars as their planet's surface worsened. They settled into their new home, developed appropriate technologies and optimised themselves and their abilities to make maximum use of their new environment. They evolved, became technologically highly advanced and now are a race that has the technological ability to cross space but lives underground. So far, it's a reasonable set of connections.

But there's an interesting side-effect to all of this. If Martians have been living underground for millions of years, they probably don't any longer want to be on the surface of a planet, even one that we might think is idyllic. For them, interplanetary and interstellar exploration isn't going from one planet's surface to another planet's surface, it's going from one planet's interior to another planet's interior. The surface of planets, for the Martians, is now how the deep sea is for us; exotic, interesting but only something one explores now and then in a highly protective craft.

There's more. Since intelligence and curiosity go hand in hand, the Martian troglodyte race would have almost certainly, once they were feeling sufficiently skilled and resourced, have created craft to take them from their planet's interior to the interior of neighbouring planets. They've built such craft and headed off, tackling their nearest planet first and then on to others. They've expanded, colonise and explored and have done it without the surface dwellers on other planets possibly even finding out about their activities. Those surface races would never see any Martian visitors' bases or cities. Even if they suspected that the troglodyte Martians did exist, they'd have to dig down to find their cities.

If all that is true, then a very simple but shocking consequence is highly likely, that the interior of our planet is inhabited by Martians. This sounds ridiculous but, logically, it's a reasonable conclusion to draw from what's already been described. The hardiness of some organisms, the history of Mars, evolution, biology and the capabilities of technology make it a tangible possibility. For anyone who wants to investigate whether this actually true or not, I'd recommend YouTube and the internet; there's lots of material on the subject of 'underground alien bases'. I've no idea if the stuff is true or not, but it may make for interesting reading/viewing. Whatever happens, it's a fun idea. The Truth is down there…