Mars: the story so far
Image credit: Nasa
Planetary geologist, geophysicist and leading science-fiction author Simon Morden takes us on an objective tour of Mars based on the science and the facts.
“I don’t gloss over the controversies and don’t pretend that we know more than we do about Mars,” says Simon Morden. “But we know enough to tell a story about how Mars started and how it may well end.”
In between these bookends of geological time, he says, “the most intriguing thing is that the planet we all thought we knew as a dead, cold, dry place is only like that sometimes”. By which he means that because of Mars’s orbital eccentricities, today “we could simply be looking at Mars while it is asleep. And the chances that it will wake up are genuinely high.”
He says the fact that we’re not recording active volcanoes or seeing vast expanses of water on the surface is a function of the era we live in and the moment at which we’re observing it.
Morden’s latest book – ‘The Red Planet: A Natural History of Mars’ –is careful to invite the reader away from the position of just looking at a passive, if somewhat conspicuous, feature of our night sky. The way he does this is to tell the whole story from the planet’s formation 4.5 billion years ago, along the narrative path that takes in the geological era of cataclysmic meteor strikes, explosive volcanoes and a vast ocean that spanned the entire upper hemisphere, to the frozen ages that saw its atmosphere steadily thinning and leaking away into space.
Today, perhaps because Mars is by comparison such a calm place, we are able to send a succession of machine-based missions to explore and analyse the environment. As we speak, Nasa’s Perseverance rover (or ‘Percy’) is on the Martian surface transmitting data back to Earth, while there is a succession of Chinese, Russian/European and Japanese landers due to arrive in 2022. All of which means it’s high time we caught up on what we know of the story so far. Which is just as well, because Morden says that if there is a ‘take home’ from his book, it is that “Mars isn’t what we thought it might be”.
The publicity material for Morden’s book claims that ‘the Red Planet’ is “as close as we can get to an eye-witness account of this incredible place”. Normally, objective journalists would tend to take such publisher hyperbole as good-natured nonsense. But considering Morden once held a piece of Mars in his hand, perhaps the claim isn’t quite so overblown as it sounds.
As a young post-doctorate academic researching the magnetic properties of meteorites, he sent for a sample of extraterrestrial material from Nasa’s collection that he could literally put under the microscope. The sample turned out to be what he thought was a dud and so he sent it back.
“But I should have looked harder, questioned more,” he says, explaining that six months later a laboratory in Japan analysed the gases trapped in the same sample and concluded that the previously miscategorised ALH84001 – a serial number that comes alarmingly readily to Morden’s recollection, even after several decades – had formed on Mars and was now “far too precious for a junior researcher to work on. I’d missed my chance. I left academic research. Eventually I became a science-fiction writer. I even wrote stories set on Mars.”
We read it for you
A distillation of the latest research into ‘all things Mars’, Simon Morden’s ‘The Red Planet’ is written from the perspective of a specialist, but with the informed layperson as the audience. Using data from the Mars probes and the most up-to-date theories on planetary geology, in the course of just over 200 pages the author condenses just about every scrap of current thinking on the subject into a highly entertaining work of popular science. Covering everything, from its origins to what’s involved in getting humans there, mountains of scientific tracts have been boiled down by the former science boffin who now tells stories for a living. While you could probably find most of the actual data for yourself, the real achievement here is how the threads of all those academic papers have been woven into the rich narrative tapestry that is ‘The Red Planet’. Great stuff.
Humans have always been fascinated by Mars and “from the very first time that people turned their telescopes towards Mars in the 17th century, with all the optical problems that went with it, trying to stare outside a soupy and turbulent atmosphere, we’ve been able to pick out the bare features”. One such feature was the now infamous ‘canali’, a word mistranslated from the Italian as ‘canals’ rather than (the correct) ‘channels’, leading everyone by extension to believe that they were created by intelligent life: “and that obviously caught the very popular imagination.”
The idea that there was life on Mars, “never really went away until the 1970s when we were able to park Mariner in orbit. The photographs we got back were utterly revolutionary. I don’t think that we could really say we knew anything about Mars – apart from its gross features – before we got the Mariner pictures back. Also, Mariner arrived there during a colossal dust storm and so Mars just looked like a giant pink snooker ball. As the storm subsided, we started to see the tops of volcanoes.”
Morden thinks that in terms of exploration of the Red Planet, we are good at “throwing more and more instruments at Mars. But the information that comes back doesn’t always answer our questions. We’re drowning in data but we’re lacking in explanation.” We can describe Mars in terms of its “height, breadth and depth” he says, but when it comes to assembling the narrative of how everything is ordered “it’s still quite ambiguous. We have lots of theories, but we don’t have that settled, concrete evidence that we would hope for. If you take Martian vulcanism as an example: we know that the volcanoes are incredibly long-lived. There’s no plate tectonics and the hotspots don’t move, which is why they’re tens of kilometres tall. But what we can’t tell is how recently they erupted. And we can’t tell that because the more recent lava flows simply resemble those from one million, ten million, a hundred million years ago. So far as we can tell vulcanism has stopped, but that’s a problematic judgement call.” The reason we can’t be sure is “we don’t have the samples, so we don’t know”.
The idea of differentiating between what is known and what is conjecture is a feature of ‘The Red Planet’ and one that gives it an emphatic tone of authority. But since Morden is much better known as a writer of science-fiction novels with imaginative conjecture at their creative core, I’m bound to enquire if there is a conflict of interest at work.
“Yes,” he replies. “I wanted the best for Mars. I wanted to tell a story that wasn’t a dry, academic book. I wanted people to be as enthusiastic about Mars as I am, and it is undeniable that there are parts in the conjectural story of Mars that I want to be true. But my book is as objective as I could make it.”
‘The Red Planet: A Natural History of Mars’ by Simon Morden is from Elliott & Thompson, £14.99
Mapping Mars
Making maps of Mars has a long and somewhat ignoble history. Accurate maps – ones that might help us navigate its surface – have only been around for the fifty years since the Mariner 9 space probe took the first detailed pictures from orbit in 1972. Before that, much of what was drawn was not just inaccurate but fanciful and frankly wrong. Credit where it’s due for the attempts made by Johann Mädler in 1840, Richard Proctor in 1876 and Giovanni Schiaparelli in 1893; they used serious scientific observations to create their maps, but their technology – ground-based optical telescopes – was simply too limited to pick out anything but Mars’s brightest and darkest features.
After Mariner 9 had taken photographs covering most of Mars, the process of making the first proper map could begin. The mapmakers divided Mars up into thirty quadrants: eight rectangles above and eight below the equator, six circling the north pole, six around the south pole and the two polar regions themselves. Any attempt to represent a spherical object on a flat sheet of paper is going to distort it, so the polar quadrants aren’t rectangles but are instead circular, and each quadrant varies in the size of the area it maps, from nearly seven square kilometres at the north and south poles, to 4.5 million for the equatorial quadrants. Each of these quadrants needed a name other than the prosaic nomenclature of MC-1 (short for Mars Chart) to MC-30. These thirty names became wedded to the areas they describe, and they roll off the tongue like a shipping forecast for another planet. As the maps became more detailed with each successive mission, they became populated with new names and the International Astronomical Union became the final arbiter of nomenclature.
Edited extract from ‘The Red Planet: A Natural History of Mars’ by Simon Morden, reproduced with permission.
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