Mapping Mars: Science, Imagination and the Birth of a World. Oliver Morton

       Introduction

      There’s a world on my wall.

      Mountains, canyons, plains and valleys, all a faded pinkish ochre, an even tone as plain as a colour can be without being grey. The sun is to the west – shadows fall gently to the right. There are faults and rifts, ash flows and lava fields. There are creases and stretch marks, straight lines and strange curves. There are circles and circles and circles.

      No cities. No seas. No forests and no battlegrounds. No prairies. No nations. No histories and no legends. No memories. Just features, features and names. Argyre and Hellas and Isidis. Olympus and Alba and Pavonis. Schiaparelli and Antoniadi, Kasei and Nirgal. Beautiful double-rimmed Lowell. Names from one world projected on to maps of another. Maps of Mars.

      The maps on my wall, painstakingly painted about fifteen years ago, show the surface of Mars from pole to pole. They show volcanoes that dwarf their earthly cousins in age and size. They show the round scars of uncountable asteroid impacts, many far more violent than the one which killed off the earth’s dinosaurs. They show a canyon so long and deep it’s as if the planet’s tight skin has swollen and split. They show featureless plains and pock-marked ones, jumbled hummocky hills and strange creases that swarm together for thousands of kilometres, like the grain in a piece of timber. They show features perfectly earthlike and features so strange the earth has no names for them. There’s a world’s worth of scientific puzzles here, some of them already tentatively answered, most still mysterious. There’s a world’s worth of possibilities. But there’s no clear place to start the story.

      If people had moved across the pinkish ochre – if they had grown vines on the terraces of Olympus, or herded goats through the Labyrinths of the Night; if legends haunted Tempe and the dales of Arcadia, or if in Ares Vallis ancient grudge had broken into new mutiny – then it would be easy. But there are none of those tales to tell. No gardens of Eden, no sacred springs, nowhere to start the story of a world.

      Even stripped of people, with their cities and their borders and their histories, a map of earth would not be this unyielding. Global truths and discrete units of geography would draw the eye. River catchments would tile the plains, mountain ranges would stand like the backbones of continents. There would be seas and islands, well defined. But Mars is not like that. It is continuous, seamless and sealess. Its great mountains stand alone; there are no sweeping ranges, no Rockies or Alps or Andes. The rivers are long gone. There are no continents and there are no oceans, and thus there are no shores. Given patience, provisions and a pressure suit you could walk from any point on the planet to any other. No edges guide the eye or frame the scene. Nowhere says: Start Here.

      We might begin the story at one of the places that humanity has touched. In 1971 a Russian spacecraft crashed into Hellas, a vast basin in the southern hemisphere, while another landed more decorously on the other side of the planet, somewhere in or around the crater Ptolemaus. Two years later another Russian probe struck the surface somewhere near the dry valley called Samara. None sent back anything by way of a message. In 1976 America’s more sophisticated Viking landers lowered themselves gently to sites in the northern plains of Chryse and utopia, sending back panoramas of rock and rubble beneath pink-looking skies. But the Vikings eventually fell silent too, leaving Mars alone again. Preludes, not beginnings.

      Twenty years later, NASA’s little Pathfinder, cocooned in airbags, bounced to a halt in the rocky fields where Ares Vallis had once spewed out its flood waters. It let loose Sojourner, the first of humanity’s creations to travel on its own across the sands of Mars. That was a new beginning, the beginning of a grand age for earth’s robots. At the time of writing there have been automatic envoys sending data back from Mars ever since. But Pathfinder’s story cannot encompass the whole vast world in front of me. Not yet.

      What about beginning on earth? Some places here are very like locations there, perhaps close enough to be tied together by some sort of sympathetic story-magic. Maybe Antarctica, where the driest, coldest landscapes on earth are regularly visited by scientists wanting to get some sense of a smaller, drier, colder world. Or Iceland, where permafrost and lava fight as once they did on Mars. Or the scablands of Washington state, ripped clean by floods like those that scoured Pathfinder’s landing site. Or Hawaii’s volcanoes, near perfect miniatures of the Martian giants. Or Arizona’s Meteor Crater, where earthly geologists first came to grips with what a little bit of asteroid can do to the face of a planet, given enough speed. They are all places where one can learn about Mars, where the trained imagination can almost touch it. But none evokes the whole world.

      We could cast our imaginations wider, to those who have tried to speak for all of Mars. To the astronomers looking at it with their telescopes, measuring all the qualities of light reflected from its surface, seeing seasons and imagining civilisations. Or to the writers inspired by those astronomical visions: H. G. Wells and Stanley Weinbaum, Arthur C. Clarke and Robert Heinlein, Ray Bradbury and Alexander Bogdanov and Edgar Rice Burroughs. Their imaginations took a point of light and turned it into a world of experience. But their Mars was never this one, the one which we only saw – which we could only ever see – after our envoys left the earth and went there.

      Only after our spacecraft reached its orbit could we see Mars for what it is, a planet with a surface area as great as that of the earth’s continents, all of it as measurable, as real as the stones in the pavement outside your door. After millennia of talking about worlds beyond our own, of heavens and hells and the Isles of the Hesperides, humanity now has such a world fixed in its sights, solid and sure. For the moment it is a world of science, untouchable but inspectable and oddly accessible, if only through the most complex of tools. But unlike the other worlds that scientists create with their imaginations and instruments – the worlds of molecular dynamics and of inflationary cosmology and all the rest of them – this one is on the edge of being a world in the oldest, truest, sense. A world of places and views, a world that would graze your knees if you fell on it, a world with winds and sunsets and the palest of moonlight. Almost a world like ours, except for the emptiness.

      This book is about how ideas from our full and complex planet are projected on to the rocks of that simpler, empty one. The ideas discussed are mostly scientific, because it is the scientists who have thought hardest and best about the realities of Mars. It is the scientists who have fathomed the ages of its rocks, measured its resemblance to the earth, searched for its missing waters and – always – wondered about the life it might be home to. The stories they tell about the planet must have pride of place. But there are artists in here too, and writers, and poets, and people whose dreams take no such articulated form, but still focus themselves on the same rocks in the sky. They illuminate Mars; Mars illuminates them.

      It’s common to imagine that the human story on Mars will only start when humans actually get there, when they stand beneath its dusty sky and look around them at its oddly close horizon. I don’t know who those people will be, or when they will get there, or where on the planet they will first set their feet. But I know that for all their importance, they will not be a new story’s beginning, rather a new chapter. Their expectations and hopes are already being created on the earth today, by the people in this book; the process of making Mars into a human world has already begun. And I know that their landing site is somewhere on the map in front of me, already charted, if not yet chosen.

      Back to the maps, then; in particular to the 1:15,000,000 shaded-relief map of the surface published by the United States Geological Survey, its three sheets fixed to my office wall. It represents the planet