So you thought you might take a drive on Mars. See the sights, explore the scenery, maybe do a little rock-hounding. Seemed like a nice place to visit from the travel brochures, but now that you're here you're struck with the impression that this place is -- well, just plain alien. After all, where are the best places to eat? Where are any places to eat? You need a travel guide, a back-pocket reference to get you around this truly lonely planet.
Whenever I visit Mars, I depend on A Traveler's Guide to Mars (Workman Publishing, 2003). In this handy, pocket-sized volume, author William K. Hartmann tells you all you need to know to plan a visit to the red planet. Hartmann is one of those rare representatives of the human race -- a scientist who can explain his science. Not only can he write, he can paint. He beautifully illustrates his planetary tour books (he has several volumes in print) with imagined but realistic scenes he has drafted on canvas. Through his painted windows, you get to look out onto a Mars that real astronauts or adventuresome robots might not see for years to come. Here are the canyon walls and desert mesas of the current Mars, and painted scenes of the postulated ancient Mars, when volcanoes erupted and water flowed.
If I were to recommend one Martian field guide, Hartmann's would be it. As a geologist involved with some of the current NASA Mars missions, he is at the front lines of the research. He takes you by the hand and tours you around his favourite places on the planet, explaining in clear language the alien geology that created the Martian landscapes. These are landscapes at once familiar yet weird. We see things up there that look enough like Earth to make us think that long ago Mars was a smaller version of Earth. Yet we also see places strange enough to shake us back to the reality that Mars is an alien planet, likely with a different past than Earth's, with forces at work then and now unlike those Earth endured.
Hartmann tours you through all those sites, familiar and strange, places with mythical names like Hesperia, Utopia (yes, it exists, but on Mars!), Amazonis and even the infamous Cydonia, where the sensational press sees faces looking up at us. Hartmann tells us the real story about "the face," as one of several sidebars he labels as his "Martian chronicles." In these, he recounts his personal impressions of the media's coverage of Mars ("It would be terrific," he says, "if science reporters asked less about opinions and more about evidence") and his behind-the-scenes experiences with the Mars probes.
While A Traveler's Guide is well illustrated, the National Geographic Society does it one better, as only it can, in the 1998 book Mars: Uncovering the Secrets of the Red Planet. Here is Mars on a coffee table. If you want to see the red planet on a first-class ticket, join authors Paul Raeburn and Matt Golombek (the latter a principal scientist with NASA's 1997 Mars Pathfinder mission) as they embark on a lavish tour. The big format works. Mars may be a small world, but it is home to epic landscapes and sweeping scenes. Through included 3D glasses and fold-out panoramas, you get to scan the surface of Mars in three dimensions, just as we are now doing with new imagery from the current Spirit Mars rover.
Of course, you won't find today's images from Mars in this or any book yet, but that's the price of adventure. Anything in print today is immediately outdated by the explorations of the latest Mars probes. And that's just how scientists want it. Nevertheless, books like the National Geographic volume give us Earth-bound Mars explorers the valuable context to understand what beams back daily from the cameras of the landers and orbiters on Mars.
While these two volumes are my personal favourites for providing the science background, Mars is a planet also rich in human history. You cannot appreciate Mars without knowing why it draws us toward it. That's the question William Sheehan and Stephen James O'Meara tackle in Mars: The Lure of the Red Planet (2001, Prometheus Books). The authors have long made it their quest to scour the history of astronomy, seeking stories of mistaken identity, things imagined through the eyepiece that later proved to be chimeras. And heaven knows, Mars is home to all manner of imaginary sightings, not the least of which are the canals seen and mapped in detail a century ago by Percival Lowell. Sheehan and O'Meara, two accomplished observers themselves, recount the human stories behind the canals, seas, mountains and fields of green vegetation once seen with confidence by 19th- and early 20th-century astronomers peering through the eyepieces of their great telescopes.
Why were they so wrong? In answering that, the authors explore the Mars we knew before the space probes arrived. While the canals and fields of green have long since been disproved, even before the space age, the Mars that Sheehan and O'Meara uncover is still the Mars that lures us on. While we don't expect to see canals any more, we have just landed a robot on Mars to search for signs of water. The ill-fated Beagle 2 lander was to have scratched the surface seeking signs of life. We are still seeking a Mars that looks, or looked, like Earth. The lessons we take away from Sheehan and O'Meara's historic Mars is that the planet always fools us. The real Mars is never what we hope it to be. It is an alien planet with mysteries and marvels awaiting us over the next hill.
Alan Dyer, an astronomer and science writer in Calgary, is co-author of The Backyard Astronomer's Guide.