After a few sols, Phoenix extended its robotic arm and began to take pictures beneath the lander. There were bright patches, cleared smooth by the exhaust of the retro rockets. And something shining in the sun, an absolutely pure white. Ice? Or perhaps salt? And there was something else that was odd in the images: bumps on the lander legs, bulbous half spheres of some substance that over the course of a few sols seemed to have merged like raindrops on a pane of glass. A team member from the University of Michigan suggested that these were, in fact, water droplets. “Obviously they came from somewhere—they weren’t there when we launched,” Smith told the press, puzzled. But the temperature had never reached anywhere near warm enough for water to be in a liquid form. It had never even topped minus 25 degrees Celsius.
When the robotic arm began to dig, it hit another white patch, and the rotating rasp at the end of its scoop started throwing out little chunks of bright material. Four sols later, the material had vanished. It had completely vaporized. “It must be ice,” declared Smith, for salt wouldn’t just disappear. In the next trench, the arm hit a hard patch and simply couldn’t dig any further. That patch, also gleaming white, was at the same depth. It was part of a layer. The scientists determined that it was indeed the ice they had come looking for, a pure reservoir, less than thirty centimeters beneath the lander legs.
Next came the analyses, the only time water had ever been directly investigated on Mars. The two main instruments, rising in metallic boxes from the deck of the lander, were called TEGA and MECA. Inside TEGA were eight tiny furnaces, which were designed to blaze forth in the polar cold, revealing the chemical nature of the constituents. When the furnace temperature reached its maximum—far hotter than that of the Viking ovens—the vapors driven out by the baking were “sniffed” by the mass spectrometer for tiny quantities of organic molecules. Delivering the samples proved harder than expected, but when the measurements were finally made, TEGA discovered calcium carbonate, the same stuff in Tums. The kind of mineral that was indicative of a watery past.
Phoenix’s other key instrument, MECA, had a Wet Chemistry Lab—or WCL, pronounced “wickle.” The WCL was designed to dump sugar-cube-sized plugs of soil into a soaking solution, then simmer and stir them. Tiny sensors along the wall of the beaker were fashioned to measure things like salts and acidity. MECA found that the polar terrain was, if anything, slightly alkaline, the kind of soil you’d grow asparagus in. The fact that alkaline soils had been discovered on Mars suggested that the planet might not have been entirely bathed in acid.
The WCL was also designed to assess a range of chemical constituents, including nitrate, one of the most essential for life. A few years before Phoenix landed, the presence of nitrate salts, found in extremely dry desert soils here on Earth, had been hypothesized to exist on Mars. Thirty sols into the mission, however, when the WCL did its first experiment, the sensor designed to detect nitrate went absolutely bananas. As it turned out, the detector was also sensitive to another molecule, one that was far rarer. While a small response could have signaled a large concentration of nitrate, a whopping signal could only mean one thing: a massive amount of an obscure salt called perchlorate.
It wasn’t a common word in the English language. Smith had to go and look it up. Traces of perchlorate were present on Earth in extremely arid places like the Atacama Desert, measured in grams per hectare. But at the Phoenix landing site, just a few handfuls of soil yielded the same amount. Viking had detected chlorinated molecules, but the Viking science team had assumed they were the residues of cleaning fluids used to disinfect the lander deck. It was now clear that those combusted chlorinated organics were the exact fingerprints that would have been left behind if perchlorate was heated in the presence of organic molecules. The oxygen released would have burned the organic molecules up. The realization had startling implications: Perhaps the Viking experiments hadn’t been compromised.
I wondered what Wolf Vishniac would have made of it. And Carl Sagan and Vance Oyama, who had both lived through the crushingly disappointing results of Viking but had not lived long enough for this. The lack of any simple organics on Mars had been so hard to understand, as organic molecules also have nonbiological origins. At least some organics should have rained down from comets and meteorites. But as the Mars community now realized, perchlorate could have been sitting right alongside them, happily coexisting for billions of years, until they were heated in the Viking oven. The perchlorate would have destroyed any trace of organic material, just as it did in the polar soils analyzed by Phoenix. We hadn’t known it, but we’d been dry-cleaning the samples.
Smith and his team continued to scour the literature. They discovered that perchlorates, as reactive chemicals, might be toxic to future astronauts, but also that perchlorates aren’t necessarily bad for microbes. They keep water thawed in a liquid form. Just like the salts we spread on icy roads, concentrated perchlorate salts can act as an antifreeze, massively depressing the freezing point of water to near minus 70 degrees Celsius. Perhaps the bumps on the lander leg were in fact water: water mixed with a bit of perchlorate. Some microbes, the team discovered, could even use perchlorate as a source of energy.
* * *
—
PHOENIX CONTINUED ITS work through the summer of 2008 and filled its feed with updates. On a day when not much happened: “Feels like scratching nails on a blackboard here.” On another: “Just finished hunkering down for a big dust storm.” As Phoenix wound down, the tweets turned reflective: “I’m not mobile…so here I’ll stay. My mission will draw to an end soon, and I can’t imagine a greater place to be than here.” “Whoa, so much sadness about the heater turning off.”
Before Phoenix died, the instruments recorded falling flurries: water-ice crystals floating gently from high, thin clouds. They were wispy things, like cirrus clouds here on Earth, releasing a sprinkling of tiny particles, a kind of diamond dust. No one ever knew it snowed on Mars, and now it’s forever known—a final gift from the spacecraft, a small piece of the permanence of the universe that we don’t share in. Most of it vaporized, but a few times, like on sol 109, the streaks touched the ground. There wasn’t much of it: “If you melted it all in a pan, [you] would be barely wetting the surface,” Smith said. But if you were there on Mars, looking up from Vastitas Borealis, it would have been enough to make the sky sparkle.
Unlike other Mars missions, Phoenix was always marching irrevocably toward its end. The light was waning, the temperatures were plummeting. Phoenix kept taking measurements and sending lonely updates. But by November of 2008, the weak sunlight could no longer charge the solar panels, forcing the instruments to shut down. Phoenix slipped into “Lazarus mode,” operating autonomous programs on board but no longer accepting new commands. It was a bittersweet moment. The engineers detected some feeble signals for a few more days, then Phoenix succumbed to the polar darkness. The spacecraft’s final tweet was: “01010100 01110010 01101001 01110101 01101101 01110000 01101000.” Binary for “triumph,” followed by a heart emoticon. Within a few months, the air itself froze, entombing Phoenix in dry ice.
* * *
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THERE HAD NEVER been any real hope of Phoenix surviving the winter, but the following spring, the Mars Odyssey orbiter nevertheless flew over Vastitas Borealis, listening for a beep. No signals were ever heard, even as the lander entered into round-the-clock sunshine that summer. There had only been one part of the mission designed to persist, and it was affixed to the deck of the lander.
It was a mini-DVD containing literature, art, and messages from planetary scientists. Velcro’d to the deck of the lander, the disk was stamped with a paper label, the kind I used to print on a dot matrix when I burned a CD mix for a friend. The collection had originally been assembled for the surface station component of a Russian Mars mission in 1996, but that mission failed, streaking across the sky like a fireball before falling back to the Earth. The idea had come
from Louis Friedman, the executive director of the Planetary Society. The top of the disk read, “Messages from Earth. Attention Astronauts: Take this with You.” On the left, there was some clip art showing a set of old books, and then at the bottom, text that read, “First Library on Mars.”
Included were more than eighty books and stories, poignantly evoking the fact that an entire exploration of Mars had been imagined before anyone left the planet. They chronicled concepts for rocket ships and spacesuits and an astonishing array of other technical details, like solar-powered flight. There were tales about hypothesized contact, telepathy, and utopian existence, and at the same time there were aliens and invasions and bloody wars. Some of it was classic pulp: sword-wielding heroes defending helpless, barely clad women, the kind of science fiction I always found dispiriting, but there were also works from philosophers I loved, like Bertrand Russell.
There was a recording of Carl Sagan, speaking to future Martians from a waterfall near his home in Ithaca. There was Arthur C. Clarke, speaking from Sri Lanka, with a wild cacophony of birds in the background. There were surrealist paintings, comic strips, film posters, and ads featuring Mars in magazines. There were illustrations from novels, maps drawn by Lowell, photographs from orbit, and a plaque from the bridge of the Starship Enterprise. There were live recordings of mission control during the Viking landings. There was the 1940 recording of H. G. Wells meeting Orson Welles, talking about War of the Worlds, the book and the broadcast.
The most recently recorded words were Peter Smith’s. In his introduction, he talked about the incredible progress of science—modern medicines, the decoding of the human genome—and he talked about his fears for our planet, his worry that the future might not see peaceful advances in culture, technology, and science. He wondered if our species would survive. He talked about the technology of the future, likely as unrecognizable to us as a laptop computer to Attila the Hun. How peculiar to send a mini-DVD, he mused, which “would not be current even twenty years” into the future. What brave soul might find it? A future astronaut? Might that thin slip of archival silica glass—protected from Earth’s rapid decay, preserved on Mars for hundreds of years to come—outlast our entire civilization?
If anything persisted that long, how fitting that it would be our words—our thoughts. One of the oldest pieces included in the collection, and one of my favorites, was Voltaire’s “Micromégas.” In the short story, written in 1752, a 120,000-foot-tall visitor from another world comes to Earth and initially believes our planet must be devoid of life. But he keeps looking, and when he eventually sees a moving speck in the Baltic Sea, he picks it up with his little finger and puts it on his thumbnail. He discovers it’s a whale. He eventually spots another speck, similar in size, and with his magnifying glass, he realizes it’s a boat filled with Arctic explorers: “…after having commiserated [with] them for being so small, he asked if they had always been in that pitiful condition little better than annihilation, what they found to do on a globe that appeared to belong to whales, if they were happy, if they increased and multiplied, whether they had souls, and a hundred other questions.”
I often think about that story, about how much life was teeming beneath the 120,000-foot-tall visitor, about how tenacious he had to be to recognize it. It reminds me of Carl Sagan as he peered at those satellite images, trying to spot roads and fields, using his own magnifying glass of sorts. Do we also have the scale of life completely wrong? In terms of proportion, humans only interact over a few orders of magnitude: micrometers, millimeters, meters, kilometers. How much bigger, or smaller, might life be? And what of time? In Copenhagen, I held cells in my hands that were twenty thousand times my age. Cells that were older than the pyramids, older than writing, older than language. Cells that were alive before the dawn of my species, as the ancestors of Homo sapiens trudged the Earth. Cells that persisted as humans walked from Asia to America, as the sea slowly closed. That survived, indifferent, beneath the “Road of Bones,” as in the blink of an eye a million people died in Soviet labor camps above. Cells that could remain cocooned until there are no more children, there is no more highway, and there are no more bones.
Then again, what is even half a million years in the life of a planet? Would the giant ever have found life in the Kolyma lowlands? Would he have been an instant too early, or an instant too late? Would he have accidentally stamped out what he was looking for? What kind of magnifying glass would have seen ancient cells slumbering so deep in the permafrost, barely respiring, so easily extinguished?
Like the giant, I’d spent a lot of time trying to peer into worlds too small to see. Once, in one of my teaching labs at Oxford, I’d spent hours observing a tiny fruit-fly larva. Students of developmental biology and genetics, almost without exception, study Drosophila as a model organism—the hovering black dots of the adults as well as the eggs, larva, and pupa. The organisms grow quickly, and by playing with their genes, scientists can manipulate them rather mercilessly, causing them to grow eyes on their legs or extra sets of wings and learning a great deal in the process.
In that particular lab, I’d been told to familiarize myself with the larva’s functioning under a dissecting scope, then to mount its brain on a glass slide, to study normal cell division, along with its testes, to study germ cell division into gametes. But even after my professor’s prompt to begin the dissection, I dallied. I pushed bits of sugar in the larva’s confused path and watched as it attempted to climb my tweezers. I couldn’t help contemplating the set of circumstances that led this tiny creature to my scalpel. It felt wrong to kill it, but how many lives had I taken inadvertently, without even thinking? There had been countless little genocides that morning alone, just as I walked through the meadow to class. What universes were down there? What noises were too small to hear beneath those blades of grass, where long-horned beetles stampeded like elephants?
I lifted the larva into the pocket of my lab coat and excused myself. I held the slide steady while I walked, glancing down into my pocket every few seconds as I descended to the stairs and found my way to the cafeteria. I left it on a bite of the banana I’d brought for lunch, spat out and dribbled from a napkin, in the base of a rubber plant in the zoology building. I returned to the classroom and gazed for nearly an hour at a blank slide under the microscope, a vast field of emptiness.
* * *
—
WHAT MIGHT I be missing? I contemplated this question in terms of tiny microbes, and the world beyond my doorstep, and the planets I could barely see. Occasionally, my thoughts returned to a little Dutch book from the 1950s—Cosmic View, the Universe in 40 Jumps—in which the illustrations expand and contract, traveling outward by orders of magnitude to the edge of the universe, then inward to an atom in the hand of a girl sitting in a chair in the courtyard of her school. There were times, somewhere between the distant galaxies and the atomic microcosms, when I would pause long enough to realize that, like the girl, I was sitting alone.
Then a friend of mine tried to set me up on a date with one of her law school classmates. I initially declined. I was content with my books and my science. I’d never been on a blind date, and I couldn’t imagine it being a good idea. “But he knows you,” she insisted. So one evening I finally agreed, and a week or so later the guy with the “HELLO” name tag, the philosopher turned lawyer, showed up on the steps to my apartment. He smiled as I cracked the front door and peeked out.
I marveled at his easy confidence. He effortlessly maneuvered his stick shift out of a tight space on the steep hill of my street, then we drove with the windows down to East Cambridge. He’d made a reservation at a restaurant named after Afghanistan’s second-longest river, where we shared aushak and showla and a plate of kaddo, baked baby pumpkin seasoned with sugar. At one point, he made me laugh so hard that yogurt nearly flew from my mouth.
How could it last? He was moving to Texas at the end of the summer to clerk with a pr
ominent judge there, to glimpse the front lines of the civil rights issues he’d worked so hard on as a student. I was staying in Massachusetts.
But in the weeks that followed, it was as if a warm candle began to glow. We drove up into the dairylands of Vermont to buy cheese and penny candy. We took the ferry to the Harbor Islands and hiked the green cliffs. I started leaving the lab in the early evenings to go find him wherever he was, which was often playing guitar on a porch somewhere with his law school friends. We’d wander the streets until we happened upon an old bookshop, or bike down to the river to watch the sun set over the tea-colored water.
He was supposed to be studying for the bar exam, but as spring turned to summer, it seemed he was spending all his time with me. My own worry swept into the void created by his calm. I decided I’d better make myself scarce for the final weeks before his test. When a friend invited me on a trek from Norway to Finland, over the top of Sweden, that seemed sufficiently far. In a book she gave me, I read about Arctic creatures and ice, and about how Arctic explorers were always running into one another, despite the oceanic vastness of the landscape. They would wander through uninhabited territory, alone and prepared to remain so for their entire trek. Yet their paths would invariably cross. I was compelled by the idea, how these chance encounters were simultaneously so improbable and so inevitable. It seemed like humanity in a nutshell: that in the moment of our greatest isolation we would be drawn to the same breaks in a landscape, the same dramatic bit of a cliff, and find each other. For ages, I’d wanted to explore that landscape for myself, so I emptied my savings account—the meager remains of my grad school stipend—bought a ticket, and flew to Tromsø. After gathering supplies, I climbed the steps onto a bus east to the place the journey would begin.
The Sirens of Mars Page 17
