Antarctica

by Gabrielle Walker

  Now that we were in a hollow and the wind had dropped, the sun was baking. My parka began to seem ridiculous, even though the air temperature was technically far below freezing. I felt sleepy, and had a sudden urge to lie down and bask on one of the rocky surfaces. I knew what the cyanobacteria saw in this place. It wasn’t even that hard to live here. Thanks to the weird combination of geometry and height, life really was a beach.

  And yet, Chris had found his rock dwellers throughout the Dry Valleys. And similar rocks may also have provided one of the final refuges for life on Mars.

  Just beyond Battleship Promontory lies another part of Antarctica’s living Martian metaphor: a place where space itself comes to Earth. This is an area known as the Allan Hills for the few isolated mountains that poke their necks up through the ice. Apart from these, the surface up here on the edge of the vast East Antarctic Ice Sheet is mainly featureless. A helicopter pilot told me that in his first season he was detailed to take some researchers up into the Allan Hills and asked for a map. His boss took a blank sheet of paper, put a pencil dot in the middle and handed it to him.

  But remote or not, this is one of the best places on Earth to find rocks from space. An astonishing amount of extra-terrestrial debris falls on the Earth every year. Some is in the form of dust that blazes brightly through the sky as a shooting star but burns itself up in the process. Once in a while there is also a really massive space rock, an asteroid, which collides with the Earth with devastating consequences. That’s what did for the dinosaurs, and we humans could meet the same fate if we encountered a similarly unlucky strike. The really big hits like these carry so much energy that there’s little or nothing left of them afterwards, just a mighty crater and a planet of dazed or dying creatures. In between these two extremes are moderately sized rocks, large enough that something survives the burning through the atmosphere, and small enough that they land relatively gently, and remain on the surface as an alien rock. It is these remnant rocks that we call meteorites.

  Almost all meteorites come originally from the asteroid belt, a ring of potato-shaped rocks that marks a failed planet, between Mars and Jupiter. Jupiter formed so quickly and became so large that its gravity disturbed all the building blocks in its vicinity, and prevented them from forming a planet of their own. The asteroid belt is builders’ rubble, left over from the creation of the Solar System. Rocks from there tell us about the birth of our planets, our Sun, and even about what came before.

  But that’s not the whole story. A very few, very rare meteorites come from more exotic locations. Antarctica has gathered more than its fair share of these precious alien visitors, along with their extraordinary insights about us, and our place in the world.

  Ralph Harvey, a long-time meteorite hunter from Case Western Reserve University in Cleveland, Ohio, runs a programme called ANSMET (which stand for the Antarctic Search for Meteorites).3 The programme is a strange beast, unique among all the science that takes place on the continent. It’s funded by a combination of NASA, the NSF and the Smithsonian, and the field party always consists of volunteers. Though they are usually experts in meteorites, they themselves have nothing to gain. Anything they find must be bagged, logged and handed over to the authorities. They can then put in a proposal to study any of the meteorites they find, but will be treated like any other researcher: no special privileges, no queue jumping. And certainly no private collecting of samples.

  Ralph tells his volunteers this every year before they even make it out on to the ice: ‘It embarrasses me to say this, but there are no meteorite souvenirs for you guys. Don’t look for personal satisfaction in terms of the rocks you’ve found or the rocks on your shelf. What I want you to take home is the ability to tell great tales. If you want a souvenir, buy a T-shirt.’ He calls the programme ‘extreme altruism.’

  And yet every year he gets hundreds of applicants. Ralph handpicks the teams himself and, though he considers every application that he receives in writing (test number one: can you write a letter, using a pen, on a piece of paper?), it’s probably not worth bothering unless you also know someone who can recommend you. Character matters more than anything in this particular game, and Ralph requires personal or good secondhand knowledge of everyone he chooses.

  He’s not interested in adventurous types. It’s more important to have the ability to be still, to read books calmly in a tent for days while the wind is up, to be respectful and give other people their space. Machismo is also out. When you’re feeling miserable you need to say so. ‘If you’re cold, tired, hungry or thirsty enough that you’re skipping over meteorites, the whole system breaks down,’ he said. ‘I’d rather call the day short than miss something and if one person is feeling ineffective there will be others at least on the verge. Everyone has times that they feel weak, and we all have to agree to admit this and accept it.’

  Still, being on an ANSMET team is not for the faint-hearted. If you’re selected you’ll find yourself on some windy part of the plateau for weeks on end, out on a skidoo from early morning on every possible working day. Days off come when the weather says so, not when you’re tired, or fed up, or it’s the ‘weekend’.

  The worst days are the ones where the wind is just low enough that you can work, but still high enough to hurt. It pokes its fingers into any tiny gap it can find, between your gloves and your parka, or where your neck gaiter has slipped slightly. Your goggles fog up constantly. Your big red hood is up, your vision restricted to one small oval framed in fur. You’re wearing 14 kg of clothing, manhandling a hefty snow machine, struggling with the pain of ‘skidoo thumb’ from constantly holding down the throttle. You’re bumping over sastrugi—ridges of wind-hardened snow—and if you hit one the wrong way you can find yourself unceremoniously dumped off the back of the skidoo. The automatic cut-off will trigger so you don’t then have to chase the machine, cartoon-fashion, but it’s still mortifying if anyone sees.

  And, of course, it’s always windier and nastier when you’re not finding meteorites. But then, when you do find one, the wind feels a little lighter and the air warmer and the sun brighter. ‘Each one you find, there’s a switch in your brain that says “that’s a rock from space”,’ Ralph told me. ‘If someone new finds it, it’s like giving a child a present, but everyone has a first meteorite every day. It’s like mini birthday parties all day long.’

  Searches are highly systematic. You go out in a posse of five or six skidoos, sweeping back and forth like Olympic lane swimmers, perhaps one hundred feet apart. You always start into the wind. It might sound masochistic, but the first pass is usually just reconnaissance and this way you have the wind at your back for the return, when you’re looking more carefully. You’ll probably have to wear your full-face mask and heavy gloves for the upwind part, and downgrade to goggles and light gloves for going downwind. But no one ever does passes with a crosswind—or whichever way you were heading you’d be miserable.

  If you see a meteorite, your heart might skip, even if it’s your tenth or twentieth of the day. You’ll jump off your skidoo, wave your hands, shout, do whatever it takes to get everyone’s attention. (If someone else is shouting you stop, throw an ice axe overboard to mark exactly where you’d got to, then head over to check it out.) Then you get out the Collection Kit, a black and white daypack. In the front pocket is a plastic bag of aluminium strips bearing numbers, and a chunky metal counter, a hand-me-down from the Apollo missions. You pull out a metal strip at random—the number will be the meteorite’s name until it can be properly curated. You punch that same number into the counter, hold it just above the rock and take a photo.

  The next step is to collect the specimen. From the main pocket, you take a sterile plastic bag. You might use a pair of sterile tongs to pick the meteorite up. More likely you’ll scoop it into the bag without touching it, brushing it with your parka or letting your nose drip on to it. You should always make an effort not to contaminate your rock from space, though everyone knows that accidents sometimes h
appen. Ralph has probably already put you at your ease about this. ‘I ran over one last year,’ he sometimes says. ‘Someone was waving and saying “I found one”. I looked over there and then felt a crunch. Ouch. I found one, too.’

  You fold the top of the bag over several times, slip the aluminium number into the top of the bag and roll it over a few more times for luck. Now you use tape from the side pocket to seal the bag tightly. (Don’t forget to fold the end of the tape over so it’s easy to find next time, or you’ll be awarded the ‘white badge of shame’, a length of tape stuck to your parka for the rest of the day.)

  Now’s the fun part, the chance to look at the meteorite in detail and see what you’ve got. You might get your hand lens out to have a closer look. You note down its size, its description, if there seems anything unusual about it. These field notes will dictate what order the meteorites are opened in, when they have gone from a frozen boat to a frozen truck to the lab in Houston. A helpful clue for the curators is how many exclamation marks you add. Use of capital letters is also a clue. One meteorite hunter once wrote: ‘ABUSE ME FIRST!!!!!! Very, very, very sexy’ in the field notes for a rock he had found. It did indeed turn out to be a special one, though that’s another story.

  But even if you’ve found a meteorite that turns out to change the world of science, you’re not supposed to claim the credit. It’s just the luck of the draw—anyone could have found it. And for morale purposes within the group you have to stick to your lane. If you see something enticing on someone else’s patch, there’s strictly no poaching.

  When you have finished bagging and inspecting your find, the meteorite goes into the pack and everyone returns to their posts and starts up again. Days can be long, and the constant concentration wears you down. But you still have to save some energy for the chores back at the camp. Before bed you’ll need to dry your gloves and socks, fuel up and cover your skidoo ready for morning, fill up an ice bucket for water, and pull food from the frozen stores for dinner. Unlike many camps, ANSMET doesn’t take a cook or a communal tent. You’ll be sharing a pyramidal Scott tent with one other person, and you’ll cook together over a primus stove, wedged between your two sleeping areas, bathed in a cheerful orange glow as the twenty-four-hour daylight filters through the canvas. Space in the tents is tight. By the end of the trip you’ll be more blasé about bodily functions than you’ve ever been before, and you’ll have got to know your tent mate very well.

  The ability to relax is also a key part of the camp requirements. When the weather closes in you have to be able to let go of your frustrations, listen to music, read trashy novels, drink the camp drink—cocoa with a splash of Amaretto—and be as unproductive as you can. Email access is banned because it sucks up too much energy. For the six weeks or so the volunteers are out on the ice, this job will take every ounce of concentration they have.

  In the thirty-plus years since it began, ANSMET people have found more than 20,000 meteorites. Add these to the ones found over the same period by people in Japanese and European programmes and the Antarctic total is more than 50,000. Even though many of these are probably fragments of the same rocks, that’s more meteorites in a few decades than have been found in the rest of the world in two centuries.

  One reason, of course, is that in Antarctica there are no trees, plants, roads or soil to obscure the view. On the ice, everything stands out. And the meteorites that land there can stay deep-frozen and unchanged for hundreds of thousands, even millions, of years (unlike, say, in the warm wet environment of London, where they would disintegrate in just a few decades).

  But there’s another reason that Antarctica is such a treasure trove for meteorites. The ice doesn’t just collect them—it carefully concentrates them and presents them conveniently to the world. All this was figured out back in the 1980s by the founder of ANSMET, Bill Cassidy, a meteorite scientist from the University of Pittsburgh in Pennsylvania. Even in the early days of the programme Bill realised that Antarctica was special when it came to meteorites. There were places where you could pick them up by the bucketload. And all of these had exposed blue ice at the surface.

  That’s strange in itself. Though most of the continent is made of ice, up on the plateau it’s usually buried under tens or hundreds of metres of snow. Unless you dig very deep, you’ll rarely touch the blue stuff.

  But scattered around the continent there are a few surface ice fields, pale blue against the white. They usually form when there’s an obstruction beneath, a buried mountain range, say, or just an isolated hidden peak. As the ice flows out from the centre of the continent it hits the obstruction and rears up; strong surface winds then scrape off layer upon layer of snow until the ice itself emerges into the sunlight.

  Bill Cassidy noticed that this was where the meteorites were, and he thought he knew why. The flow of the ice was like an in-built winnowing mechanism, concentrating the meteorites in just a few places. Over thousands ofyears meteorites fall randomly, are buried by snow and squashed together deep below the surface. Next, ice from different regions unites as it flows to the outer edges of the ice sheet, concentrating the meteorites further. Around most of the continent, snow, ice and meteorites eventually tumble into the sea. But in certain places the ice runs against a mountain range, and is forced to the surface in those blue patches, carrying its load of meteorites with it.4

  If the mountain is fully buried, the only rocks you’ll find on the surface must have come from space. But in some cases the tip of the mountain range pokes through the surface, scattering terrestrial rocks to confuse the picture. In that case, part of the training involves getting your eye in—learning to spot the rocks that are different from the crowd.

  Ralph took over from Bill and has been running the ANSMET programme since 1996. But the first meteorite hunter that I met on the ice, John Schutt, goes back even farther. He has been working continuously for ANSMET since 1981 and—though he’d never admit it—he’s probably the most experienced meteorite hunter on Earth.5

  It was almost the end of the season when we met.6 I’d been eager to join the meteorite posse on a hunt but they were long gone by the time I reached the ice. But John was still around tidying up a few things, and he took pity on me. He had to go and pick up a few bits of equipment from the Allan Hills Main Icefield. Did I want to tag along?

  There was nothing standard issue about John Schutt. His shaggy brown beard was streaked with white, and strands of hair had escaped his ponytail and were jutting disreputably from beneath a faded baseball cap. His wind pants, enlivened with a crazy patchwork of red, orange and grey where the fabric had repeatedly frayed, proclaimed him as one of the oldest hands on the continent.

  Our expedition wasn’t, strictly speaking, a meteorite hunt. The Main Icefield had been picked over dozens of times so the chances of finding anything that someone had missed seemed remote. Worse, this was one of the sites with terrestrial rocks to confuse the eye. The ice butted up against the visible tip of a mountain and the field was already scattered with a disheartening array of earthly rocks, pebbles and stones. Muttering to myself about needles and haystacks, I climbed out of the helicopter to join John, who had leapt out while the rotors were still turning. Clearly his blood was up. ‘There are meteorites around here,’ he declared. ‘I can smell them!’

  The helicopter pilot, Barry James, was as curious as I was to see a real meteorite, and I waited for him to shut down and climb out of his seat. From up ahead John beckoned us over. ‘Here, look at these,’ he said and thrust out his hands containing two small pebbles. We studied them obediently. One was pale with very fine crystals, the other darker, packed with large crystals. ‘The meteorites we’re looking for won’t look anything like these,’ he said, and tossed them over his shoulder.

  We all started casting around among the stones. Suddenly John dropped full length on to the ice, lifting his glasses to peer intently at a small rock. Barry and I held our breath. ‘Nope,’ said John. ‘That’s a leavitrite,’ and he stood u
p and dusted himself off. ‘Leave it right there?’ Barry hazarded. ‘You got it,’ John replied briskly, and set off again.

  John’s clowning had lifted my mood and my optimism was soaring. It began to seem almost inevitable that we were going to find a meteorite, in spite of the odds. Our best chance was to find the most common kind of meteorite, an ‘ordinary chondrite’. It would have medium-sized crystals, in between those we’d just seen in the terrestrial stones. But it would also contain tiny spheres called chondrules. No one knows what these are, but they come from the very earliest days of the Solar System, before the Sun or planets had even formed. They probably started out as patches of space dust that were flash-melted by a sudden burst of energy and then cooled into a rain of solid droplets.

  Plenty of things could have supplied the energy. My favourite theory is that it came from an exploding star—a supernova. I like this because that same explosion may also have been the kick needed to make a random cloud of dust and gas start whirling and coalescing into our Sun, and planets. There are no chondrules left in terrestrial rocks. Anything here on Earth has been cooked, melted and fried by billions of years of grinding tectonic plates and volcanic outbursts and the chondrules are long gone. But most asteroids are too small to have all this activity, so chips off these particular blocks still bear the fingerprint of the stuff that gave birth to our worlds.

  The biggest clue to a meteorite, though, would be its fusion crust, the molten outside layer formed as it tore through the atmosphere in a blaze of heat and light. Fusion crusts are usually very dark brown and uniform, somewhere between glossy and matt, as though someone had painted a layer of dark chocolate on the outside. At its simplest, the rocks around us were mainly pale, and we were looking for something dark.