He pauses. I wait. Trillions of neutrinos pass through our bodies and on through the Earth’s bedrock, its mantle, its liquid innards, its solid core.
‘Imagine watching a game of billiards in which the red balls are visible but the white isn’t. Suddenly you see the red ball – an electron – move across the baize. By plotting the red ball’s path, you might be able to backtrack, as it were, the path of the invisible white ball – the WIMP – that struck it. And from this, you might be able to learn more about the direction, mass and qualities of that white ball. We’re looking to do this enough times, and with enough precision, to provide the signature of a dark-matter halo.’
At the core of the DRIFT device is a steel vacuum vessel a cubic metre in volume, criss-crossed by a meshwork of ultra-thin, highly charged wires spaced a millimetre apart. If a WIMP collides with the nucleus of an atom of ordinary matter inside the chamber, it causes an ionization track, which the meshwork of wires both intensifies and records. The track can therefore be reconstructed in three dimensions, providing information about the type and origin of the colliding particle. The wires are held within a low-pressure gas, the low-pressure gas within a conductive chamber, the conductive chamber within a steel neutron shield – and the whole unit is held in a band of halite left by the evaporation of an ancient sea.
I will learn over the years ahead that many such Chinese-box structures, with their multiple containment protocols, characterize storage procedures in the underland, from the falcon-headed Canopic stone jars of ancient Egyptian burial practice – into which were placed the vital organs of the dead, and which were themselves encased in a painted wooden chest, itself encased in a tomb, itself encased in a pyramid – to the concentric sheathing of spent uranium pellets from nuclear reactors; the pellets placed within rods of zirconium, the rods encased in a copper cylinder, the copper cylinder encased in an iron cylinder, the iron cylinder encased in bentonite clay rings, and the rings encased in the bedrock of a deep geological storage facility, sunk thousands of feet into gneiss, or granite, or salt.
Christopher leads me to his desk. The screensaver image on his computer is of the turquoise waters of Lake Louise in the Canadian Rockies. He shows me a diagram representing data returns from the Time Projection Chamber. It has lines of different bright colours, across which a fine black streak runs at an angle.
‘This diagonal line is the path of an alpha particle,’ Christopher says, following it with his little finger. ‘He’s a bludgeoning, portly gentleman who comes barrelling through our experiment, making a lot of noise as he goes. He’s not of interest to us, except insofar as identifying his signal helps us know what we’re not looking for.
‘What we’re trying to hear, instead, are the quiet whispers behind his boisterousness. Not even whispers, in fact; more like the faintest of breaths – of breathing. Down here in the salt is about the only place you could hear such breath. That breath is the sound of a weakly interacting massive particle passing through – and it leaves a fine trace. What we think is a WIMP-collision looks more like two small blips, one on each of two channels.’
With his fingernail he picks out two dots: one on a yellow line, one on pink. He pauses. His screensaver changes to an over-saturated image of a white-sand beach with palm trees, lapped by a lapis-lazuli sea. The WIMP wind from Cygnus blows through our bodies.
‘This data is very beautiful once you get used to it,’ he says. I nod in agreement.
‘Right now,’ Christopher says, ‘you are looking into the absolute smallness of the universe with pinpoint accuracy, peering down at the most minute of scales. Those coloured lines are our magnifying lens.’
Then he says – as if the phrase has just entered his head without warning, scoring a trace as it passes through – ‘Everything causes a scintillation.’ He pauses.
‘Why are you searching for dark matter?’ I ask.
‘To further our knowledge,’ Christopher replies without hesitation, ‘and to give life meaning. If we’re not exploring, we’re not doing anything. We’re just waiting.’
He pauses again. I wait. The screensaver on his computer changes to Yosemite in the autumn, with early snow on the top of El Cap. Christopher does not speak.
‘Is the search for dark matter an act of faith?’ I ask him.
He waits for me to elaborate – he has heard the question before, wants more before he answers. His screensaver changes to the desert dunes at Sossusvlei in Namibia.
I think of Rievaulx Abbey west of Boulby, where in a fertile river valley Cistercian monks founded and built a space in which to hold Mass. Out of ironstone they made an airy structure of soaring buttresses and vaulted ceilings. Their abbey was one among a network of such sites spread around the world, in which prayers were offered to a presence disinclined to disclose itself to the usual beseechings.
On the hillsides above the abbey geological forms known as ‘slip-rifts’ slowly open and close in the rock, emitting warm air from deep within the earth, such that on cold days the hillside itself appears to be breathing – as if the land itself were alive. Thousands of years before the Cistercians arrived in those valleys, Neolithic and Bronze Age peoples entered the darkness of the slip-rifts to carry out rituals that may have been sacrificial and were surely devotional, interring body parts amid the stones of the rifts; another kind of annihilation product.
I remember the Wind Cave system in the Black Hills of South Dakota, sacred to the Lakota Sioux people and close to the American dark-matter detection laboratory set deep in the worked-out gold mine. From the opening to Wind Cave, which extends for more than 130 miles below ground, air rushes or is drawn with such force that it can strip hats from heads. In the Lakota creation stories it is from Wind Cave that humans first emerge into the upper world, where they are astonished by colour and space.
‘My sense,’ I say to Christopher, ‘is that the search for dark matter has produced an elaborate, delicate edifice of presuppositions, and a network of worship sites, also known as laboratories, all dedicated to the search for an invisible universal entity which refuses to reveal itself. It seems to resemble what we call religion rather more than what we call science.’
‘I grew up as a very serious Christian,’ Christopher says. ‘Then I lost my faith almost entirely when I found physics. Now that faith has returned, but in a much-changed form. It’s true that we dark-matter researchers have less proof than other scientists in terms of what we seek to discover and what we believe we know. As to God? Well, if there were a divinity then it would be utterly separate from both scientific enquiry and human longing.’
He pauses again. It is not that this thinking is hard for him – he has moved down these paths before – but that he is picking each word with care.
‘No divinity in which I would wish to believe would declare itself by means of what we would recognize as evidence.’ He gestures at the data read-out. ‘If there is a god, we should not be able to find it. If I detected proof of a deity, I would distrust that deity on the grounds that a god should be smarter than that.’
‘Does it change the way the world feels?’ I ask him. ‘Knowing that 100 trillion neutrinos pass through your body every second, that countless such particles perforate our brains and hearts? Does it change the way you feel about matter – about what matters? Are you surprised we don’t fall through each surface of our world at every step, push through it with every touch?’
Christopher nods. He thinks. His screensaver changes to the limestone towers at Guilin, seen near dusk such that they are backlit in ways that are considered widely appealing on Instagram and other large-scale image-sharing platforms.
‘At the weekends,’ Christopher says, ‘when I’m out for a walk with my wife, along the cliff tops near here, on a sunny day, I know our bodies are wide-meshed nets, and that the cliffs we’re walking on are nets too, and sometimes it seems, yes, as miraculous as if in our everyday world we suddenly found ourselves walking on water, or air. And I wonder what it must
be like, sometimes, not to know that.’
He pauses, and it is clear that he is thinking now beyond the confines of the salt cavern, beyond even the known limits of the universe.
‘But mostly, and in several ways, I’m amazed I’m able to hold the hand of the person I love.’
~
Neil wanted to drive the Paris–Dakar Rally back in the day. Neil is steering a stripped-down doorless Ford Transit van in a subterranean desert maze more than 600 miles in extent, Neil is a matter of weeks from retirement, and Neil doesn’t give a shit.
We take the ramps fast enough to lift up as we come over them. We leave the tunnels behind us clouded with dust. Instead of slowing down for the corners, Neil just leans on the horn. Paaaaarp! He’s a man passionate about mine safety; he’s also a man passionate about fun. I like him a lot.
I hang off the roof handle with my left hand, lean forwards and brace myself with my right hand against the dashboard. I clench my jaws to stop my teeth clattering.
‘Between the main shaft, where the lab sits, and the production districts, there’s barely anyone except at shift change,’ says Neil. ‘If they’re coming our way, we should see their lights from a long way off.’
The roadways are cut from the halite, with ramps leading up into the potash seams. The sides of the roadways glimmer a little in the light, like ice. We’re trucking through pure salt. The tunnels are of standard dimensions – 3.8 metres high, 8 metres wide – and their ceilings are regularly reinforced with bolts the length of a man, to slow the slump.
‘The potash is more fissile,’ says Neil. ‘Cracks more easily. You don’t want to run roadways through it unless you have to. Halite tends to sag rather than shatter. Much safer.’
Thump! Paaaaarp!
‘These main roadways have two years or so in them before they start to scrunch up. We prop them up with wood stacks. Wood’s better than steel: it squishes rather than snapping. Much safer. Still, sometimes we lose a district before it’s mined out. So it goes.’
Neil has a disconcerting habit of turning to me as he talks, keeping one hand on the top of the wheel but no eyes on the road. Sometimes he rotates the steering wheel with his palm, as though he is buffing a car’s panel work in small arcs. Wax on, wax off. ‘It’s not like a coal mine, where you’re always worried about combustion of the coal dust in the air,’ he says. ‘Here the salt dust acts like a dry-powder fire extinguisher. Much safer.
‘The last death down here was in the 2000s, caused by a low-velocity explosion at the production face: 500 tons of rock came down in a recently mined roadway, pushed the machine back, and the machine crushed a man to death. No one’s died down here this decade.’
A few months later a popular miner called John Anderson will be killed in a gas blowout.
We ramp up into a potash seam. Neil brakes the van to a halt in a swirl of dust, jumps out, cracks a fat flake of potash off the tunnel wall and hands it to me. It is pink as meat and flecked with silver mica. It is surprisingly light, almost buoyant in the hand.
‘Lick it,’ says Neil. It fizzes on my tongue. It tastes of metal and blood. I want to eat it all.
A stream of water runs down a wall of the tunnel from a crack in the ceiling. Neil points upwards. ‘We’ve just crossed the coastline! We’re under the sea now!
‘Halite and sylvite are both soluble in water,’ says Neil. ‘This poses problems when you mine below the ocean. We have to pump the mine continuously to keep it workable: 1,000 gallons a minute, giving us an electricity bill of about £3 million per year. The Russians and the Canadians have both lost potash mines to flooding in the past.
‘We had a big flood not so long back: 3,500 gallons a minute, running for eight weeks. We thought we’d lost the mine for a while. Then it slowed as it self-sealed; don’t quite know why. Nothing to say it won’t start up again.’
‘How reassuring.’
We get back into the Transit. ‘How’s this for a job, eh?’ Neil asks no one in particular. ‘I get paid to do this!’ He slams the pedal to the metal, we lurch back in our seats and hammer on down the drift.
Neil’s navigational powers impress me. He has no map, there are no signs, but he shows no hesitation at any of the dozens of junctions we meet.
‘If you were to die,’ I say, ‘just hypothetically speaking, how would I get out of here?’
‘If in doubt, follow the wheel tracks,’ he yells. ‘And if I cop it, just keep the wind in your face and you’ll find the way out!’ He points up again. ‘We’re out beyond the shipping lane now. Imagine those captains in charge of their boats, with never a clue we’re careering about below them!’
It takes us another twenty minutes to reach the production face. Neil parks at the side of a tunnel, behind two other transits, straightening up the wheels as neatly as if he is on a suburban street.
Dust smogging the air; the tunnels ahead forking out; flickering lights and shadow-movement. The walls of the tunnels are inscribed with gouged patterns: spirals, cross-hatchings. They look like the cuts of a creature trying to claw its way out of a trap, or the ritual petroglyphs of a tribe.
‘Production District 887 – the limits of the seam,’ says Neil. ‘The test-probes suggest the seam exhausts itself more or less here. Once this district is mined out, there’ll be no more north-westwards progress; we’ll look to the eastern and south-eastern edges of the undersea drift.’
Two teams of men are sitting at tables, drinking and eating. In the blackness I can see only the glowing strips of their hi-vis jackets. It’s a scene from Tron. The men look up, nod a greeting, get back to their food. There are dozens of penises scrawled in biro and marker pen on the white wipe-clean PVC of the tabletop.
Left down one tunnel, right down another. Noise increasing; dust increasing. Halogen light-beams slice through choking air. Screaming noise of metal on mineral.
A huge red-black machine, low-slung and sharp-toothed as a Komodo dragon, is feeding at a face of rock. The dragon is controlled via a thick black rubberized cable, as if on a dog leash. From the lizard’s arsehole extrudes a long thin stream of potash ore on a conveyor belt, ducted back towards a hopper to begin its journey to the world’s fields.
The lizard-machine feeds at the face, the conveyor belt continues to trundle ore towards the hopper, and I am struck by a sense of the creatureliness of the mining operation: the avid clawing at the rock, the tunnel network that has been created. I remember cross-sections I have seen of the interiors of termite mounds and ants’ nests, rabbit warrens and mole runs. Neil’s map of the mine, with its hundreds of miles of intersecting drift, is just the plan of another animal’s burrow-complex, bored out in search of resources.
What curious partners they have become in the darkness, the mine and the laboratory, oddly echoic of each other’s operations. The geologists sending their probes out into the rock ahead, hoping to detect and pursue the most remunerative seams. The physicists watching for the arrival of knowledge, pure knowledge, the sylvite of knowledge, hard to reach, worth nothing, hoping to detect the missing portion of the universe: dark matter, a yield that cannot be sold.
Neil leans close again, cups his hands to shout into my ears above the noise of extraction. ‘Those face-mining machines? They cost £3.2 million each. The engines are modified, obviously, to prevent sparking. We bring them down in sections in the lift shaft, assemble them in build-up bays, and then drive them out to the production face, towing a generator behind them. It takes them three days to trundle the seven or so miles out here to where they begin work.’
The strains of the work are intense, the lifespan of the machines short. ‘When one of them reaches the end of its useful days,’ says Neil, ‘it’s not cost-effective to bring it back up. It’d take the place of ore in the upshaft, and that’s too expensive. So instead the machine gets driven into a worked-out tunnel of rock salt, and abandoned there. The halite will flow around it as the tunnel naturally closes up.’
It is an astonishing image: the
translucent halite melting around this cybernetic dragon – the fossilization of this machine-relic in its burial shroud of salt.
I remember the pit ponies about which Emile Zola had written, brought down as foals into France’s great nineteenth-century coal mines. The foals would not see daylight again. They grew in the mines, were fed there, were worked to death there, and their stunted bodies were left in side tunnels, awaiting the burial of collapse.
In the halite strata that underlie the New Mexico desert, an underground facility known as the Waste Isolation Pilot Plant has been excavated, designed for the long-term disposal of transuranic radioactive waste arising from the research and production of nuclear weapons. More than 2,000 feet below the desert surface, a burial site has been created for thousands of silver steel drums packed with nuclear waste. Because the waste remains radioactive for thousands of years, it generates heat. This heat will increase the plasticity of the halite – and so once each chamber is replete, the warmed halite should creep around the barrels, securing them for the deep time future.
I am briefly filled with a longing to step into a side tunnel myself, lie down and let the halite slowly seal me in for five years or 10,000 – to wait out the Anthropocene in that translucent cocoon.
~
In 1999, at a conference in Mexico City on the Holocene – the epoch of Earth history that we at present officially inhabit, beginning around 11,700 years ago – the Nobel Prize-winning atmospheric chemist Paul Crutzen was struck by the inaccuracy of the Holocene designation. ‘I suddenly thought this was wrong,’ he later recalled. ‘The world has changed too much. So I said, “No, we are in the Anthropocene.” I just made the word up on the spur of the moment. But it seems to have stuck.’
The following year, Crutzen and Eugene Stoermer – an American diatom specialist who had been using the term informally since the 1980s – jointly published an article proposing that the Anthropocene should be considered a new Earth epoch, on the grounds that ‘mankind [sic ] will remain a major geological force for many millennia, maybe millions of years to come’. As the Pleistocene was defined by the action of ice, and the Holocene by a period of relative climatic stability allowing the flourishing of life, so the Anthropocene is seen to be defined by the action of anthropos: human beings, shaping the Earth at a global scale.
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