Antarctica (23 page)

That's not all. Astronomers believe that at the true centre of the Galaxy, the point that everything else was rotating round, lies a supermassive black hole, some four million times heavier than the Sun. At the moment this is quiescent. Rather than performing the usual black hole habit of sucking in all the material around it, it is starved of nearby fuel and hence effectively switched off. But if the star formation kicked off, new material would fall into the black hole's vicinity, activating it into a voracious monster. As dust and gas were dragged inwards, an accreting ring around it could shine like a thousand Suns, and giant jets of recycled stuff could burst out of its north and south poles and shoot out in magnetic maelstroms above and beyond the rim of the Milky Way and into intergalactic space. All of this would be hidden from us even if it were happening now, blocked by all the clouds in between. ‘But if you had radio eyes it would be fireworks.'
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This was very dramatic, of course. But there was another more intimate reason why we should care about molecular clouds and bursts of newly formed stars. Tony called it the ‘ecology of the Galaxy'. As molecular clouds collapse into stars, some of the stars live much longer than others. But all in the end will die, either in massive explosions—supernovas—or in a gradual loss of form as the outermost parts are gently blown outwards in a streaming wind. And the material thrown out in this way goes on to make new molecular clouds, and ultimately new stars and planets.

So our Galaxy is one massive exercise in recycling, mingling and reforming. But there's more. From what we now understand about the lives of stars, we can tell where the material in our own Solar System came from. And that shows something extraordinary. Not only are we all made of stardust, but we are made of the dust from
different
stars. All the material around you—this book, your clothes, the tea bag that Tony Stark had just taken out of his mug—is made up of atoms that have been processed and recycled through a succession of stars. So has every atom in your body. And some of your atoms have been through a different set of stars than others.

‘So I have atoms next to each other in my body that have come from different stars, from different parts of the Galaxy?'

‘Yes.'

‘That is really spooky.'

‘That's what star formation does.'

Tony said all this in a matter-of-fact way. Perhaps he had grown used to it, the way he has grown used to the scale of the Galaxy. But I couldn't. Even now, every time I think of this, it still blows my mind.

Tony no longer spends winters at the Pole, but there are plenty of others who do. Unlike Larry and the other construction workers (whom he described as ‘indoor cats'), the astronomy technicians have no choice but to leave the comforts of the station and make the daily trek to the Dark Sector where the telescopes await their attention.

German technician Robert Schwarz, a self-styled ‘telescope nanny', was about to embark on his fourth winter. His hair was close-cropped, and he was inclined to be terse. (Typical conversation: ‘What's it like here in the winter?' ‘Cold, and dark.') He had last year off, but had come back to the Pole to work on one of the biggest imaginable questions: the origin of the Universe.

Robert's telescope would be picking up the faint afterglow of the Big Bang itself. For the first few hundred thousand years after the Big Bang the entire Universe glowed hotter than the Sun. A roiling plasma of negatively charged electrons and positively charged ions circled around each other, eager to join forces and become neutralised, and yet constantly breaking apart as soon as they united, because of the searing heat. And all was bathed in a brilliant blaze of light.

Eventually, as the Universe stretched and cooled, the electrons and ions fell into each other's arms to become the atoms that make up the stars, the planets, and us.
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And the light streaked out across the Universe, bearing the slightest, almost imperceptible traces of erstwhile lumps in the cosmic maelstrom, here the light a little denser, there a little more insubstantial. This faint glow is still out there, its elongated wavelengths now too far from the visible rainbow for human eyes to see. But with the right telescope, in the right place, you can see through the dirty window of the Earth's humid air and pick out, if you look hard enough, those traces of primordial structure. And if you do, you can calculate nothing less than the mass of the entire Universe.

Astronomers call the afterglow of the Big Bang the ‘Cosmic Microwave Background' (CMB). ‘Background' because it exists in every direction in the sky; it is the canvas on which all the stars and galaxies are painted. ‘Microwave' because the light that was once visible has now been stretched into roughly the same patch of the spectrum as the microwaves that power your oven, though it is feeble enough not to burn us all to a crisp. And ‘Cosmic' because, well, that's what it is.

As for AST/RO, Robert and the other CMB researchers need air that is as devoid as possible of water. But unlike AST/RO they need to look away from the main body of the Galaxy—what the starburst people see as nascent star nurseries, the microwave background people dismiss as ‘galactic smog'. Instead, the CMB researchers angle their telescopes to look up and out of the flat plane of the Galaxy, where there are no spurs or arms or patches of molecular clouds to spoil the view. And then, thanks to the thin dry air at the Pole, the CMB researchers find themselves looking through one of the cleanest patches of sky in the world.

It's not perfect. To get the best results you need to look at the largest possible area—ideally the whole sky. As the Earth spins on its axis, a telescope at the equator sweeps through a huge area of sky every twenty-four hours, whereas the South Pole rotates constantly beneath the same relatively small patch. But with the long, cold, steady winters you can bore into that patch very deeply.

Back in 1998 a South Pole telescope called VIPER, the brainchild of University of Pittsburgh researcher Jeff Peterson, performed measurements on the Microwave Background and picked up those almost imperceptible traces of ancient clumping. Added in with data from a telescope in the arid Atacama Desert in northern Chile, and a couple of balloon flights that set off from McMurdo and made long, slow circles around the Pole, the researchers came up with a number for the mass of the Universe. The answer was:

 

100 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 tonnes.

 

Give or take a few pounds.
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Now the astronomers wanted to go deeper, to find out what the Microwave Background could tell us about the structure of the Universe, the strange invisible ‘dark energy' that it seems to be filled with, how it truly began, and how it is likely to end. Next winter, Robert would be working on a new CMB instrument, and plans were already under way to build a whopping 10-m telescope here, the South Pole Telescope, that would have nothing but the Microwave Background in its sights.

Robert's friend and fellow telescope nanny Steffen Richter, who was also German, would be on a much weirder kind of telescope called AMANDA, which stood for Antarctic Muon and Neutrino Detector Array.
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Unlike the other telescopes, which all looked like oversized TV satellite dishes, AMANDA was completely invisible. It was made up of strings of detectors that were buried hundreds of metres down in the ice. Any day now, construction was going to begin on a much bigger device called Ice Cube because it would stretch over a full cubic kilometre of ice, with AMANDA making up one small corner of this behemoth.
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Both these telescopes were for studying spectacular astronomical occurrences: exploding stars, colliding black holes, gamma-ray bursts and the rest of the Universe's biggest and most cosmic bangs. These all generate debris in the form of particles. But to do astronomy, you need to know exactly where they came from. And as they travel through space, most are hopelessly wayward. Cosmic rays are charged, so can be dragged about by any stray magnetic field. Free-flying neutrons fall apart within minutes.
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The only particles whose subsequent path through the Universe is straight and true are tiny, chargeless, faceless creatures called neutrinos.

However, the same thing that makes them come to us so directly also makes them very hard to detect. Neutrinos don't stop for anybody or anything. A magnetic field can't turn them, gravity doesn't bother them and they zip through solid objects without a backward glance. Trillions of neutrinos pass through your body every second. They are doing it now, and have been ever since you were born, but in your entire lifetime the chances are that only one of these will stop to wipe its feet.

Still, if you look for long enough, over a wide enough area, you can sometimes catch a neutrino in the act. Once in a very rare while a cosmic neutrino will crash into something—an atom of air, say, or of ice—and spit out another particle called a muon, which announces its presence with a tiny burst of blue light. Measuring this light will tell you exactly what direction the neutrino was coming from and how much energy it had. And that in turn will give a hefty clue about where and how it was created.

The problem is that cosmic neutrinos aren't the only things that create muons. In fact, the sky is filled with the wrong kind of muons. For every tiny burst of blue light from a genuine intergalactic messenger, there are a billion flashes from common- or-garden cosmic rays. Picking out that one in a billion is all but impossible.

What's really clever about both AMANDA and Ice Cube is that they were designed not to look up, but to look down. The idea is to use the Earth's rocky body as a sort of gigantic sieve. Of all the useless muons generated in the far-off northern skies, only one in a million will make it through the centre of the Earth to this, the southern side. But all the neutrinos will slip through unscathed. Now the odds are more favourable. Using Earth as a filter means that you generate one special neutrino-derived muon for every thousand dud ones. And those are the kinds of numbers that astronomers can handle.

The strings of detectors that make up Ice Cube would be sunk down more than a kilometre and a half, to reach the depths where the dark ice was at its purest and most transparent. It would cost $270 million, so much, in fact, that it required its own line in the Congressional budget (though the researchers point out on their website that, if you count in the ice as well, this amounts to a mere twenty-five cents per tonne).

When it is fully operating, Ice Cube should pick up several hundred cosmic neutrinos a year, which should be enough to do some exciting physics. In a way, neutrinos are the latest in a long line of new ways of seeing the Universe. Prehistoric humans started off by looking at the visible light that shone from the stars; since then we have invented ways to pick up X-rays, gamma rays, radio, microwaves and now neutrinos; and each new way of looking told us more about the sky above us. The more literary of Ice Cube's proponents are fond of quoting from Marcel Proust: ‘The real voyage of discovery consists not in seeking new landscapes, but in having new eyes.'

Unlike Tony Stark, I sensed that both Robert and Steffen cared about the landscape and the experience of the Pole at least as much as the science itself. In the end both of them told me certain stories about their experiences, but they were also guarded. They didn't particularly want to share. During all our conversations, the message came through loud and very clear. They would readily tell me about the cold of an Antarctic winter, but not about its heart.
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South Pole winter, March-May

 

When the darkness has finally fallen, and the temperatures are too cold for skidoos, the only way to get to the Dark Sector is to trudge. The walk takes twenty minutes, maybe half an hour, in pitch black, as winds rise to 20, 30 or 40 knots and the temperature falls to mind-numbing depths. The telescope nannies will make this return trek at least once a day, sometimes twice. And that's just fine with them. ‘Some years ago they talked about making a tunnel to the Dark Sector,' Steffen says. ‘No way. We like to commute.'
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The snow crunches under your feet. Construction workers often just wear normal work boots to dash between buildings; then the snow sticks to the soles and quickly accumulates into a dense ice layer, turning the boots into towering tap shoes. But for the journey out to the Dark Sector you need bunny boots, which slough off the snow, and have a trapped layer of insulating air to keep out the cold in all but the worst conditions.

As the temperature slips down towards -76°F you start to hear your breath freezing. The sound is like blowing softly through into a piece of paper held up to your face, and making it reverberate. Hhhhhhwwwwwoooohhh. And your breath hangs in the air as a frozen cloud of ice blocking your view. If you're working outside you have to blow to one side, and then work for a little while, and then blow to one side, and then work again.

And all the time you are watching out for the signs of frost nip, the milder cousin of frostbite. Frost nip is basically a burn, but it's impressive how much it hurts. First your skin goes white and numb and then, when the blood rushes back in, you feel as if someone has hit your hand hard with a hammer, or as if an elephant has crushed your toes.

If you ignore the frost nip long enough it will become frostbite, the stuff that blackens your skin and takes first your fingers and toes and then entire limbs. When you finally make it to the Dark Sector buildings, people will inspect your face and hands for white patches. You're supposed to look out for each other. Frost nip is not something to take lightly. ‘At home in the mountains you might get a bit numb,' says Steffen, ‘but you won't start losing body parts.'