by Bill Bryson
The assumption he made—rather a large one, but correct as it turned out— was that many meteorites are essentially left-over building materials from the early days of the solar system, and thus have managed to preserve a more or less pristine interior chemistry. Measure the age of these wandering rocks and you would have the age also (near enough) of the Earth.
As always, however, nothing was quite as straightforward as such a breezy description makes it sound. Meteorites are not abundant and meteoritic samples not especially easy to get hold of. Moreover, Brown’s measurement technique proved finicky in the extreme and needed much refinement. Above all, there was the problem that Patterson’s samples were continuously and unaccountably contaminated with large doses of atmospheric lead whenever they were exposed to air. It was this that eventually led him to create a sterile laboratory—the world’s first, according to at least one account.
It took Patterson seven years of patient work just to find and measure suitable samples for final testing. In the spring of 1953 he took his specimens to the Argonne National Laboratory in Illinois, where he was granted time on a late-model mass spectrograph, a machine capable of detecting and measuring the minute quantities of uranium and lead locked up in ancient crystals. When at last he had his results, Patterson was so excited that he drove straight to his boyhood home in Iowa and had his mother check him into a hospital because he thought he was having a heart attack.
Soon afterwards, at a meeting in Wisconsin, Patterson announced a definitive age for the Earth of 4,550 million years (plus or minus 70 million years)—“a figure that stands unchanged 50 years later,” as McGrayne admiringly notes. After two hundred years of attempts, the Earth finally had an age.
Almost at once, Patterson turned his attention to the question of all that lead in the atmosphere. He was astounded to find that what little was known about the effects of lead on humans was almost invariably wrong or misleading—and not surprisingly, since for forty years every study of lead’s effects had been funded exclusively by manufacturers of lead additives.
Clair Patterson swabbing down his laboratory at Caltech. Mysterious but chronic contamination from atmospheric lead repeatedly spoiled his experiments. (credit 10.8)
In one such study, a doctor who had no specialized training in chemical pathology undertook a five-year programme in which volunteers were asked to breathe in or swallow lead in elevated quantities. Then their urine and faeces were tested. Unfortunately, as the doctor appears not to have known, lead is not excreted as a waste product. Rather, it accumulates in the bones and blood—that’s what makes it so dangerous—and neither bone nor blood was tested. In consequence, lead was given a clean bill of health.
Patterson quickly established that we had a lot of lead in the atmosphere—still do, in fact, since lead never goes away—and that about 90 per cent of it appeared to come from car exhaust pipes; but he couldn’t prove it. What he needed was a way to compare lead levels in the atmosphere now with the levels that existed before 1923, when tetraethyl lead began to be commercially produced. It occurred to him that ice cores could provide the answer.
It was known that snowfall in places like Greenland accumulates into discrete annual layers (because seasonal temperature differences produce slight changes in coloration from winter to summer). By counting back through these layers and measuring the amount of lead in each, he could work out global atmospheric lead concentrations at any time for hundreds, or even thousands, of years. The notion became the foundation of ice core studies, on which much modern climatological work is based.
What Patterson found was that before 1923 there was almost no lead in the atmosphere, and that since that time lead levels had climbed steadily and dangerously. He now made it his life’s quest to get lead taken out of petrol. To that end, he became a constant and often vocal critic of the lead industry and its interests.
It would prove to be a hellish campaign. Ethyl was a powerful global corporation with many friends in high places. (Among its directors have been Supreme Court Justice Lewis Powell and Gilbert Grosvenor of the National Geographic Society.) Patterson suddenly found research funding withdrawn or difficult to acquire. The American Petroleum Institute cancelled a research contract with him, as did the United States Public Health Service, a supposedly neutral government body.
As Patterson increasingly became a liability to his institution, the Caltech trustees were repeatedly pressed by lead industry officials to shut him up or let him go. According to Jamie Lincoln Kitman, writing in The Nation in 2000, Ethyl executives allegedly offered to endow a chair at Caltech “if Patterson was sent packing.” Absurdly, he was excluded from a 1971 National Research Council panel appointed to investigate the dangers of atmospheric lead poisoning, even though he was by then unquestionably America’s leading expert on atmospheric lead.
To his great credit, Patterson never wavered. Eventually his efforts led to the introduction of the Clean Air Act of 1970 and finally to the removal from sale of all leaded petrol in the United States in 1986. Almost immediately lead levels in the blood of Americans fell by 80 per cent. But because lead is for ever, Americans alive today each have about 625 times more lead in their blood than people did a century ago. The amount of lead in the atmosphere also continues to grow, quite legally, by about a hundred thousand tonnes a year, mostly from mining, smelting and industrial activities. The United States also banned lead in indoor paint, “44 years after most of Europe,” as McGrayne notes. Remarkably, considering its startling toxicity, lead solder was not removed from American food containers until 1993.
Discarded refrigerators waiting for the CFCs in their cooling systems to be removed. Though banned in most of the developed world, millions of pounds of destructive CFCs, often made by Western companies, are still legally sold in the third world each year. (credit 10.9)
As for the Ethyl Corporation, it’s still going strong, though GM, Standard Oil and Du Pont no longer have stakes in the company. (They sold out to a company called Albemarle Paper in 1962.) According to McGrayne, as late as February 2001 Ethyl continued to contend “that research has failed to show that leaded gasoline poses a threat to human health or the environment.” On its website, a history of the company makes no mention of lead—or indeed of Thomas Midgley—but simply refers to the original product as containing “a certain combination of chemicals.”
Ethyl no longer makes leaded petrol, although, according to its 2001 company accounts, tetraethyl lead (or TEL as it calls it) still accounted for $25.1 million sales in 2000 (out of overall sales of $795 million), up from $24.1 million in 1999, but down from $117 million in 1998. The company stated in its report its determination to “maximize the cash generated by TEL as its usage continues to phase down around the world.” Ethyl markets TEL worldwide through an agreement with Associated Octel Ltd of England.
As for the other scourge left to us by Thomas Midgley, chlorofluorocarbons, they were banned in 1974 in the United States, but they are tenacious little devils and any that were loosed into the atmosphere before then (in deodorants or hairsprays, for instance) will almost certainly be around and devouring ozone long after you and I have shuffled off. Worse, we are still introducing huge amounts of CFCs into the atmosphere every year. According to Wayne Biddle, over 27 million kilograms of the stuff, worth $1.5 billion, still finds its way onto the market every year. So who is making it? We are—that is to say, many large corporations are still making it at their plants overseas. It will not be banned in third world countries until 2010.
Clair Patterson died in 1995. He didn’t win a Nobel Prize for his work. Geologists never do. Nor, more puzzlingly, did he gain any fame or even much attention from half a century of consistent and increasingly selfless achievement. A good case could be made that he was the most influential geologist of the twentieth century. Yet who has ever heard of Clair Patterson? Most geology textbooks don’t mention him. Two recent popular books on the history of the dating of the Earth actually manage to misspell his
name. In early 2001, a reviewer of one of these books in the journal Nature made the additional, rather astounding error of thinking Patterson was a woman.
At all events, thanks to the work of Clair Patterson, by 1953 the Earth at last had an age everyone could agree on. The only problem now was that it was older than the universe that contained it.
Probably the most expensive hole ever dug, the core of the Superconducting Supercollider stands empty and uncompleted in Texas. Designed to recreate conditions during the first ten thousand billionths of a second of the universe, the project was cancelled by Congress after 22 kilometres of tunnel had been dug and $2 billion spent. (credit 11.1)
MUSTER MARK’S QUARKS
In 1911, a British scientist named C. T. R. Wilson was studying cloud formations by tramping regularly to the summit of Ben Nevis, a famously damp Scottish mountain, when it occurred to him that there must be an easier way. Back in the Cavendish Lab in Cambridge he built an artificial cloud chamber—a simple device in which he could cool and moisten the air, creating a reasonable model of a cloud in laboratory conditions.
The device worked very well, but had an additional, unexpected benefit. When he accelerated an alpha particle through the chamber to seed his make-believe clouds, it left a visible trail—like the contrails of a passing airliner. He had just invented the particle detector. It provided convincing evidence that subatomic particles did indeed exist.
Eventually two other Cavendish scientists invented a more powerful proton-beam device, while in California Ernest Lawrence at Berkeley produced his famous and impressive cyclotron, or atom-smasher as such devices were long excitingly known. All of these contraptions worked— and indeed still work—on more or less the same principle, the idea being to accelerate a proton or other charged particle to an extremely high speed along a track (sometimes circular, sometimes linear), then bang it into another particle and see what flies off. That’s why they were called atom-smashers. It wasn’t science at its subtlest, but it was generally effective.
As physicists built bigger and more ambitious machines, they began to find or postulate particles or particle families seemingly without number: muons, pions, hyperons, mesons, K-mesons, Higgs bosons, intermediate vector bosons, baryons, tachyons. Even physicists began to grow a little uncomfortable. “Young man,” Enrico Fermi replied when a student asked him the name of a particular particle, “if I could remember the names of these particles, I would have been a botanist.”
Today accelerators have names that sound like something Flash Gordon would use in battle: the Super Proton Synchrotron, the Large Electron-Positron Collider, the Large Hadron Collider, the Relativistic Heavy Ion Collider. Using huge amounts of energy (some operate only at night so that people in neighbouring towns don’t have to witness their lights fading when the apparatus is fired up), they can whip particles into such a state of liveliness that a single electron can do 47,000 laps around a 7-kilometre tunnel in under a second. Fears have been raised that in their enthusiasm scientists might inadvertently create a black hole or even something called “strange quarks,” which could, theoretically, interact with other subatomic particles and propagate uncontrollably. If you are reading this, that hasn’t happened.
An interior view of a cloud chamber, taken in 1932, providing early confirmation of the existence of neutrons. The white line shows the track of a proton recoiling after being struck by a neutron. The neutron, lacking an electric charge, leaves no track itself. (credit 11.2)
Finding particles takes a certain amount of concentration. They are not just tiny and swift but often also tantalizingly evanescent. Particles can come into being and be gone again in as little as 0.000000000000000000000001 of a second (10−24 seconds). Even the most sluggish of unstable particles hang around for no more than 0.0000001 of a second (10−7 seconds).
Some particles are almost ludicrously slippery. Every second the Earth is visited by ten thousand trillion trillion tiny, all-but-massless neutrinos (mostly shot out by the nuclear broilings of the Sun) and virtually all of them pass right through the planet and everything that is on it, including you and me, as if it weren’t there. To trap just a few of them, scientists need tanks holding up to 57,000 cubic metres of heavy water (that is, water with a relative abundance of deuterium in it) in underground chambers (old mines usually) where they can’t be interfered with by other types of radiation.
Very occasionally, a passing neutrino will bang into one of the atomic nuclei in the water and produce a little puff of energy. Scientists count the puffs and by such means take us very slightly closer to understanding the fundamental properties of the universe. In 1998, Japanese observers reported that neutrinos do have mass, but not a great deal—about one ten-millionth that of an electron.
(credit 11.3)
What it really takes to find particles these days is money and lots of it. There is a curious inverse relationship in modern physics between the tininess of the thing being sought and the scale of the facilities required to do the searching. CERN, the European Organization for Nuclear Research, is like a little city. Straddling the border of France and Switzerland, it employs three thousand people and occupies a site that is measured in square kilometres. CERN boasts a string of magnets that weigh more than the Eiffel Tower and an underground tunnel some 26 kilometres around.
Breaking up atoms, as James Trefil has noted, is easy; you do it each time you switch on a fluorescent light. Breaking up atomic nuclei, however, requires quite a lot of money and a generous supply of electricity. Getting down to the level of quarks—the particles that make up particles—requires still more: trillions of volts of electricity and the budget of a small Central American state. CERN’s new Large Hadron Collider, scheduled to begin operations in 2005, will achieve 14 trillion volts of energy and cost something over $1.5 billion to construct.1
But these numbers are as nothing compared with what could have been achieved by, and spent upon, the vast and now unfortunately never-to-be Superconducting Supercollider, which began construction near Waxahachie, Texas, in the 1980s, before experiencing a supercollision of its own with the United States Congress. The intention of the collider was to let scientists probe “the ultimate nature of matter,” as it is always put, by recreating as nearly as possible the conditions in the universe during its first ten thousand billionths of a second. The plan was to fling particles through a tunnel 84 kilometres long, achieving a truly staggering 99 trillion volts of energy. It was a grand scheme, but would have cost $8 billion to build (a figure that eventually rose to $10 billion) and hundreds of millions of dollars a year to run.
In perhaps the finest example in history of pouring money into a hole in the ground, Congress spent $2 billion on the project, then cancelled it in 1993 after 22 kilometres of tunnel had been dug. So Texas now boasts the most expensive hole in the universe. The site is, I am told by my friend Jeff Guinn of the Fort Worth Star-Telegram, “essentially a vast, cleared field dotted along the circumference by a series of disappointed small towns.”
Since the supercollider debacle, particle physicists have set their sights a little lower, but even comparatively modest projects can be quite breathtakingly costly when compared with, well, almost anything. A proposed neutrino observatory at the old Homestake Mine in Lead, South Dakota, would cost $500 million to build—this in a mine that is already dug—before even looking at the annual running costs. There would also be $281 million of “general conversion costs.” A particle accelerator at Fermilab in Illinois, meanwhile, cost $260 million merely to refit.
Particle physics, in short, is a hugely expensive enterprise—but it is a productive one. Today the particle count is well over 150, with a further 100 or so suspected, but unfortunately, in the words of Richard Feynman, “it is very difficult to understand the relationships of all these particles, and what nature wants them for, or what the connections are from one to another.” Inevitably, each time we manage to unlock a box, we find that there is another locked box inside. Some peop
le think there are particles called tachyons, which can travel faster than the speed of light. Others long to find gravitons—the seat of gravity. At what point we reach the irreducible bottom is not easy to say. Carl Sagan in Cosmos raised the possibility that if you travelled downwards into an electron, you might find that it contained a universe of its own, recalling all those science-fiction stories of the 1950s. “Within it, organized into the local equivalent of galaxies and smaller structures, are an immense number of other, much tinier elementary particles, which are themselves universes at the next level and so on forever—an infinite downward regression, universes within universes, endlessly. And upward as well.”
A photograph, taken at CERN in 1986 in a piece of apparatus known as a streamer chamber, showing 220 charged subatomic particles bursting out when a high-energy oxygen nucleus collides with a nucleus in a lead target. (credit 11.4)
For most of us it is a world that surpasses understanding. To read even an elementary guide to particle physics nowadays you must find your way through lexical thickets such as this: “The charged pion and antipion decay respectively into a muon plus antineutrino and an antimuon plus neutrino with an average lifetime of 2.603 × 10−8 seconds, the neutral pion decays into two photons with an average lifetime of about 0.8 × 10−16 seconds, and the muon and antimuon decay respectively into…” And so it runs on—and this from a book for the general reader by one of the (normally) most lucid of interpreters, Steven Weinberg.
Construction work in 1975 on CERN’s Super-Proton-Synchroton accelerator, running for seven kilometres in a circle under French and Swiss countryside. (credit 11.5)