E=mc2 (23 page)

Using material from Lawrence's lab,
EMILIO SEGRÈ
had become the first person
to
create the element technetium. He also managed to stay at the Berkeley Lab long enough to become the codiscoverer of plutonium, the element used in the Nagasaki explosion. At the reduced salary Lawrence gave him, there had been no chance of bribing any consular officials to get his elderly parents out of Italy. His mother was captured during a Nazi manhunt in October 1943, and murdered soon after that; his father, who had been safely hidden in a papal palace, died of natural causes the next year.

When the war was over Segre went to his father's tomb, scattering a small sample of technetium from Lawrence's lab over it: "The radioactivity was minuscule, but its half-life of hundreds of thousands of years will last longer than any other monument I could offer."

As soon as Denmark was liberated,
GEORGE DE HEVESY
went back to the jar of strong acid in which he'd dissolved the Nobel gold medals at Niels Bohr's Copenhagen institute, and simply precipitated them back out. The Nobel foundation then recast them, and they were returned to their rightful owners. When de Hevesy had first dissolved them he'd only just recovered from a full-fledged midlife crisis, convinced that at age fifty he was past the age for fresh invention. The recovery was quite complete, for soon he had a Nobel medal of his own, awarded for work he did—at an age when most physicists' creativity is long gone—on radioactive tracers.

All laureates are offered Swedish citizenship, but de Hevesy was one of the few who took that up, settling in Stockholm for the rest of his long life. In the 1960s, he could sometimes be seen strolling in La Jolla, California, an erect elderly man, happy visiting with his American grandchildren, telling them what he remembered of life growing up in the 1880s in a baronial palace in Hungary.

ERNEST LAWRENCE
came out of the war in triumph, and succeeded in raising more and more funds, and building larger and larger machines, until finally he proposed a cyclotron that violated the special theory of relativity, and so was physically impossible. None of his young men would dare to explain that to him, however, and the failure of his efforts to get it to work ended up wrecking his health. A little before he died, in 1958, he told a group of graduate students at the University of Illinois: "Why, fellows, you don't want a big machine. There's too much emphasis these days on sheer size for its own sake."

Heisenberg never realized he was being recorded at the Cambridgeshire country house.

HEISENBERG:
Microphones installed? [laughing] Oh no, they're not as cute as all that. I don't think they know the real Gestapo methods; they're a hit old-fashioned in that respect.

But when the recordings were released a half century later they proved Heisenberg's cover story false. There was a fine justice in Heisenberg and the others being sequestered there, for it was only a short distance from the other elegant country house that the British secret service kept, where the six Norwegians who destroyed his project had prepared for their mission.

Heisenberg almost hadn't survived to be captured, for the predecessor of the CIA had sent an assassin, the ex-athlete Moe Berg, against him during that final Swiss trip. Berg was planted in the audience of the seminar Heisenberg gave in Zurich. If Heisenberg showed evidence that his bomb project was on the right tracks, he would be killed. Berg had a gun, and understood some undergraduate-level physics, but the talk was too technical for him to follow. His scrawled notes from that meeting still survive in official archives: "As I listen, I am uncertain—see: Heisenberg's uncertainty principle—what to do to H. . . ." He left Heisenberg alone.

The heavy water facility at
VEMORK
continued in operation till the early 1970s, when, having outlived its economic usefulness, it was blown up by Norsk Hydro engineers. Some of the rubble was removed by truck and train, but much was left in place, and simply paved over. Several thousand visitors walk over it each year, for the old generating station behind it has been converted into an excellent museum, and the location of the commando raid is directly under the route to the entrance.

The
I. G. FARBEN
company, which had taken over the plant's operation during the war, was briefly broken up by Allied authorities, after the Nuremberg trials showed its executives profiting from the purchase and subsequent death of human slaves. One of its main constituents, the
BAYER
company, though popularly known just for its aspirin, continued to be a major force in general chemicals worldwide.

The
BERLIN AUER
factories, where female slaves from Sachsenhausen had been worked to death to supply the German project with uranium oxides, almost survived intact till the end of the war. In the last few months, though, they were obliterated by Allied bombers acting on Groves's instructions, in large part to keep them from falling into Russian hands. Almost all the Berlin Auer executives avoided jail sentences, and indeed even before the war ended had been thinking of their future. American investigators found that all Europe's supplies of radioactive thorium had been purchased by an unknown buyer—it was the Berlin Auer company, which planned to use it to make white-glowing toothpaste once more.

War crime trials in Oslo after the war led to the conviction of several guards—both Germans, and Norwegian collaborators— responsible for the deaths of the surrendered
BRITISH AIRBORNE TROOPS
. Many of the troops had been thrown into shallow graves, with their hands tied behind their backs with barbed wire. They were disinterred for reburial; the head of the Norwegian collaborationist government, Vidkun Quisling, was forced to help dig up the remains of other prisoners who'd been killed with them.

The once-secret reactor at
HANFORD, WASHINGTON
, which had played such an important role in creating the plutonium used in the Nagasaki and later bombs, continued as a central site for the production of American nuclear weapons. After several decades of service, though, a changed national mood increasingly saw it as a center of environmental despoliation: cleanup costs for its leaked or inadequately stored radiation were estimated at $30-$50 billion.

CECILIA PAYNE'S
thesis advisor nearly brought her career to a halt by making sure she was kept from any of the new electronic equipment coming in. He also ensured, as director of Harvard's observatory, that when she did
give
courses, they weren't listed in the Harvard or Radcliffe catalog; she even found out, years later, that she had been classified as "equipment expenses" when her salary came due. When the worst of the sexism ended, and a decent director of the observatory took over in the postwar era, it was too late. She had such a heavy teaching load by then that "there was literally no time for research, a setback from which I have never fully recovered."

Instead, she became one of the kindest supporters of the next generation at Radcliffe, always available for long talks to students at loose ends. She also kept intellectually nimble by learning languages, to add to the Latin, Greek, German, French, and Italian she'd been comfortable with when she'd arrived in America. "Icelandic was a minor challenge," her daughter wrote, though "I cannot say she truly mastered it." Cecilia Payne had the pleasure of seeing that daughter become an astronomer—and publishing several papers with her.

The BBC talks and subsequent book were such a success that not only did Hoyle and his wife get enough money to buy their first refrigerator, but it led to a career popularizing science, which he carried on in parallel with his academic research. This allowed him to put enough savings aside that in 1972, when he told Cambridge administrators he would resign if they continued going back on their word about funding for the successful astronomical research center he'd created, he was able to startle them ("Fred won't resign. Nobody resigns a Cambridge Chair"), and politely walk out. He has continued to publish innovative papers, some of them flighty, some of them profoundly sensible—as has been the wont of top scientists from Newton on. If it weren't for the way his Yorkshire honesty irritated the old guard in Britain and the astronomical community generally, it's generally accepted that he would have long since been granted a Nobel Prize for his work on the formation of the elements.

Forty years after his rebuff by Eddington, Chandra finally returned to the study of black holes. There are photographs of brightly dressed young physicists in the clothes of the early 1970s, sitting around a table in the Caltech cafeteria, listening to this perfectly tailored, suited man of the generation of their grandparents. He surpassed almost all of them in his agility with new applications for general relativity, and in 1983, over half a century after the sea voyage, he published one of the fundamental works on the mathematical foundations of black holes. That was the year he won the Nobel Prize, and then—following his usual habit—he shifted directions once again, expanding an elaborate exploration of Shakespeare, and of esthetics generally.

In mid-1999, NASA launched a large satellite for deep space observation, capable of capturing images from the very edge of black holes. The satellite crosses over much of the earth—the Arabian Sea, Cambridge, and Chicago included— in its mission, and it is called the
CHANDRA X-RAY OBSERVATORY.

Although
ERWIN FREUNDLICH
missed out on the 1919 eclipse expedition, his spirits recovered when industrialists in the new Weimar Republic donated large funds to build a great astronomical tower in Potsdam. This would allow further tests of general relativity's predictions, even in periods when there was no eclipse. Zeiss supplied the equipment, and Mendelsohn, the great expressionist architect, designed the building—it's the famous Einstein Tower featured in many books on 1920s German architecture.

Through Einstein's help, Freundlich became the Einstein Tower's scientific director. The measurements he undertook, however, proved to be impossible with the technology of the time. Only in 1960, at Harvard, did another team manage to give this further confirmation of Einstein's work.

Notes

These notes are for people who want to know more. Some are serious: why Tom Stoppard has it all wrong when he uses relativity to try to back moral viewpoints in his plays; what the deep links are between relativity, thermodynamics, and the Talmud; how close Germany really came to getting radioactive weapons. Other notes are lighter, though also significant in their own way: I loved finding out that there are parts of World War I German battleships on the moon; that Maxwell didn't write Maxwell's equations; that Faraday never said, "Well, Prime Minister, someday you can tax it"; and even why Einstein never liked calling his work the theory of relativity.

Preface

"Einstein explained his theory to me every day . . .": Carl Seelig,
Albert Einstein: A Documentary Biography (London:
Staples Press, 1956), pp. 80-81.

George Marshall saw to it . . . : Leslie Groves,
Now It Can Be Told: The Story of the Manhattan Project
(London: Andre Deutsch, 1963), pp. 199-201; Andrew Deutsch; see also Samuel Goudsmit,
Alsos: The Failure in German Science
(London: Sigma Books, 1947), p. 13.

1. Bern Patent Office, 1905

Letter to Professor Wilhelm Ostwald:
Collected Papers of Albert Einstein, Vol. I,
The Early Years: 1879-1902, trans. Anna Beck; consultant Peter Havas (Princeton, N.J.: Princeton University Press, 1987), p. 164. I've added Ostwald's address.

". . . nothing would ever become of you . . .": Ibid., p. xx.

"Your presence in the class . . .": Philipp Frank,
Einstein: His Life and Times,
trans. George Rosen (New York: Knopf, 1947, revised 1953), p. 17.

"displayed some quite good achievements": Albrecht Folsing,
Albert Einstein: A Biography
(London: Viking Penguin, 1997), pp. 115-16.

. . . jokingly called his department of theoretical physics . . . : The phrasing is recalled by a visitor, Rudolf Laden-burg; in Folsing,
Albert Einstein,
p. 222; see also Anton Reiser,
Albert Einstein, a Biographical Portrait
(New York: A. and C. Boni, 1930), p. 68.

"I like him a great deal . . .": Folsing,
Albert Einstein,
p. 73.

. . . feeling "the greatest excitement": Reiser,
Einstein,
p. 70.

"The idea is amusing . . . that I cannot know."
Collected Papers,
vol. 5, doc. 28. The friend was Conrad Habicht.

E=mc
²
had arrived in the world: Einstein did not write E=mc
²
in 1905. In the symbols he was using at the time, the equation would have come out as L=MV
²
. But more important, in 1905 he still only had the notion that when an object sends out energy, it will lose a small amount of mass in the process. The full understanding that the reverse happens only came later.

During World War II, when Einstein wrote out a copy of his main 1905 relativity paper to be auctioned for war bonds, he turned at one point to his secretary, Helen Dukas, as he was taking down her dictation: "Did I say that?" She told him he had. "I could have said it much more simply," he replied. (The story is in Banesh Hoffman,
Einstein, Creator and Rebel
(New York: Viking, 1972), p. 209.

2. E Is for Energy

One of the men who took a central role in changing this . . . : There were other researchers involved in understanding the conservation of energy, but focusing on Faraday gave me a chance to bring in the concept of a field pervading seemingly "empty" space, so central to Einstein's later work. For the other originators and their links, start with Thomas Kuhn's essay and Crosbie Smith's
The Science of Energy,
listed in the Guide to Further Reading for this chapter. Faraday's own views on how thoroughly energy was conserved differed from those of many subsequent researchers; see e.g., Joseph Agassi's
Faraday as Natural Philosopher
(Chicago: University of Chicago Press, 1971).

. . . a lecturer in Copenhagen had now found . . . : The Dane was Hans Christian Oersted, and most physics textbooks say that he "stumbled" across his results. But that's not possible: a compass needle won't be deflected if the compass is at an angle to the electric wire, or if the current in the wire is too low or too high, or if the wire is a low-resistance copper, and so on. In fact Oersted had been hunting for this link between electricity and magnetism for at least eight years. The reason that's so often missed is that his motivation hadn't come from standard scientists, but from Kant, Goethe (of the Elective Affinities), and, especially, Schelling. But Faraday recognized what Oersted had really been up to.

Note that Oersted's success doesn't mean all extrascientific motivations prove successful. An ability to objectively assess what such motivations offer is crucial. Einstein was excellent at this, at least early on in his career: his study of Hume readied him for seeing how arbitrary the woven definitions that physicists used were, and so how far they could someday be stretched; his love of Spinoza was a constant, urgent reminder of the ordered beauty waiting in our universe. Goethe, by contrast, was almost always poor at using philosophy in science, and wasted years on a theory of vision, simply because he was convinced it "should" be true. As the old saying has it, to do mathematics you need paper, a pen, and a wastebasket; to do philosophy, the paper and pen are enough.

"You know me as well or better . . .": The quote is from a letter from Faraday to Sarah Bernard,
The Correspondence of Michael Faraday, vol.
1, ed. Frank A. J. L. James (London: Institute of Electrical Engineering, 1991), p. 199.

From his religious background, he imagined . . . : This is my own interpretation, building on ideas from cognitive anthropology on correlates between social behavior and ideologies. For a more conventional view, see Cantor's
Michael Faraday, Sandemanian and Scientist
in the Guide to Further Reading.

"Why, Prime Minister, someday you can tax it.": It's a catchy story, and pleasing for engineering types, but the phrase has never been found in Faraday's letters, or in the letters of anyone who knew him, or in any newspaper accounts of the time, or in any of the biographies written by individuals who had been close to him. American writers often recount it as having been said to Gladstone, which is less than convincing, as Gladstone became prime minister forty-seven years after Faraday's discovery, at a time when electrical devices were common. The British government had long been aware that its strength had grown with industrial innovation.

"All at once he exclaimed . . .": Silvanus P. Thompson,
Michael Faraday: His Life and Work
(London: Cassell, 1898), p. 51

Faraday's invisible whirling lines . . . : It's the first modern occurrence of the notion of a "field." The reason this came as such a surprise in 1820s Europe was that for over a century, all respectable physicists had "known" that no such thing could exist. The medievals might have believed the heavens were full of goblins and spirits and unseeable, occult forces, but when Newton had shown how gravity could work instantaneously across empty space, without any intervening objects to carry it along, he had been "sweeping cobwebs off the sky."

Yet while others accepted that as given, Faraday researched enough to find that Newton himself had viewed the notion of entirely empty space as just a provisional step. Faraday liked quoting one of Newton's 1693 letters to the astronomically curious young theologian Bentley: ". . . that one body can act upon another at a distance, through a vacuum, without the mediation of anything else . . . is to me so great an absurdity, that I believe no man who has in philosophical matters a competent faculty of thinking can ever fall into it."

Both quotes are from Maxwell's essay "On Action at a Distance," in Volume II
of The Scientific Papers of James Clerk Maxwell, ed.
W. D. Niven. (Cambridge: Cambridge University Press, 1890), pp. 315, 316.

. . .and then Humphry Davy accused him . . . : What actually happened? It's true that Davy and the researcher William Hyde Wollaston had already started work on this topic, but Davy and Wollaston were nowhere near reaching Faraday's great result—and Faraday was not the sort to steal. To get an idea of Davy's hinted accusations, there are Faraday's distraught letters, and Wollaston's curt response, especially the letters of October 8 and November 1,1821, in James, ed.
The Correspondence of Michael Faraday.
A measured discussion is available in
Michael Faraday: A Biography,
by L. Pearce Williams (London: Chapman and Hall, 1965), pp. 152-160.

Faraday never spoke out against Davy: But he was hurt. For years Faraday had been accumulating a scrapbook on Davy: there were geological sketches as a reminder of their travels together, drafts of several of Davy's papers, which Faraday had copied out in full in his own neat hand; friendly letters Davy had sent him in the past; little sketched doodles of events in their life. The scrapbook is arranged chronologically. After September 1821, Faraday never added
to
it again.

Letter of May 28, 1850, from Charles Dickens:
The Selected Correspondence of Michael Faraday,
vol. 2:1849-1866, ed. L. Pearce Williams (Cambridge: Cambridge University Press), p. 583.

But Faraday's vision . . . a satisfactory alternative: In Faraday's time, energy conservation was just an empirical observation. Only in 1919 did Emmy Noether give a deeper explanation of why
it
was so persistently noted. For good introductions to the links between symmetry and conservation laws, see
The Force of Symmetry,
by Vincent Icke (Cambridge: Cambridge University Press, 1995), especially the discussion on p. 114; or Chapter 8
of Fearful Symmetry: The Search for Beauty in Modern Physics,
by A. Zee (Princeton. N.J.: Princeton University Press, 1986).

this quiet school . . . student-centered lines: Einstein had the added advantage of lodging with Jost Winteler, the school's director, who twenty years before had completed an immensely original doctorate on the
Relativitdt der Verhdltnisse, or
the "situational relativity" of surface features in a language, and how those stemmed from deeper, unchanging properties of the language's sound systems. The structural overlaps with Einstein's later work in physics are profound, down even to Einstein's preference for the label Invariant Theory for what he had created— the very term Winteler had used. For background on Winteler's thesis, see pp. 143ff of Roman Jakobson's contribution to
Albert Einstein, Historical and Cultural Perspectives, ed.
Gerald Holton and Yehuda Elkana (Princeton, N.J.: Princeton University Press, 1982); there's also the charming essay "My Favorite Topics" in
On Language: Roman Jakobson, ed.
Linda R. Waugh and Monique Monville-Burston (Cambridge, Mass.: Harvard University Press, 1990), pp. 61-66.

4. m Is for mass

[Lavoisier] . . . was the man who first showed . . . a single connected whole: The word
mass
is in quotes, for Lavoisier's findings were only about the conservation of matter, while in E=mc
²
the "m" stands for inertial
mass.
This is a much more general thing, concerned not with the detailed inner properties of an object, but simply, in the tradition of Galileo and Newton, with its overall resistance to being shifted or pushed. The distinction seems fussy, but is fundamental. Astronauts find themselves weighing less when they're on the moon than they did before leaving the Earth, but that isn't because parts of them have disappeared. In the same way, as we'll see in Chapter 5, if you watch a sufficiently fast rocket, you'll see its mass increase immensely, but that happens without more atoms popping into being in its metal frame, or indeed without the atoms in its body getting pudgy at all.

What makes Lavoisier worth concentrating on is that his work on the conservation of matter ended up boosting interest in the conservation of mass, even though by today's understanding there's no reason for mass and matter to always be linked. In the late 1700s, however, no one cared that what he was "really" showing was the conservation of atoms—for no one in his time had a clear notion that atoms as physical entities existed.

the moment came . . . a truly major experiment: If one asks "Who was the first to show that the conservation of mass is true?" the answer has to be "No one, really." Lavoisier had shown in 1772 that some sort of air joined with metal when it was heated—but that was largely an extension of what de Morveau, Turgot, and others had done before him. In 1774 Lavoisier did carry out more extensive experiments with lead and tin, confirming that what carried the extra weight was air rushing into the heated containers— but this too wasn't entirely original, building on concepts he'd borrowed from the unsuspecting Englishman Priestley. Even the 1775 confirmatory experiments Lavoisier carried out with mercury, ended up being phrased in a way that atomists from Roman times would have taken for granted. Yet Lavoisier did more than grab credit for what others had done. Priestley and the others hadn't fully conceived of a conceptual system that made sense of these various experiments. Lavoisier had.

On the different attitudes brought to bear—as well as the historiographical considerations involved—see Simon Schaffer's accomplished "Measuring Virtue: Eudiometry, Enlightenment and Pneumatic Medicine," in
The Medical Enlightenment of the Eighteenth Century, ed.
A. Cunningham and R. K. French (Cambridge: Cambridge University Press, 1990), pp. 281-318.

"Everybody confirms that M. Lavoisier . . . French capital": Arthur Donovan,
Antoine Lavoisier: Science, Administration, and Revolution
(Oxford: Blackwell, 1993), p. 230.

"I am the anger, the just anger . . .": Louis Gottschalk,
Jean Paul Marat: A Study in Radicalism
(Chicago: University of Chicago Press, 1967).

"Our address is . . . room at the end": Letter from Lavoisier to his wife, November 30,1793 (10 Frimaire, Year II); in Jean-Pierre Poirier,
Lavoisier: Chemist, Biologist, Economist
(College Park, Penn.: University of Pennsylvania Press, 1996), p. 356.