by P. D. Smith
Clearly, the knowledge that a small quantity of matter contains a vast amount of energy enters popular fiction long before the atomic nucleus was split. Atomic energy was beguiling readers and writers with the dream of unlimited power before most scientists would even consider the idea. ‘If we could control this force and handle it on a large scale,’ says Hooker, bursting with excitement, ‘we could do anything with it – destroy the world, drive a car against gravity off into space, shift the axis of the earth perhaps!’18
Like the Roman god Janus, science has two faces. In 1915, while Fritz Haber and his team of chemists at the Institute for Physical Chemistry and Electrochemistry in Dahlem were developing the poison gases that they hoped would win the war for Germany, in the same building a 36-year-old theoretical physicist was trying to glimpse the mind of God.
Albert Einstein’s office was temporary. He had been lured from Zurich to Berlin in 1914 by Germany’s leading physicist, Max Planck, and the chemist Walther Nernst. They had offered him membership of the prestigious Prussian Academy of Sciences and a research professorship at the University of Berlin. The salary was extremely generous, and he was not even expected to teach. In addition they promised him his own institute of physics. But the war had delayed its construction and now it would not open until 1917. In the same month that Haber watched chlorine gas drift over the French trenches at Ypres, Einstein told a friend that wartime Berlin felt like a ‘madhouse’.19 The war had driven Germany insane. Technological progress, said a gloomy Einstein, was ‘like an axe in the hand of a pathological criminal’.20
In October that year he blamed ‘the aggressive characteristics of the male creature’ for war.21 He had a point. Five months earlier, Clara Haber had committed suicide in the Institute’s grounds, some said as a protest at her husband’s war work. Rather than turn their skills to inventing weapons, the atomic scientists Marie Curie and Lise Meitner trained as radiologists in order to be able to X-ray wounded soldiers. Later, Meitner was part of the Dahlem team that first split the uranium atom. Although she had been forced into exile from Germany in 1938, she refused to help build the atomic bomb.
Einstein wasn’t alone in feeling that Berlin had become a madhouse. The Dadaists agreed with the revolutionary physicist. Richard Huelsenbeck and Hugo Ball were starting to give their anarchic performances in the nightclubs of Berlin, before fleeing to Zurich to publicly found the movement.22 In November, an inmate of the asylum that was Berlin presented four scientific papers to the Prussian Academy of Sciences. The theory Einstein set out over four winter evenings was so revolutionary that his opponents branded him a scientific Dadaist.
The general theory of relativity was the culmination of a scientific journey that had begun when Einstein was 17 with a thought experiment about riding on a wave of light. That was in 1896, the year Röntgen’s X-rays made headline news. He didn’t put his ideas on paper until 1905, Einstein’s annus mirabilis. In this single year, he wrote five astonishingly original scientific papers. The first was, he told a friend, ‘very revolutionary’.23 It proposed an alternative theory of light: that it consists of a stream of particles, now called photons, each of which carried a tiny amount, or quantum, of energy. From this interpretation of the nature of light would flow astonishing discoveries about the subatomic realm. They formed the basis of quantum theory, which proved to be a particularly troublesome child for its father.
In another of his 1905 papers, Einstein proposed a novel way of determining the size of atoms, at a time when some leading scientific figures still doubted their very existence. His third paper was a study of the erratic movement of molecules, known as Brownian motion. But it was the paper that he completed in June 1905, ‘On the Electrodynamics of Moving Bodies’, that would transform the way we look at the cosmos. It is better known today as the theory of special relativity. In it Einstein rewrote the rules governing how we perceive the universe around us and overturned many of our common-sense notions about time and space. In particular, he established that the speed of light always remains constant at 186,000 miles per second. All electromagnetic radiation, from X-rays to radio waves, travels at this speed. Nothing can go faster.
One of the implications of this revolutionary idea is that our understanding of time has changed. Einstein realized that if he were able to travel at the speed of light, as he had imagined in his thought experiment, time itself would cease for him. In the relativistic universe there is no single clock keeping time throughout the vast reaches of space. Furthermore, because light takes time to travel, there is always a time lag in communicating information. ‘Time cannot be absolutely defined,’ Einstein told a friend in 1905. When you look up at the stars in the night sky, you see starlight that has taken many years to travel through space at the fastest speed in the universe – the speed of light.
According to Einstein, there is no longer any universal ‘now’, no simultaneity of experience between observers in different parts of the galaxy. The universal time of Newton, in which events happened at the same moment throughout space, has been shattered into fragments of local time.
Einstein’s theory changed space, too. If you did manage to travel at near light speed, you would see clocks in the world you left behind running more slowly, and space contracting – any ruler you happened to pass would shrink in length. But as your speed increased, so too would your mass. That’s something particle physicists at CERN (the European Organization for Nuclear Research) see every day – the more energy they pump into a particle to make it go faster, the more massive it gets. This shows that energy and mass are part of the same equation. In fact, space, time and mass are all relative properties: they are not fixed, but change with velocity. Although he was no Dadaist, Einstein’s universe was certainly bizarre.
Having completed his paper on relativity, Einstein kvetched to a friend that ‘the value of my time does not weigh heavily these days; there aren’t always subjects that are ripe for rumination. At least none that are really exciting.’24 It was an astonishing comment, given the originality of the four papers he had written in the last few months. But one thought did emerge to lighten the tedium of Einstein’s days in 1905:
Namely, the relativity principle, in association with Maxwell’s fundamental equations, requires that the mass be a direct measure of the energy contained in a body; light carries mass with it. A noticeable reduction of mass would have to take place in the case of radium. The consideration is amusing and seductive; but for all I know, God Almighty might be laughing at the whole matter and might have been leading me around by the nose.25
God was not teasing. Einstein wrote up his insight in a three-page paper called ‘Does the Inertia of a Body Depend on Its Energy Content?’ In it Einstein tentatively suggested that ‘if a body emits the energy L in the form of radiation, its mass decreases by L/V2’. As in his paper on relativity, L denoted energy (lebendige Kraft or ‘vital energy’) and V was the speed (velocity) of light. His far-reaching conclusion was that ‘the mass of a body is a measure of its energy content’.26 In 1907 he would express this relationship in the form we know it today: energy (E) released in the form of light (c) results in a reduction in mass (m) by an amount E/c2. The equation was E = mc2.
The light emitted by the vial of radium held up by Pierre Curie that evening in Paris in 1903 revealed a very gradual decrease in mass. As Benjamin Hooker in The Man Who Rocked the Earth pointed out, the amounts involved were minute. But when these tiny amounts of matter are multiplied by the speed of light squared, the release of energy is enormous – almost enough to rock the earth. On 6 August 1945, only a small amount of the uranium-235 in the atomic bomb dropped on Hiroshima, less than two pounds, fissioned and was transformed into pure energy. Its explosive power was equivalent to more than 12,000 tons of high explosive. As Einstein realized in 1905, matter was frozen energy. Or as Frederick Soddy had said two years earlier, the earth was a storehouse stuffed with explosive.27
In 1907, Einstein was still working in the me
dieval Swiss town of Berne as a relatively unimportant patent officer, or as Einstein himself put it in his inimitable style, as a ‘respectable Federal ink pisser’.28 He worked a forty-eight-hour week at the patent office. But just occasionally he pushed his work aside, opened a special drawer in his desk and took out his own research. With characteristic irony, the scientist who was having trouble finding an academic position named the drawer the ‘Department of Theoretical Physics’.
It was at just such a moment in 1907 that Einstein had what he later called ‘the happiest thought of my life’. Gazing out of the large window in his third-floor office while thinking about relativity, Einstein saw a builder on the red-tiled roof of the building opposite. He was struck by an extraordinary idea: if the man were to fall, he wouldn’t feel his own weight. For a brief moment he would be weightless, free of gravity – at least until he hit the ground. This ‘happy’ thought (the weightlessness, not the builder hitting the ground) led Einstein to the equivalence of gravity and acceleration. From there he was able to extend his special theory of relativity to a general theory, in which gravity was no longer a mysterious force, as Newton had supposed, but an intrinsic part of the structure of spacetime.
It was this revolutionary vision of a new, relativistic universe that Einstein laid before the Prussian Academy of Sciences in the winter of 1915. According to his startling theory, starlight would bend as it passed near massive bodies such as the sun. Einstein explained that matter – planets and stars – causes space itself to curve, producing the effect we call gravity. Just as a person standing in the middle of a trampoline produces a marked dip in the fabric, so mass stretches the fabric of space, pulling everything towards it, even light itself.
Einstein challenged astronomers to test his theory by observing the positions of stars that lay near the sun in the sky, which without special apparatus is possible only during an eclipse. According to Einstein, ‘at such times, these stars ought to appear to be displaced outwards from the sun’.29 He even predicted the degree of displacement. His theory was, said fellow German physicist Max Born, ‘a great work of art’.30 Once he had completed it, Einstein didn’t exactly cry Eureka!, but he did confess to being ‘beside myself with joy and excitement for days’.31
The first British scientist to hear about Einstein’s general theory of relativity was the young physicist James Chadwick. He was spending the war interned at a former racecourse just outside Berlin, despite the best efforts of Einstein’s colleagues to have him released. Even under lock and key, Chadwick managed to continue his research into the atom by obtaining a brand of German toothpaste that contained radioactive thorium. Seventeen years later, in 1932, it would be Chadwick who discovered the particle that would unlock the energy inside matter predicted by Einstein’s equation E = mc2. The mysterious glow of radium had illuminated the pathway to the heart of the atom.
Fritz Haber and Albert Einstein didn’t quite see eye to eye. Although he respected Haber as a scientist, Einstein once admitted to Max Born that he considered the Nobel prizewinning chemist to be a ‘raving barbarian’.32 For one thing, Haber couldn’t stomach Swabian food. The discoverer of relativity loved the simple country cooking of his home town, Ulm, in the southern German region of Swabia. Einstein’s second wife, Elsa, his cousin whom he married in 1919, came from the same region and encouraged his taste for their local dishes such as Spätzli, the soft egg noodle that is a staple ingredient in Swabian cooking. Haber was known to refer to Spätzli as ‘mush’.33
Albert Einstein with Fritz Haber at the Kaiser Wilhelm Institute for Physical Chemistry and Electrochemistry, 1914.
Apart from food, the war was another bone of contention between the two men. Einstein was elated when the war ended, despite the fact that his homeland had been defeated.34 On 9 November 1918, the man who had pinned a medal to Röntgen’s chest for discovering X-rays was suddenly out of a job – Kaiser Wilhelm II was forced to abdicate and a republic was proclaimed. That same day, Einstein’s lecture on relativity was cancelled – ‘due to revolution’, as he wrote in his course notes.35 Whereas the physicist Arnold Sommerfeld expressed his dismay at ‘everything unspeakably miserable and stupid’ at this time,36 Einstein was overjoyed. He was optimistic that his country now had a democratic future: ‘Germans who love culture will soon again be able to be as proud of their fatherland as ever – and with more justification than before 1914’.37
In contrast, the inventor of chemical weapons wept at the defeat of Germany. Fritz Haber’s daughter recalls how, after the Kaiser’s abdication, she and her father attended a performance of Friedrich von Schiller’s play about France’s tragic saviour, Joan of Arc, Die Jungfrau von Orleans. She was shocked to see tears streaming down his face.38 Haber took defeat personally: his superweapon had failed to win the war and save the Fatherland. It wasn’t just Germany that had lost, but science too.
Haber was not alone in his bitterness. After the war, the groundless rumour spread that the German military had been stabbed in the back by spineless politicians. It was a dangerous myth, and it fuelled nationalist resentment in the coming years. When the German republic was proclaimed and the armistice signed in November 1918, a 29 year-old German corporal was recovering in hospital fifty miles north of Berlin after being half-blinded by mustard gas. Adolf Hitler was appalled when he heard news of the armistice:
Everything went black before my eyes. I tottered and groped my way back to the dormitory, threw myself on my bunk and dug my burning head into my blanket and pillow… So it had all been in vain. In vain all the sacrifices… in vain the death of two millions… There followed terrible days and even worse nights… In these nights hatred grew in me, hatred for those responsible for this deed. In the days that followed, my own fate became known to me… I, for my part, decided to go into politics.39
For his invention of poison gas, Fritz Haber was placed on an Allied list of war criminals. He grew a beard to avoid being recognized on the street and even went to Switzerland to evade arrest. But after a few months the threat was removed, and by 1919 he was back in charge of his Institute. That year he was awarded the Nobel Prize in Chemistry. The press on both sides of the Atlantic was outraged. But in his desire to use science to end the war, Haber could claim to be a scientist who walked in the footsteps of Alfred Nobel.
Military men on all sides now accepted that scientific weapons of mass destruction, such as poison gas, were a part of modern warfare. In Britain, the official Holland Report on chemical warfare concluded without hesitation in 1919 that gas was a ‘legitimate weapon in war’. The Committee that drew up the report assumed that it was a ‘foregone conclusion’ that gas would be used in the future, ‘for history shows that in no case has a weapon which has proved successful in war ever been abandoned by Nations fighting for existence’.40
At the war’s end, Germany was on its knees. It had lost 1,773,000 soldiers killed and more than four million were wounded. The streets of Berlin teemed with returning soldiers, angered and embittered after futile years of bloodshed. At the same time, refugees from the east flocked into the city. All were hungry. Berliners had been forced to endure what physicist Max Born called ‘turnip winters’ during the war.41 Food shortages meant that turnips became the key ersatz ingredient in everything from jam to flour and even beer. But by the end of the war people were dying of starvation. The pinched faces of malnourished children in Käthe Kollwitz’s unforgettable etchings speak powerfully of the suffering of Berliners in these years. To hunger was added a new scourge, disease. As the war ended, an epidemic of Spanish flu swept across Europe, killing three hundred people a day in Berlin.
The city and the land were ripe for revolution. In the final days of the war, sailors waving red flags had mutinied, taking control of the city of Kiel, an act that sparked revolution throughout Germany. The Russian Bolsheviks had led the way in the previous year. Now workers with red armbands and rifles roamed the streets of Berlin, looting and beating up officials associated with the old re
gime. At one point, Einstein was summoned to save the rector and several university professors from an uncertain fate, when they were taken hostage by radical students. He and Max Born passed through streets ‘full of wild looking and shouting youths with red badges’ on his way to the Reichstag.42 There, Einstein negotiated first with the Students’ Council and finally with the new Chancellor, Friedrich Ebert himself. Einstein’s colleagues regarded him as a ‘high-placed Red’, he told his mother proudly.43 That was why the students trusted him. While the would-be saviour scientist, Fritz Haber, was hiding behind his freshly grown beard, Einstein was being hailed as a man of the people – a popular hero.
This could not be said for most scientists after the war. In contrast to the general pre-war optimism about science and technology, there was now a pervasive doubt about what the future held. Some people argued that it was unfair to criticize scientists for their lethal inventions. As someone wittily observed during World War I, ‘to blame chemistry for the horrors of war is a little like blaming astronomy for nocturnal crime’.44 But German expressionist writer Georg Kaiser had experienced gas warfare at first hand. His play cycle, Gas I and Gas II, written during and after the war, shows how the desire of industry and science for the ultimate energy source could all too easily degenerate into a quest for the ultimate weapon.
One of the great novelists of the Weimar Republic, the Berliner Alfred Döblin, echoed Kaiser’s fears in his futuristic fable Mountains, Oceans and Giants (1924). Set in the twenty-third century, his novel chronicles humankind’s disastrous attempts to control and exploit the forces of nature across five hundred years, from the replacement of natural food with scientific substitutes to the catastrophe brought about when Greenland’s glaciers are melted by harnessing the energy of volcanoes. This Faustian exploit leads to the discovery of a force of nature that gives science ultimate control over matter. But it is a power that this technologically advanced civilization cannot control.