Rewriting the “laws” of physics, enabling radical new visions of the universe, and pointing toward new sources of energy and mass destruction
Albert Einstein
(1879–1955)
Some years in history stand out for just about everybody: 1066 saw the Battle of Hastings, which brought the Norman Conquest of England. In “fourteen hundred and ninety-two, Columbus sailed the ocean blue”—and “discovered” America. The year 1945 marked the end of World War II. And then there is 1905. The year probably appears on few popular lists of historical standouts, but physicists call it the Annus Mirabilis, the “Miraculous Year.” It was the year that Albert Einstein, a twenty-six-year-old assistant patent examiner working at the Swiss Patent Office in Bern, published four articles in the internationally prestigious Annalen der Physik (Annals of Physics) scientific journal. That publication record alone would make a Miraculous Year for any aspiring scientist. But these particular four articles were far more than personal triumphs. They transformed classical physics into modern physics and thereby disrupted humankind’s vision of reality.
To a non-scientist, the titles of the four papers do not seem like breakthroughs. In fact, they may be barely comprehensible. The first paper, published on June 9, 1905, was “On a Heuristic Viewpoint Concerning the Production and Transformation of Light.” It focused on the “photoelectric effect,” the emission of electrons when light shines on a material. Einstein did not discover this effect, but he addressed a bewildering disconnect between theory and observation and, in so doing, began the disruption of classical physics into quantum mechanics.
Classical physics theory said that changing the intensity of light falling on a material would induce changes in the kinetic energy of the electrons emitted from that material. Moreover, exposing a material to a sufficiently dim light would create a time lag between the initial shining of the light and the emission of an electron. That was the theory, and it made good common sense. Observation, however, revealed something very different—which fit neither the theory nor common sense. Observation revealed that electrons are emitted only when the light reaches or exceeds a certain threshold frequency (energy). Below this threshold, no electrons are emitted, regardless of the intensity of the light. Einstein resolved the disconnect between theory and observation by postulating that energy is exchanged not in continuous amounts, but in discrete packets. Discrete wave packets of light—called photons—released a discrete packet of energy, called a quantum. Classical physics theorized that energy is exchanged in continuous amounts. Based on the photoelectric effect, Einstein postulated that energy is exchanged only in packets, or quanta. In 1921, Einstein received the Nobel Prize for what the prize citation called the “law of the photoelectric effect,” which laid the foundation for quantum mechanics, the basis for today’s physics.
The second 1905 paper, published on July 18, was “On the Motion of Small Particles Suspended in a Stationary Liquid, as Required by the Molecular Kinetic Theory of Heat.” It was based on Einstein’s interpretation of Brownian motion, the microscopic observation made by botanist Robert Brown in 1827 that particles trapped in cavities within pollen grains moved through water—for no apparent reason. What made them move? In his paper, Einstein explained that the pollen was moved by individual water molecules. Stunningly, this explanation was the first empirical evidence of the existence of molecules and, therefore, also the first empirical evidence of the existence of atoms.
On September 26, 1905, Einstein’s “On the Electrodynamics of Moving Bodies” laid the foundation for his most famous equation and the theory that accompanied it, the Special Theory of Relativity. The September 26 paper reconciled with the classical laws of mechanics the equations that the great British physicist James Clerk Maxwell (1831–1879) had created for electricity and mechanics. Einstein did this by introducing major changes to those laws at speeds close to that of light. Einstein showed that the laws of physics are identical in all non-accelerating frames of reference and that the speed of light is the same for all observers, regardless of the motion of the light source. Motion is relative to a frame of reference, except when it is near or at the speed of light. At or near light speed, the differences between Maxwell’s equations for electricity and mechanics, which conflict with the classical laws of mechanics below light speed, are reconciled. This showed that Newton’s laws of motion, basic to classical physics, do not apply as one approaches light speed.
The September 26 paper prepared the way for the paper Einstein published on November 21, the title of which asked the question “Does the Inertia of a Body Depend Upon Its Energy Content?” The answer was the principle of mass-energy equivalence, which is, as Einstein stated in the most famous equation of the modern world, E = mc2, anything with mass has an equivalent amount of energy—and vice versa. Energy (E) may be calculated as mass (m) multiplied by the speed of light squared (c2). Conversely, anything that has energy has a corresponding mass (m) given by its energy (E) divided by the speed of light squared (c2). Mass and energy are equivalent.
All of the Annus Mirabilis papers are foundational to modern physics. This means that they are basic to the modern understanding of the universe, to how we understand reality. What is more, each of the 1905 papers profoundly disrupted our previous understanding. In a practical, existential sense, the mathematical proof of mass-energy equivalence can be seen as the seed from which atomic energy—energy released by nuclear fission, the splitting apart of particles forming the nucleus of an atom—was explored and exploited, both as a source of energy for such things as the propulsion of ships and the generation of electricity, and as the heart of nuclear and thermonuclear weapons capable of destroying all life on earth.
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The Annus Mirabilis papers were just four of the more than 300 scientific papers Einstein published in his intensely creative lifetime. This most productive and celebrated of twentieth-century scientists was born in Ulm, in Württemberg, Germany, on March 14, 1879. His father, Hermann, was a salesman and engineer, and his mother, Pauline Koch, was a homemaker. The family moved to Munich six weeks after Albert was born, and it was here that Hermann and his brother Jacob founded a company that made electrical equipment. Although the Einsteins were Jews, they were non-observant, and Albert was enrolled in a Catholic elementary school from ages five to eight, when he entered the Luitpold Gymnasium, which is now named for him.
The products the Einstein company manufactured were designed to work with direct current (DC) electrical systems. By 1894, when the company made a make-or-break bid on supplying electric street and outdoor lighting for all of Munich, the city, like many others worldwide at this time, had chosen to electrify with the more innovative and efficient alternating current (AC) system. The Einstein brothers could not raise sufficient capital to convert their own factory to make products compatible with AC, lost the bid, and were forced to shutter and sell their factory. Einstein’s parents moved to Italy to start anew, leaving Albert in Munich to finish his gymnasium studies. He rebelled against the strict rote-learning regimen there and, in December 1894, feigned illness and left school to join his parents in Pavia. While waiting to take examinations required to enroll in the Swiss Federal Polytechnic Institute in Zurich, he wrote his first scientific paper, “On the Investigation of the State of the Ether in a Magnetic Field.” He was sixteen.
Although young Einstein failed the general examination, he excelled in mathematics and physics, which prompted the Polytechnic’s sympathetic principal to recommend that he enroll in the Argovian cantonal school in Aarau, Switzerland, address his knowledge gaps there, and then reapply to the Institute. He did well in Aarau, adroitly renounced his German citizenship to avoid compulsory service in the Kaiser’s army, and, at seventeen, was admitted to the Polytechnic. Here he met his future first wife, Mileva Marić—who may (although no evidence has ever been found) have contributed to his Annus Mirabilis papers.
In 1901, Einstein graduated from the Polytechnic Institute certified as a teacher in physics and mathematics. That year, he also received Swiss citizenship. Despite his credentials, he was unable to find a teaching position. He went to work instead as “technical assistant” in the Swiss Patent Office while also attending the University of Zurich, from which he received his doctorate during that Miraculous Year of 1905. Between 1908 and 1913 he held professorships at universities in Bern, Zurich, and Prague. In 1914, he once again took out German citizenship and moved to Berlin, taking a position at the University of Berlin, and lived in that city until 1933.
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The disruptive impact and breadth of his theoretical work, together with the clarity of his expression and his irrepressible personal charm and charisma, not only provoked and electrified the rarefied world of advanced physics, but made Albert Einstein the most famous scientist in the world by the early 1930s. His name became a household word, and he was widely sought as a lecturer and visiting professor. In 1930–1931, he traveled to the United States as a research fellow at the California Institute of Technology. On both the Pacific and Atlantic coasts, he was fêted as a celebrity. New York’s colorful mayor Jimmy Walker presented him with a key to the city, and the president of Columbia University hailed him as “the ruling monarch of the mind.”
Einstein returned to Germany just as the rise of Hitler and the Nazi regime made it increasingly clear to him that life in his homeland would soon be impossible for any Jew. He embarked on another trip to the United States at the start of 1933 for his third two-month visiting professorship at Caltech. He and his second wife, Elsa, set off on a return to Europe in March. During their voyage from America, they learned that their summer cottage had been raided by the Nazis. They were told that, among other things, their small personal sailboat had been confiscated for use at a Hitler Youth camp.
When the Einsteins landed at Antwerp, Belgium, on March 28, they went directly to the local consulate, surrendered their passports, and renounced their German citizenship. They rented a house in Belgium, where they lived before accepting the invitation of Commander Oliver Locker-Lampson of the British Royal Navy, to come to England and live in his cottage outside London. Concerned that German agents might abduct or kill the great scientist, Locker-Lampson provided armed guards to protect the cottage and its inhabitants. He also attempted to secure a Parliamentary act granting the Einsteins British citizenship. When this effort failed, the Einsteins left for the United States, where he accepted a position as resident scholar at Princeton University’s Institute for Advanced Study—a place already well known as a haven for scientists (many of them Jews) in flight from Nazi Germany. Einstein became a U.S. citizen in 1940.
On the eve of World War II in August 1939, the Jewish Hungarian refugee physicist Leó Szilárd asked Einstein to endorse a letter to President Franklin Roosevelt warning him about German experimentation in the field of atomic weapons and urging the United States to begin its own research program. Although Szilárd had originated the letter, he recognized that no scientist was held in higher esteem in the United States than Einstein. He was less interested in taking credit for the letter than in having it read and acted upon. He was right. FDR read the “Einstein letter” and immediately authorized what became in 1942 the Manhattan Project, the vast secret program that created the two atomic bombs dropped on Hiroshima and Nagasaki in 1945.
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After World War II, Einstein turned away from physics—except for work on formulating a unified field theory, a single grand theory intended to explain all of physics—and became increasingly active in the World Government Movement. In the U.S., he was a passionate supporter of civil rights, joining the NAACP and pronouncing racism the “worst disease” afflicting the U.S. When the African American scholar and civil rights activist W.E.B. Du Bois was tried in 1951 for failing to register as a foreign agent when he accepted the chairmanship of the Peace Information Center (which had some affiliation with foreign nationals), the trial judge summarily dismissed all charges when Du Bois’s attorney informed him that Einstein had offered himself as a character witness. That was the scientist’s social authority.
Einstein was long active in Zionist causes and had been instrumental in establishing the Hebrew University in Jerusalem in 1925. In 1952, he was invited to become president of Israel, but declined with an expression of gratitude and humility. An avid amateur violinist, Einstein occasionally played with the likes of the Zoellner and Juilliard string quartets. Although he was a critic of capitalism and inclined toward socialism, he reserved his political advocacy for the so-called global-government movement, which advocated a central governing body for the world’s nations. He was convinced that nuclear weaponry, in the creation of which his own work had played a part, posed a grave danger to humankind that only a global government could mitigate.
At the time of his death—on April 18, 1955, caused by the rupture of an abdominal aortic aneurysm—Einstein had left unfinished the search he had begun after working on his General Theory of Relativity. He was groping toward what he called a “unified field theory,” a way to generalize his geometric theory of gravitation to encompass electromagnetism, thereby creating a unified theory to explain all the fundamental forces of the universe. It is this quest—to unify with gravitation the principal laws of physics—that drives much of modern physics today.