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Such were the circumstances attending the birth of the great relativity theory. But Einstein later nostalgically recalled the Patent Office as “that secular cloister where I hatched my most beautiful ideas.”
    On several occasions he was to suggest to colleagues that the occupation of lighthouse keeper would be a suitable position for a scientist—because the work would be comparatively easy and would allow the contemplation necessary to do scientific research. “For Einstein,” said his collaborator Leopold Infeld, “loneliness, life in a lighthouse, would be most stimulating, would free him from so many of the duties which he hates. In fact it would be for him the ideal life. But nearly every scientist thinks just the opposite. It was the curse of
my
life that for a long time I was not in a scientific atmosphere, that I had no one with whom to talk physics.”
    Einstein also believed that there was something dishonest about making money by teaching physics. He argued that it was far better for a physicist to support himself by some other simple and honest labor, and do physics in his spare time. When making a similar remark many years later in America, Einstein mused that he would have liked to be a plumber, and was promptly awarded honorary membership in the plumbers’ union.
    In 1905 Einstein published four research papers, the product of his spare time at the Swiss Patent Office, in the leading physics journal of the time, the
Annalen der Physik.
The first demonstrated that light has particle as well as wave properties, and explained the previously baffling photoelectric effect in which electrons are emitted by solids when irradiated by light. The second explored the nature of molecules by explaining thestatistical “Brownian motion” of suspended small particles. And the third and fourth introduced the Special Theory of Relativity and for the first time expressed the famous equation, E = mc 2 , which is so widely quoted and so rarely understood.
    The equation expresses the convertibility of matter into energy, and vice versa. It extends the law of the conservation of energy into a law of conservation of energy and mass, stating that energy and mass can be neither created nor destroyed—although one form of energy or matter can be converted into another form. In the equation, E stands for the energy equivalent of the mass m. The amount of energy that could, under ideal circumstances, be extracted from a mass m is mc 2 , where c is the velocity of light = 30 billion centimeters per second. (The velocity of light is always written as lower-case c, never as upper-case.) If we measure m in grams and c in centimeters per second, E is measured in a unit of energy called ergs. The complete conversion of one gram of mass into energy thus releases 1 × (3 × 10 10 ) 2 = 9 × 10 20 ergs, which is the equivalent of the explosion of roughly a thousand tons of TNT. Thus enormous energy resources are contained in tiny amounts of matter, if only we knew how to extract the energy. Nuclear weapons and nuclear power plants are common terrestrial examples of our halting and ethically ambiguous efforts to extract the energy that Einstein showed was present in all of matter. A thermonuclear weapon, a hydrogen bomb, is a device of terrifying power—but even it is capable of extracting less than one percent of mc 2 from a mass m of hydrogen.
    Einstein’s four papers published in 1905 would have been an impressive output for the full-time research work of a physicist over a lifetime; for the spare-time work of a twenty-six-year-old Swiss patent clerk in a single year it is nothing short of astonishing. Many historians of science have called 1905 the
Annus Mirabilis
, the miracle year. There had been, with uncanny resemblances, only one previous such year in the history of physics—1666, when Isaac Newton, aged twenty-four,in enforced rural isolation (because of an epidemic of bubonic plague) produced an explanation for the spectral