The last remaining trove of Albert Einstein's personal family letters is being opened to the public this week. They had been closely held by his stepdaughter Margot Einstein, who decreed that they remain sealed for 20 years after her death. Some of the letters are being published by Princeton University Press in the 10th volume produced by the Einstein Papers Project at Caltech, and they are a revelation. "Einstein's private correspondence refutes the simplistic view of him as an isolated, remote man who immersed himself in his work at the expense of human contact," says general editor Diana Kormos Buchwald. That is nowhere more true than in the tense months between April and December 1915, when his family life was unraveling and he was racing--under brutal competitive pressure--to complete his general theory of relativity.
In 1915, Albert Einstein was struggling to wrest from nature what would turn out to be his crowning achievement, perhaps the most beautiful theory in all of science. Ten years earlier, he had come up with the special theory of relativity, which said that time and space were each relative for observers moving at different constant velocities. Now he was trying to generalize the theory by conceiving of gravity as a curving of the fabric of something he called space-time.
It was an excruciating period. His marriage to Mileva Maric, an intense and brooding Serbian physicist who had helped him with the math of his 1905 paper, had just exploded. She had left him in Berlin and moved to Zurich with their sons Hans Albert, 11, and Eduard, 5. Suffering from acute stomach pains exacerbated by the food shortages of World War I, he was being nursed by a first cousin, Elsa Einstein, whom he would eventually marry.
His letters, including some made public this week, show how his personal and scientific struggles intertwined in 1915, culminating in his great triumph that fall. The tale begins with two letters written in early April by Hans Albert (known as Adu), begging his father to visit him and his brother (known as Tete) in Zurich for spring vacation: Dear Papa, Imagine, Tete can already multiply and divide, and I am doing gometetry (geometry), as Tete says. Mama assigns me problems; we have a little booklet; I could do the same with you then as well. But why haven't you written us anything lately? I just think: "At Easter you're going to be here and we'll have a Papa again." Yours, Adu!