Diary of Albert Einstein
September 8th, 1907
Today I submitted my fifth paper to Annalen der Physik, the scientific journal. I’m still in Bern, Germany. This paper was only three pages long but it explains my thoughts about relativity. Also how mass and energy behave at high speeds. Scientists thought that energy were separate characteristics of objects. Scientific theories and laws had been created to describe each one. But I think that mass and energy are related. I discovered that all mass had great energy. I created a formula to measure the amount of energy in a body: E=mc2. The letter E represents energy. M represents mass. The c2 stands for the square of the speed of light. This theory and the equation became the part of the foundation of the study of physics. This year is my miracle year because I submitted five papers on relativity. After that, I received few letters from scientists asking me to clarify some points in my theories. I was happy because my work wasn’t being ignored.
November 9th, 1939
World War II has began in Europe, several months after Kristallnacht, with the German invasion of Poland. I don’t know if pacifism was effective or not. I’m worried that the pacifist views of others in Europe will create the opportunity for Hitler to gain power. I need to do something about this. I can’t just leave my friends, family and other Jews in Germany while I’m here safe in New Jersey. I decided to write a letter to President Roosevelt. the president of the United States. It reads, in part:
It may become possible to set up a nuclear chain reaction in a large mass of uranium, by which vast amounts of power and large quantities of new radium-like elements would be generated. Now it appears almost certain that this could be achieved in the immediate future.
This new phenomenon would also lead to the construction of bombs, and it is conceivable though much less certain that extremely powerful bombs of a new type may thus be constructed. A single bomb of this type, carried by boat and exploded in a port, might very well destroy the whole port together with some of the surrounding territory. In view of this situation you may think it desirable to have some permanent contact maintained between the Administration and the group of physicists working on chain reactions in America…
Yours very truly,
Albert Einstein
Later President Roosevelt wrote a thank-you letter to me. He created a committee that launched a secret project to develop the atomic bomb. The project was known as the Manhattan Project. The project was eventually successful in creating the world’s first atomic bombs.