Albert Einstein Einstein did not return to Germany. He settled in the United States and became an American citizen in 1940. On the eve of World War II, he endorsed a letter to President Franklin D. Roosevelt alerting him to the potential development of "extremely powerful bombs of a new type" and recommending that the US begin similar research. This eventually led to the Manhattan Project. Einstein supported the Allies, but he generally denounced the idea of using nuclear fission as a weapon. He signed the Russell–Einstein Manifesto with British philosopher Bertrand Russell, which highlighted the danger of nuclear weapons. He was
Hans Albert Einstein Hans Albert Einstein Hans Albert Einstein ( ; May 14, 1904 – July 26, 1973) was a Swiss-American engineer and educator, the second child and first son of Albert Einstein and Mileva Marić. Hans A. Einstein was a professor of Hydraulic Engineering at the University of California, Berkeley, and was recognized for his research on sediment transport. His papers are held at the Water Resources Collections and Archives in the University of California, Riverside Libraries and in the University of Iowa Libraries Special Collections and Archives. Hans Albert Einstein was born on May 14, 1904 in Bern, Switzerland, where his