Question

which event left Einstein deeply shaken and why​

Answer 1

When Einstein wrote a letter to the American president (Franklin D. Roosevelt) On August 2 1939, in which he warned about the power of atom Bomb.

Previously stated Letter, Albert Einstein to a Japanese pen pal show the physicists to be defensive over atomic bombing of Hiroshima and Nagasaki.

In the top run, the anniversary actually delivers nuclear attacks and prevents that fateful Descion.