Because its a nuclear bomb, it can kill millions of people in a matter of minutes.
Because the USSR had nuclear bombs that they were threatening to use on the Americans.
Lots of people died. Japan surrendered to the Allied forces shortly thereafter. The world entered the nuclear age, and the fear of nuclear war became widespread. And many other things.
A nuclear arms race combined with fear and suspicion could lead to a disastrous nuclear war.
The U.S. began work on making nuclear bombs (atomic bombs) in WW2 out of fear that Nazi Germany might be working on them and use them to win the war, we needed to 1) determine if they could be made and 2) if they could try to make them before Nazi Germany did. After WW2 the U.S. continued making them and began work on hydrogen bombs out of fear that the USSR might attack the U.S. and/or western Europe.
Officially no, nobody sells them. You would have to make your own. But even the needed fissile material is not sold! However, that said there might be a secret black market selling either the material or finished bombs. That is part of the fear of North Korea (already known to have tested bombs) or Iran developing nuclear bombs, that they would sell them.
The Hydrogen bomb was a major fear that people in postwar America had about the use of nuclear weapons.
fear returned because in the war everyone had to be brave because the fear of being killed or bombs falling and after the war there was no bombs or war goin on so people were free to be scared.
The long term result of the use of the Atomic bomb by the US in WW2, has been building new and larger nuclear weapons/bombs. Despite the advances in nuclear activity, it can clearly be seen that the "fear" of using the mass destruction of nuclear weapons has been that no more nuclear or atomic bombs have ever been used again.
An end result of nuclear war.
Radioactive fallout
Communism in China, Soviet nuclear bombs , and discovery of Soviet agents in the United States created the fear that set the stage for the excesses of McCarthyism.
Communism in China, Soviet nuclear bombs , and discovery of Soviet agents in the United States created the fear that set the stage for the excesses of McCarthyism.