no, but they were involved as couriers to leak information on the bomb to the USSR.
The Rosenbergs were involved in the Manhattan Project which designed and made the first atomic bomb. They spied for the Soviet Union and passed the information to the Soviet Union on how to make an atomic bomb. They were caught and were executed for spying. With the breakup of the Soviet Union, the great value of their spying to the Soviet Atomic Bomb program was revealed.
I suggest reading Richard Rhodes book: The Making of the Atomic Bomb.
Yes
Everyone thinks it was the Rosenbergs, but it was actually Ted Hall.
The Making of the Atomic Bomb has 886 pages.
The ISBN of The Making of the Atomic Bomb is 0-671-44133-7.
None of the men involved with making "the bomb" were happy about it. They, more than any other living human being knew what doors they had opened (the atomic age).
In September 1949, the first Russian bomb created a changed situation.
I suggest Richard Rhodes book The Making of the Atomic Bomb.
Politians where delighted for the most part and most scientists were too until the scientists developped the bomb and then they begged the politicians not to use it.
many countries
Try reading Richard Rhodes book The Making of the Atomic Bomb.