The bomb was not made in 1939. It was made in 1945 at the end of WW2. Oppenheimer did not make the bomb, a very large group of scientists and technicians made the bomb. Oppenheimer was the civilian head of the group. That is analogous to saying that a single person invented the rocket that took men to the moon.
To quote Oppenheimer in his farewell speech to the Association of Los Alamos Scientists:
"It may be helpful to think a little of what people said and felt of their motives in coming into this job ... There was in the first place the great concern that our enemy might develop these weapons before we did, and the feeling ... that without atomic weapons it might be very difficult, it might be an impossible, it might be an incredibly long thing to win the war ... Some people, I think, were motivated by curiosity, and rightly so; and some by a sense of adventure, and rightly so. Others had more political arguments ... And there was finally, and I think rightly, the feeling that there was probably no place in the world where the development of atomic weapons would have a better chance of leading to a reasonable solution, and a smaller chance of leading to disaster, than within the United States. I believe all these things that people said are true, and I think I said them all myself at one time or another."
that was not necessary, he already wanted to help. however without general groves assistance he might never have even been on the project, his brother and wife were registered communists and he had participated in communist activities in the 1930s. neither the FBI nor army intelligence trusted him and neither wanted to grant him the clearance needed to work on the project. groves overrode them both and ordered them to grant the clearance.
That's easy. He didn't.
worked on the development of the atomic bomb
During WW 2, J. Robert Oppenheimer was appointed as technical director of the Manhattan Project. Under his guidance, the creation of the first atomic bomb occurred.
Robert Oppenheimer was the chief scientist of the US development of atomic weapons. Thousands of people worked on the bomb in various capacities
he was afraid about killing so many people
Simply he was a main contributor to the atomic bomb.
The scientist given the most credit for the building of the atomic bomb is Robert Oppenheimer.
Robert Oppenheimer's big discovery was the atomic bomb
Robert Oppenheimer.
The first atomic bomb
Robert Oppenheimer.
The atomic bomb that destroyed Nagasaki and Hiroshima, Japan.
they invented the atomic bomb
Robert Oppenheimer
worked on the development of the atomic bomb
Robert Oppenheimer and his team of scientists.
During WW 2, J. Robert Oppenheimer was appointed as technical director of the Manhattan Project. Under his guidance, the creation of the first atomic bomb occurred.
Robert Oppenheimer was the chief scientist of the US development of atomic weapons. Thousands of people worked on the bomb in various capacities