Was atom bomb made on purpose or by an accident?

Answer 1

The atom bomb was definitely made on purpose, and it required much effort to make it work. Splitting the atom is not the type of thing to be done accidentally.

At the beginning of the 20th century, the structure of the atom was believed to be like a "miniature solar system" with negatively-charged Electrons orbiting a positively charged nucleus of unknown structure. In 1919, Ernest Rutherford, a physicist from New Zealand, working in the UK, achieved the first artificial transmutation of an element when he changed several atoms of nitrogen into oxygen. In the process of changing nitrogen into oxygen, Rutherford detected a previously unknown high-energy particle with a positive charge - the Proton. In 1932, James Chadwick, a colleague of Rutherford, identified a further particle, the Neutron, so-named because it had no charge. From 1932 onwards, the atom was seen as comprising a positively charged nucleus, containing both protons and neutrons, circled by negatively charged electrons equal in number to the protons in the nucleus.

Beginning in 1934, the Italian physicist Enrico Fermi began bombarding elements with neutrons, theorizing that Chadwick's uncharged particles could pass into the nucleus without being repelled. Like other scientists at the time, Fermi paid little attention to the possibility that matter might be annihilllated during bombardment and result in the release of huge amounts of energy in accordance with Einstein's formula, E=mc2, which stated that mass and energy were convertible. One element Fermi bombarded with neutrons was uranium, the heaviest of the known elements, producing "new" substancess in the process. Some scientists thought that the resulting substances were new "transuranic" elements, while others noted that the chemical properties of the substances resembled those of lighter elements. For several years, attempts to identify these substances dominated the research agenda in the international scientific community, with the answer coming out of Nazi Germany just before Christmas 1938.

Otto Hahn and Fritz Strassmann were bombarding elements with neutrons in their Berlin laboratory when they made an unexpected discovery. They found that uranium nuclei broke into two roughly equal pieces and became not the new transuranic elements but radioactive barium isotopes and fragments of the uranium itself. The substances Fermi had created didn't just resemble lighter elements - they were lighter elements. The products of the Hahn-Strassmann experiment weighed less than that of the original uranium nucleus. Mass was being converted to energy. Fermi had produced fission in 1934 but had not recognized it.

Fission caused the immediate release of enormous amounts of energy along with the additional emission of more neutrons. Given the right set of circumstances, these new neutrons might collide with other atoms and release more neutrons, in turn smashing into other atoms and, at the same time, continuously emitting energy. The possibility of such a "chain reaction" completely altered the prospects for releasing the energy stored in the nucleus. A controlled self-sustaining reaction could be used to generate a large amount of energy for heat and power, while an unchecked reaction could create an explosion of unbelievable magnitude. The "atomic bomb" became a scientific possibility.

In the US, President Roosevelt responded to the call for government support of uranium research quickly but cautiously. The Advisory Committee on Uranium met for the first time on October 21, 1939. In early 1940 the committee, including both civilian and military representation, recommended that the government fund limited research on Fermi's work on chain reactions at Columbia University. Talks were held with the British government about ways of sabotaging any German efforts to produce nuclear weapons. In May, 1940, the German Army invaded Denmark, the home of Niels Bohr, the world's leading expert on atomic research. To prevent him from being forced to work for Nazi Germany, the British Secret Service arranged his escaped to Sweden before being moving to the United States.

The Manhattan Project was set up in 1942, in the US under the command of Brigadier General Leslie Groves, to produce an allied atomic bomb. Scientists from around the world were brought together at the Los Alamos National Laboratory in New Mexico, including Enrico Fermi (Italy), James Chadwick (Britain), Niels Bohr (Denmark), Robert Oppenheimer (USA), David Bohm (USA), Leo Szilard (Hungary), Eugene Wigner (Hungary), Rudolf Peierls (Germany), Otto Frisch (Germany), Felix Bloch (Switzerland), James Franck (Germany), Emilio Segre (Italy), Klaus Fuchs (Germany) and Edward Teller (Hungary).

A similar project existed in the USSR after September 1941, under Igor Kurchatov (with some of Kurchatov's breakthroughs coming secondhand from "spies" within the Manhattan Project).

It was initially feared that Hitler was very close to developing his own bomb. The efforts undertaken in Germany, headed by Werner Heisenberg, made little progress, though. Many German scientists were said to express surprise to their Allied captors when the bombs were detonated in Japan.