Io is slightly larger than the Moon. It has a mean radius of 1,821.3 km (1,131.7 mi) (about 5% greater than the Moon's) and a mass of 8.9319 Ã 10 kg (about 21% greater than the Moon's).
Leo Szilard invented the atomic bomb and reactor in 1933 as a more efficient method of transmuting elements. It took another 12 years plus a $2,000,000,000 investment by the US to build the first bombs. A patent for an atomic bomb was awarde â¦ d to Leo Szilard in 1934. That patent is regarded as the invention of the atomic bomb.   He immediately tried to turn the patent over to the British government as a gift.
All nuclear weapons require a nuclear fission reaction to work, but pure fission bombs, those that use a fission reaction alone, are known as atomic, or atom, bombs. Atom bombs were first tested in New Mexico in 1945, during the height of World War II.