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.
Jules_Kitano/iStock/Getty Images. The first atomic bomb to be used in combat fell on Hiroshima, Japan, on Aug. 6, 1945. Three days later, a similar bomb fell on Nagasaki. In combination, the bombs killed almost 200,000 people immediately, and tens of thousands died later of radiation poisoning and other wounds.