Two of Jupiter's satellites, Europa and Ganymede, pull Io into an elliptical orbit around Jupiter. Differences in the strength of Jupiter's gravitational pull as the distance between the planet and Io varies causes slight changes in Io's shape. Scientists believe that Io heats up internally when it changes shape.
The Atomic Age, also known as the Atomic Era, is the period of history following the detonation of the first nuclear (atomic) bomb, Trinity, on July 16, 1945 during World War II.
On August 6, 1945, U.S. President Harry Truman informed the world that an atomic weapon had been detonated on the Japanese city of Hiroshima. Nicknamed Little Boy, the bomb with a power of over 20,000 tons of TNT destroyed most of Hiroshima, killing an estimated 130,000 people.