the.com/atomic age

means The historical period, beginning in the mid-20th century, defined by the development of nuclear weapons and nuclear power and the cultural anxieties and optimism that came with them.

from The phrase surged into use after 1945, when the atomic bombings of Hiroshima and Nagasaki showed the world what splitting an atom could do. 'Atomic age' became shorthand across newspapers, advertising, and science fiction for a new era — one promising clean nuclear energy and flying cars in the same breath as it promised mutually assured destruction. The word 'atomic' itself traces back to Greek 'atomos,' meaning 'uncuttable' — ironic, since the whole age was built on humans finally figuring out how to cut it.