The period in Terragen Old Earth history initiated by the discovery of radiation and atomic structure, and later, by nuclear weapons and atomic energy as a military, political, and industrial factor. More or less equivalent to the the early and middle 1st century BT to early 1st century AT (20th century of Old Earth dating).
Isolated Colonies which have regressed to low techniology status sometimes enter an independent atomic age, deriving power from fissile elements in the planet's crust. On a few occasions the use of fissile elements has led to atomic warfare.
Atomic Age, Early - Text by M. Alan Kazlev The period from the scientific discovery of the atom to the invention of the nuclear bomb.