II.

Fission Weapons

In 1905 Albert Einstein published his special theory of relativity. According to this theory, the relation between mass and energy is expressed by the equation E = mc², which states that a given mass (m) is associated with an amount of energy (E) equal to this mass multiplied by the square of the speed of light (c). A very small amount of matter is equivalent to a vast amount of energy. For example, 1 kg (2.2 lb) of matter converted completely into energy would be equivalent to the energy released by exploding 22 megatons of TNT.

In 1938 German chemists Otto Hahn and Fritz Strassmann split the uranium atom into two roughly equal parts by bombardment with neutrons. As a result of these experiments, the Austrian physicist Lise Meitner, with her nephew, the British physicist Otto Robert Frisch, went on to explain the process of nuclear fission in 1939, placing the release of atomic energy within reach.