Freeman John Dyson (born December 15, 1923) is an English-born
American physicist and mathematician. He worked as an analyst
for the British Bomber Command during World War II; after the
war, he moved to Princeton. Soon after the war Dyson was the
first physicist who realised Q.E.D theory has 2 different faces.
One face was researched by Richard Feynman alone and the other
one by Julian Schwinger and Sin-Itiro Tomonaga. From 1957 to
1961 he worked on the Orion project, which demonstrated the
possibility of space-flight using nuclear propulsion: a
prototype was demonstrated using conventional explosives, but a
treaty banning the use of nuclear weapons in space caused the
project to be abandoned. In one of his papers, he made the
observation that it was possible that a growing technological
society would increasingly surround its native star so as to
maximise the capture of available energy. The end point of this
process would be the complete enclosure of the star; all
wavelength from visible light downwards be