Freeman Dyson at Harvard University in 2004

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. In 1957, he became a naturalized citizen of the United States.

In the years following the war, Dyson was responsible for demonstrating the equivalence of the two formulations of quantum electrodynamics which existed at the time - Richard Feynman's path integral formulation and the variational methods developed by Julian Schwinger and Sin-Itiro Tomonaga (Dyson operator).

From 1957 to 1961 he worked on the Orion Project, which proposed 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 scientific papers, Dyson theorized that a technologically advanced society could completely surround its native star in order to maximize the capture of the star's available energy. Eventually, the civilization would completely enclose the star, intercepting electromagnetic radiation with wavelengths from visible light downwards and radiating waste heat outwards as infrared radiation. Therefore, one method of searching for extraterrestrial civilisations would be to look for large objects radiating in the infrared range of the electromagnetic spectrum. Dyson conceived that such structures would be clouds of asteroid-sized space habitats, though science fiction writers have preferred a solid structure: either way, such an artifact is often referred to as a Dyson sphere. The most famous example was illustrated in an episode of Star Trek: The Next Generation, in which retired Engineer Scotty (from the original Star Trek) was discovered to have crash-landed on an abandoned Dyson Sphere.

Dyson has also proposed the creation of a Dyson tree , a genetically-engineered plant capable of growing on a comet. He suggested that comets could be engineered to contain hollow spaces filled with a breathable atmosphere, thus providing self-sustaining habitats for humanity in the outer solar system.

Dyson has published a number of collections of speculations and observations about technology, science, and the future:

• Imagined Worlds
• From Eros to Gaia
• Disturbing the Universe

As of 2003, Dyson is the president of the Space Studies Institute , the space research organization founded by Gerard K. O'Neill.

He has six children. One daughter is Esther Dyson. His son is the historian of technology George Dyson, one of whose books is Project Orion: The Atomic Spaceship 1957-1965. Despite sharing a last name, he is not related to early 20th-century astronomer Frank Watson Dyson. However as a small boy Freeman Dyson was aware of him and credits him with inadvertently helping to spark his interest in science.

Freeman John Dyson was awarded the Max Planck medal in 1969.

He was the 2000 winner of the Templeton Prize for Progress in Religion.

See also

• A.I. Shlyakhter
• Dyson's eternal intelligence
• Astrochicken

External links

• Freeman J. Dyson's homepage
• Space Studies Institute
• Wired magazine interview
• audio of NPR interview with Freeman Dyson
• Gravity is Cool, or, Why our Universe is Hospitable to Life, text of the Oppenheimer lecture, given at the University of California in Berkeley, California on March 9, 2000 by Freeman J. Dyson, of the Institute for Advanced Study, Princeton, New Jersey.