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'''Robert Henry Dicke''' (1916-1997) was one of the most accomplished American-born [[physicist]]s and experimental physicists in history.  He made significant contributions to [[radar]], atomic physics, [[cosmology]], quantum optics, gravity physics, and astrophysics.  Like the great British physicist [[Fred Hoyle]], Dicke paid a heavy price for criticizing a theory favored by [[liberals]] (the [[Theory of Relativity]]): Dicke was denied a Nobel Prize.

'''Robert Henry Dicke''' (1916-1997) was one of the most accomplished American-born [[physicist]]s and experimental physicists in history.  He made significant contributions to [[radar]], atomic physics, [[cosmology]], quantum optics, gravity physics, and astrophysics.  Although he was an incredibly prolific scientist and inventor Dicke never won a Nobel Prize.

A tribute by his colleagues, Princeton Professors W. Happer, P. J. E. Peebles, and D. T. Wilkinson, summed up Professor Dicke's career as follows:<ref>http://bob.nap.edu/html/biomems/rdicke.html (emphasis added).</ref>

A tribute by his colleagues, Princeton Professors W. Happer, P. J. E. Peebles, and D. T. Wilkinson, summed up Professor Dicke's career as follows:<ref>http://bob.nap.edu/html/biomems/rdicke.html (emphasis added).</ref>

:Bob held some 50 patents, from clothes dryers to lasers. He recognized that two mirrors make a more effective laser than the traditional closed cavity of microwave technology. In the company Princeton Applied Research he and his students packaged his advances in phase-sensitive detection in the now-ubiquitous "lock-in amplifier." '''With its successors this probably has contributed as much to experimental Ph.D. theses as any device of the last generation.''' Bob predicted and experimentally showed that collisions that restrict the long-range motions of radiating atoms in a gas can suppress Doppler broadening. The physics is the same as that of Mössbauer narrowing of gamma-ray lines; it is used in the atomic clocks of the Global Positioning System. He contributed to the concept of adaptive optics in astronomy. He was among the first to recognize that the accepted gravity theory, general relativity, could and should be subject to more thorough tests. His series of gravity experiments mark the beginning of the present rich network of tests. He set forth the idea of the anthropic principle that now plays a large part in speculation on what our universe was doing before it was expanding. Bob's visualization of an oscillating universe stimulated the discovery of the cosmic microwave background, the most direct evidence that our universe really did expand from a dense state. A key instrument in measurements of this fossil of the [[Big Bang]] is the microwave radiometer he invented.

:Bob held some 50 patents, from clothes dryers to lasers. He recognized that two mirrors make a more effective laser than the traditional closed cavity of microwave technology. In the company Princeton Applied Research he and his students packaged his advances in phase-sensitive detection in the now-ubiquitous "lock-in amplifier." '''With its successors this probably has contributed as much to experimental Ph.D. theses as any device of the last generation.''' Bob predicted and experimentally showed that collisions that restrict the long-range motions of radiating atoms in a gas can suppress Doppler broadening. The physics is the same as that of Mössbauer narrowing of gamma-ray lines; it is used in the atomic clocks of the Global Positioning System. He contributed to the concept of adaptive optics in astronomy. He was among the first to recognize that the accepted gravity theory, general relativity, could and should be subject to more thorough tests. His series of gravity experiments mark the beginning of the present rich network of tests. He set forth the idea of the anthropic principle that now plays a large part in speculation on what our universe was doing before it was expanding. Bob's visualization of an oscillating universe stimulated the discovery of the cosmic microwave background, the most direct evidence that our universe really did expand from a dense state. A key instrument in measurements of this fossil of the [[Big Bang]] is the microwave radiometer he invented.

Professor Dicke was a critic of the [[theory of relativity|theory of general relativity]] as formulated by [[Albert Einstein]]. Instead, Dicke supported an alternative theory with Professor Carl Brans known as the Brans-Dicke theory, which includes a scalar field in addition to the tensor field defined by general relativity. At one point in 1970, after some testing of both theories, Dicke stated publicly that he stood by his theory against Einstein's.<ref>http://www.time.com/time/magazine/article/0,9171,943324,00.html</ref> The differences between Brans-Dicke and general relativity are slight, and both explain currently observable data.

==The Brans-Dicke Theory of Gravitation==

While Dicke accepted [[Theory of Relativity|Relativity]], both special and general, he believed that plain General Relativity did not fully explain gravity. Along with his former student Carl Brans, he formulated the Brans-Dicke theory, which includes a scalar field in addition to the tensor field defined by general relativity. This "scalar-tensor theory" (as opposed to plain relativity, which is just a "tensor theory") included a scalar field, usually denoted &omega;, which, when assigned a certain value, they believed matched experimental data better.  (When &omega; is set to infinity, the Brans-Dicke theory becomes equivalent to plain General Relativity.)  Brans and Dicke suggested a value of about 5.  The observable differences between Brans-Dicke and general relativity are extremely tiny.

 

Dicke was instrumental in proposing extremely sensitive tests of General Relativity.  Modern measurements of the various tests, specifically from Mariner 6 spacecraft in 1969, and the Cassini spacecraft in 2004, show that plain Einsteinian relativity, not the Brans-Dicke theory, agrees with observation.<ref>http://content.time.com/time/magazine/article/0,9171,943324,00.html</ref> <ref>http://www.jpl.nasa.gov/releases/70s/release_1970_0566.html</ref> <ref>[https://books.google.com/books?id=9ZuP9JQzc00C&pg=PA157&lpg=PA157&dq=brans-dicke%2Bmariner&source=bl&ots=Y2jhf2OjcU&sig=C8qWD1E5ukCe_5DiKObCiWjAEKg&hl=en&sa=X&ei=cCw9VcfBE8HksASynoHICw&ved=0CDkQ6AEwBQ#v=onepage&q=brans-dicke%2Bmariner&f=false The Rise and Fall of the Brans-Dicke Theory]</ref>  Nevertheless, interest in the Brans-Dicke formulation has recently revived, in the context of dark matter / dark energy investigations.

==Biography==

==Biography==

Dicke was born on May 6, 1916 in St. Louis, [[Montana]]. He received a bachelor’s degree from Princeton University in 1939, as well as a doctorate from the University of Rochester in 1941. In the same year he became a staff scientist at the radiation laboratory of MIT. In 1975 he was appointed Albert Einstein professor of science and nine years later he became emeritus professor.<ref>http://www.britannica.com/EBchecked/topic/162137/Robert-H-Dicke</ref>

Dicke was born on May 6, 1916 in St. Louis, [[Montana]]. He received a bachelor’s degree from Princeton University in 1939, as well as a doctorate from the University of Rochester in 1941. In the same year he became a staff scientist at the radiation laboratory of MIT. In 1975 he was appointed Albert Einstein professor of science and nine years later he became emeritus professor.<ref>http://www.britannica.com/EBchecked/topic/162137/Robert-H-Dicke</ref>

Dicke was closely related to the 1978 [[Nobel Prize]] for Physics. The 1978 physics prize went to Arno Penzias and Robert Wilson, who first measured the [[cosmic background radiation]], though Dicke was the theorist who explained it.<ref>http://www.nps.gov/history/history/online_books/butowsky5/astro4k.htm and http://www.astrosociety.org/pubs/mercury/9404/dicke.html</ref> Some people think that the 1978 Nobel Prize was awarded in a manner to punish Dicke for his criticism of Relativity.  Indeed, Dicke should have won the Nobel Prize for one of his many other achievements also (such as his laser work), but was similarly denied recognition.

Dicke's work was closely related to that of Arno Penzias and Robert Wilson, who first measured the [[cosmic background radiation]], though Dicke was the theorist who explained it<ref>http://www.nps.gov/history/history/online_books/butowsky5/astro4k.htm and http://www.astrosociety.org/pubs/mercury/9404/dicke.html</ref>.  The 1978 [[Nobel Prize]] for Physics was awarded to Penzias and Wilson, but not Dicke, for this work.  Some people think that this was unfair, and that Dicke should also have won the Nobel Prize for any of his many other achievements also (such as his laser work).

== References ==

== References ==