Thomas Gold
Thomas Gold was an Austrian-born astrophysicist, who also held British and American citizenship. He was a professor of astronomy at Cornell University, a member of the U.S. National Academy of Sciences, and a Fellow of the Royal Society. Gold was one of three young Cambridge scientists who in 1948 proposed the now mostly abandoned "steady state" hypothesis of the universe. Gold's work crossed boundaries of academic and scientific disciplines, into biophysics, astronomy, aerospace engineering, and geophysics.
Early life
Gold was born on May 22, 1920, in Vienna, Austria, to Max Gold, a wealthy Jewish industrialist who ran one of Austria's largest mining and metal fabrication companies, and German former actress Josefine Martin. Following the economic downfall of the European mining industry in the late 1920s, Max Gold moved his family to Berlin, where he had taken a job as director of a metal trading company. Following the start of Nazi leader Adolf Hitler's anti-Jewish campaigns in 1933, Gold and his family left Germany because of his father's heritage. The family travelled through Europe for the next few years. Gold attended boarding school at the Lyceum Alpinum Zuoz in Zuoz, Switzerland, where he quickly proved to be a clever, competitive and physically and mentally aggressive individual. Gold finished his schooling at Zuoz in 1938, and fled with his family to England after the German invasion of Austria in early 1938. Gold entered Trinity College, Cambridge in 1939 and began studying mechanical sciences. In May 1940, just as Hitler was commencing his advance in Belgium and France, Gold was sent into internment as an enemy alien by the British government. It was on the first night of internment, at an army barracks in Bury St Edmunds, that he met his future collaborator and close friend, Hermann Bondi.Gold spent most of his nearly 15 months of internment in a camp in Canada, after which he returned to England and reentered Cambridge University, where he abandoned his study of mechanical sciences for physics. After graduating with a pass degree in June 1942, Gold worked briefly as an agricultural labourer and lumberjack in northern England before joining Bondi and Fred Hoyle on naval research into radar ground clutter near Dunsfold, Surrey. The three men would spend their off-duty hours in "intense and wide-ranging scientific discussion" on topics such as cosmology, mathematics and astrophysics. Within months, Gold was placed in charge of constructing new radar systems. Gold determined how landing craft could use radar to navigate to the appropriate landing spot on D-Day and also discovered that the German navy had fitted snorkels to its U-boats, making them operable underwater while still taking in air from above the surface.
Schooling and work in England
Immediately after the war, Hoyle and Bondi returned to Cambridge, while Gold stayed with naval research until 1947. He then began working at Cambridge's Cavendish Laboratory to help construct the world's largest magnetron, a device invented by two British scientists in 1940 that generated intense microwaves for radar. Soon after, Gold joined R. J. Pumphrey, a zoologist at the Cambridge Zoology Laboratory who had served as the deputy head of radar naval research during the war, to study the effect of resonance on the human ear.Theory of human hearing
Via simple experimentation in 1946, Gold found that the degree of resonance observed in the cochlea was not in accordance with the level of damping that would be expected from the viscosity of the watery liquid that fills the inner ear. As recounted by Freeman Dyson, who was one of the fellow students at Cambridge whom Gold experimented on, the procedure was "simple, elegant, and original." Gold built his experimental apparatus out of war surplus Navy electronics and headphones. This was equipment that Gold had used during his World War II assignment to the Royal Navy as a radar and radio communications specialist.In 1948 he published two papers on his results; one described the theory and the other reporting the experimental results. His theory was that the ear operates instead in the same way as does a "regenerative radio receiver" by adding energy at the same frequency it is trying to detect. Although Gold won a prize fellowship from Trinity College for his thesis on this proposed mechanism of hearing and obtained a junior lectureship at the Cavendish Laboratory, his theory was widely ignored by ear specialists and physiologists, such as future Nobel Prize winner Georg von Békésy, who did not believe the cochlea operated under a feedback system. Later, however, researchers discovered that Gold's hypothesis had been correct. As reported in one of the science obituaries published about Gold in 2004, "Ignored for over 30 years, his research was rediscovered in the 1970s when physiologists discovered the tiny hair cells that act as amplifiers in the inner ear."
Steady-state theory
Gold began discussing problems in physics with Hoyle and Bondi again, centering on the issues over redshift and Hubble's law. This led the three to all start questioning the Big Bang theory originally proposed by Georges Lemaître in 1931 and later advanced by George Gamow, which suggested that the universe expanded from an extremely dense and hot state and continues to expand today. As recounted in a 1978 interview with physicist and historian Spencer R. Weart, Gold believed that there was reason to think that the creation of matter was "done all the time and then none of the problems about fleeting moments arise. It can be just in a steady state with the expansion taking things apart as fast as new matter comes into being and condenses into new galaxies".Two papers were published in 1948 discussing the "steady-state theory" as an alternative to the Big Bang: one by Hermann Bondi and Gold, the other by Fred Hoyle. In their seminal paper, Bondi and Gold asserted that although the universe is expanding, it nevertheless does not change its look over time; it has no beginning and no end. They proposed the perfect cosmological principle as the underpinning of their theory, which held that the universe is homogeneous and isotropic in space and time. On the large scale, they argued that there "is nothing outstanding about any place in the universe, and that those differences which do exist are only of local significance; that seen on a large scale the universe is homogeneous." However, since the universe was not characterized by a lack of evolution, distinguishing features or recognizable direction of time, they postulated that there had to be large-scale motions in the universe. They highlighted two possible types of motion: large-scale expansion and its reverse, large-scale contraction. They estimated that within the expanding universe, hydrogen atoms were being created out of a vacuum at a rate of one atom per cubic meter per 109 years. This creation of matter would keep the density of the universe constant as it expanded. Gold and Bondi also stated that the issues with time scale that had plagued other cosmological theories – such as the discrepancy between the age of the universe as calculated by Hubble and dating of radioactive decay in terrestrial rocks – were absent for the steady-state theory.
It was not until the 1960s that major problems with the steady-state theory began to emerge, when observations apparently supported the idea that the universe was in fact changing: quasars and radio galaxies were found only at large distances, not in closer galaxies. Whereas the Big Bang theory predicted as much, steady state predicted that such objects would be found everywhere, including close to our own galaxy, since evolution would be more evenly distributed, not observed only at great distances. In addition, proponents of the theory predicted that in addition to hydrogen atoms, antimatter would also be produced, as with cosmic gamma ray background from the annihilation of protons and antiprotons and X-ray emitting gas from the creation of neutrons.
For most cosmologists, the refutation of the steady-state theory came with the discovery of the cosmic microwave background radiation in 1965, which was predicted by the Big Bang theory. Stephen Hawking said that the fact that microwave radiation had been found, and that it was thought to be left over from the Big Bang, was "the final nail in the coffin of the steady-state theory." Bondi conceded that the theory had been disproved, but Hoyle and Gold remained unconvinced for a number of years. Gold even supported Hoyle's modified steady-state theory; however, by 1998 he started to express some doubts about the theory, but maintained that despite its faults, the theory helped improve understanding regarding the origin of the universe.