A summary of the development of the big bang theory is an interesting interplay of theoretical and experimental/observational science. The red dates are the theoretical contributions, all others are exp/obs. :
SUMMARY
1814 – Joseph Fraunhofer invented the spectroscope and discovered dark lines in the sun’s spectrum
1859 – Gustav Kirchhoff and Robert Bunsen found that the frequencies of the dark spectral lines found in sunlight corresponded to the frequencies of bright lines produced when chemical elements are activated to glow in the laboratory. When a spectroscope is attached to a telescope astronomers are able to tell what stars are made of.
1912 – Henrietta Leavett discovered a method for determining the distance to stars called Cepheid variables
1914 – Vesto Slipher announced that characteristic spectral lines observed in the light from nebulae were not at frequencies one would expect; instead they were shift toward the red side of the spectrum.
1915 – Einstein introduced the General Theory of Relativity. When Einstein solved the equation for the universe he found the solution predicted an expanding universe. In order to conform to the existing paradigm that held that the universe was static, he introduced a constant, since referred to as the cosmological constant.
1922 – Alexander Friedman found that Einstein made a mathematical mistake; but even with the cosmological constant, the relativity equation predicted an expanding universe.
1924 - Edwin Hubble focused the new 100 inch Mt. Wilson reflecting telescope on the nebulae and was able to resolve individual stars. He found Cepheid variables and used Leavitt’s technique to measure the distance to the nebulae and found them to be outside our Milky Way galaxy. They were separate galaxies; the Universe was much bigger than previously assumed.
1929 – Hubble analyzed the red shifts in the spectral lines from distant galaxies and noticed that the more distant a galaxy from our own, the larger the red shift. This meant that the farther away the receding galaxies were from our galaxy, the higher the velocity of recession. This could only mean that the universe was expanding.
1931 – Father Georges Lemaitre independently recreated the Freidman model, realized that expansion was real and proposed that the universe expanded from an infinitely small object called the ‘primeval atom’.
1948 – George Gamow and his student Ralph Alpher applied classical thermodynamics and nuclear physics to the primeval atom and predicted that the remnants of the expansion would be a background of energy measuring about 5 degrees Kelvin. In addition, this work also predicted the relative abundance of lithium and beryllium by a process of nucleosynthesis.
1964 - Jim Peeples, Robert Dicke, et.al. at Princeton University, apparently without knowledge of Gamow’s prediction, offered their own prediction that there should be a detectable remnant of the big bang; the remnant has since become known as the cosmic background radiation (CBR).
1964 - Two BTL engineers at Holmdel, NJ, Arno Penzias and Robert Wilson, were troubled by a noise from all parts of the sky while setting up a radio telescope to be used for wireless communication. The Princeton group realized that the remnant that they and Gamow’s group predicted was the signal observed by Penzias and Wilson, thus verifying the big bang theory.
Subsequently the prediction of the distribution of light elements was also verified by observation adding additional validation of the theory,
Also the observed distribution of galaxies in the various stages of evolution provides additional support for the BB theory
The Noble Prize was won by Wilson and Penzias, for their accidental observation.
Yppop
