The discovery of cosmic microwave background radiation is a major development in modern physical cosmology. The cosmic background radiation (CMB) was measured by Andrew McKellar in 1941 at an effective temperature of 2.3 K using the CN star absorption line observed by W. S. Adams. Theoretical work circa 1950 indicates that the need for CMB for consistency with the simplest model of the relativistic universe. In 1964, US radio astronomers Arno Penzias and Robert Woodrow Wilson rediscovered the CMB, estimating its temperature as 3.5 K, as they experimented with Horn Antenna Holmdel. New measurements were accepted as important evidence for a hot early Universe (big bang theory) and as evidence against competing steady state theories. In 1978, Penzias and Wilson were awarded the Nobel Prize for Physics for their joint measurement.
Video Discovery of cosmic microwave background radiation
History
In the mid-20th century, cosmologists have developed two different theories to explain the creation of the universe. Some support the steady-state theory, which states that the universe is always there and will continue to survive without any real change. Others believe in the Big Bang theory, which states that the universe was created in a big boom like the events of billions of years ago (later determined to be 13.72 billion) (13,720 million).
In 1941, Andrew McKellar used spectroscopic observations of WS Adams from CN uptake lines in the spectrum of type B stars to measure the black background temperature of 2.3 K. McKellar refers to his detection as "atomic molecular temperature rotation", without reference to cosmological interpretations, which states that the temperature "will have its own, may be limited, of significance".
Over two decades later, working at Bell Labs in Holmdel, New Jersey, in 1964, Arno Penzias and Robert Wilson experimented with a 6-meter (20-foot) horn antenna originally built to detect radio waves that bounced off the Echo balloon satellite. To measure these dimmed radio waves, they must eliminate all identifiable interference from their receivers. They eliminate the effects of radar and radio broadcasting, and suppress interference from heat in the receiver itself by cooling it with liquid helium to -269 Â ° C, just 4 K above absolute zero.
When Penzias and Wilson reduce their data, they find a low, stable, and mysterious voice that survives in their recipients. This remaining sound is 100 times stronger than they think, spread evenly in the sky, and is present day and night. They believe that the radiation they detect at a 7.35 cm wavelength does not come from Earth, the Sun, or our galaxy. After examining their equipment thoroughly, removing some pigeons nesting in the antenna and cleaning up the accumulated dirt, the sound remained. Both conclude that these sounds come from outside our own galaxy - though they are not aware of any radio source that will explain it.
At the same time, Robert H. Dicke, Jim Peebles, and David Wilkinson, astrophysicists at Princeton University just 60 km (37 mi), are preparing to look for microwave radiation in the region of the spectrum. Dicke and his colleagues argued that Big Bang must have spread not only condensed matter into galaxies but also must have unleashed a tremendous radiation outburst. With proper instrumentation, this radiation must be detectable, though as a microwave, due to a massive redshift.
When a friend (Bernard F. Burke, Professor of Physics at MIT) told Penzias about the precast paper he saw by Jim Peebles about the possibility of finding the remaining radiation from the explosion that filled the universe early in its existence, Penzias and Wilson began to realize the significance of what which they believe to be new inventions. The radiation characteristics detected by Penzias and Wilson correspond to the radiation predicted by Robert H. Dicke and his colleagues at Princeton University. Penzias called Dicke at Princeton, who promptly sent him an unpublished copy of Peebles paper. Penzias read the paper and called Dicke again and invited him to Bell Labs to see the antenna horn and listen to the background sound. Dicke, Peebles, Wilkinson, and P. G. Roll interpret this radiation as a signature of the Big Bang.
To avoid potential conflicts, they decided to publish their results together. Two notes were taken to Astrophysical Journal Letters. At first, Dicke and his colleagues outlined the importance of cosmic background radiation as a proof of the Big Bang Theory. In a second note, jointly signed by Penzias and Wilson entitled, "A Measurement of Excess Temperature Temperatures at 4080 Megacycles per Second," they reported a background noise of 3.5 K residual, remaining after accounting for the 2.3 K absorption component of the sky the instrumental component is 0.9 K, and links the "possible explanation" as given by Dicke in his companion letter.
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