Accidental Nobel

The Nobel Prize is the most prestigious recognition in several fields in Sciences and Humanities, it is awarded to people who have achieved remarkable discoveries or actions. However, this award is not immune to casual discoveries; one example is that of Arno Penzias and Robert Wilson.

Expanding universe

Nowadays, the “Big Bang” theory is the leading and most accepted theory to describe the universe origin, and although it has been valid for more than 80 years, its origins were difficult given the initial rejection it had from the most eminent scientists of that time, who still considered as correct the theory of a static universe that would remain unaltered forever.

Georges Lemaître

Georges Lemaître (Wikipedia.org)

The Big Bang was a theory initially proposed by Georges Lemaître, who proposed his “primal atom” hypothesis, which based on calculations derived from Einstein’s general theory of relativity presented an image of an expanding universe; but even Einstein emphatically rejected this idea, commenting to Lemaître that “His calculations were correct, but his physics was abominable.” But as we know, this was later experimentally tested with Edwin Hubble’s discoveries, which were proof that the universe is expanding. In the end, this indicator was so overwhelming and irrefutable that finally, years later, even Einstein finally accepted this theory and personally made an emphatic acknowledgment to Lemaître, making clear the significance of his theory.

Gamow and the Big bang afterglow

George Gamow, another remarkable theoretical physicist from Ukraine, also made an important contribution in relation to the Big Bang theory, making the prediction that the remaining radiation of this explosion, after the 13.7 billions of years of the cosmos would have “cooled”, and with it would be emitting low frequency radiation, which would eventually fill the universe with a glow or remnant of electromagnetic radiation (or light), in the microwaves frequency range, with a temperature of about five degrees above absolute zero (Absolute zero is zero degrees Kelvin or minus 459.67 degrees Fahrenheit).

This prediction on the cosmic microwave background radiation, remainder from the Big Bang, was published its scientific paper “The origin of chemical elements” in 1948, this had as coauthors Ralph Alpher and Hans Bethe (the latter added only with the intention of making a play on words and having the first three letters of the Greek alphabet “αβγ”, as Alpher, Bethe and Gamow), this is why this scientific paper is known as the “αβγ” [Alpha-Beta-Gamma] paper.

The prediction on the microwave background radiation from Gamow was repeated (arguing a forgetfulness of it), by Robert Dicke, a physicist from Princeton who, making the same prediction, began the search for this radiation using a microwave detector from his own invention (a Dicke radiometer), but this search was short lived, because another team had gone ahead.

The accidental discovery

Arno Penzias, who was born in Germany, being of Jewish descent, when World War II started his family moved away from Germany as refugees, finally settling in New York, in the United States; he had his academic training as a Physicist, and after graduating he served in the Navy for a while; then he began his post-graduate studies at Columbia University, where he obtained his Physics doctorate in the early sixties. Later he went to work on the famous Bell laboratories in New Jersey.

At Bell Laboratories, he formed a team with Robert Wilson where they worked on ultra-sensitive microwave receivers for use in radio astronomy research, mainly to read the microwave signal from the Milky Way (among other applications). For this purpose, they used an antenna in the form of a horn. The 15-meter Holmdel horn antenna, which acts as a wave-guide, which is a way of transmitting signals by using rectangular section metallic tubes, hence this name.

Holmdel Horn Antenna

Holmdel Horn Antenna at Bell Lab. (Wikipedia.org)

And while they carried-on their investigations they faced an unforeseen situation; The signal they received on their antenna included a high level of noise, with a temperature three degrees higher than what they estimated, for which they could not identify its origin. This was a much weaker signal than that received from the Milky Way and was also isotropic; this means, it seemed to be homogeneous and uniform in all directions to which its antenna pointed.

Trying to identify the source of this noise, they first tried by checking if their equipment had any problems; conditions such as defects in equipment wiring were reviewed, but no problems were detected; then they considered other sources of radiation, such as radiation emitted by nearby New York City that is located only 20 miles away, or due to high-altitude nuclear tests conducted in those years, after these verification there were no conclusive results. Another possibility that was explored was what Penzias described as “a cover of white dielectric material” inside the antenna could be the cause of this noise, this due to the presence of a pair of pigeons that lived in it. So, they initially trapped the pigeons and moved them with a breeder in upstate New York. But in just a few days they were back in their “home”; so, they had to take a more drastic decision, which we may say, didn’t ended favorably for these pigeons.

But after this action, they noticed that the pigeons were innocent, because the noise persisted even after having removed the “white dielectric material”. At this point Penzias and Wilson began a search for a possible explanation of this noise, consulting multiple scientific papers, but again without much success. It was until Penzias had an encounter with Bernard Burke, a radio astronomer from the Department for Terrestrial Magnetism, that he suggested contacting Robert Dicke at Princeton University.

The CMB (Cosmic Microwave Background Radiation).

Penzias and Wilson contacted Dicke, who with his team was working on the search for the CMB signal, just as his theoretical models predicted it, as proof of the Big Bang being the universe’s origin. Although they were not ready to make measurements, and upon receiving this call Dicke immediately identified what they had discovered. When he finished his first conversation with Pensiaz and Wilson, Dicke went back to his laboratory and told his colleagues “Boys, we’ve been scooped”.

For Dicke it was clear that the signal that Penzias and Wilson identified was the proof he was looking for, this finding was published in the “Astrophysical Journal”, as an article with an obscure and understated title in physics; “A measurement of excess antenna temperature at 4080 Mc/s”. But hidden in this article there was one of the greatest physics discoveries of all times, the evidence of the Big Bang, the evidence of the beginning of the universe; and this discovery was for what they were recognized with the Physics Nobel Prize in 1978.

This discovery, although it was a stroke of luck, in no way undermines the work that Penzias and Wilson did to conclude what this noise was about. What is interesting in this case is that Science is not always based on moments of “eureka”, it does not always arrive spontaneously after “the apple falls or the water overflows from a bathtub”.

Science is discovery, and it is not always based on “Eureka” moments, it requires precision, tenacity and dedication. The discovery of Penzias and Wilson is the sound of the beginning of time, the remnant of heat of the Big Bang, the three degrees that have not yet cooled down, resulting from the beginning of the universe, the origin of everything and all; this is the sound of the moment in that the whole universe was in communion, and which indeed happened, 13.7 billion years ago.

You can hear this CMB noise, and knowing what it represents, listening to it is simply inspiring.

Regards, Alex; ScienceKindle!

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