In the German Museum in Munich is the experimental setup that solved the mystery of the origin of the universe – three gray boxes the size of refrigerators. The Munich native and later Nobel Prize winner in physics Arno Penzias donated it to the museum – to remember what Germany lost during the Nazi era through the expulsion and murder of Jews, like Penzias’ daughter according to the New York Times once said in an interview.
Arno Penzias was born on April 26, 1933 in Munich. His Jewish family narrowly escaped deportation to Poland in 1938. Six-year-old Penzias and his brother arrived in England on a British children’s transport. From there the family emigrated to the USA in 1940, where Penzias later studied physics. Arno Penzias was known for his discovery of the so-called cosmic background radiation, for which he received the Nobel Prize together with Robert W. Wilson in 1978.
In 1964, the two radio astronomers employed at Bell Laboratories actually wanted to use an antenna to examine the Milky Way in more detail. But an interference frequency ran through all of their measurements, no matter in which direction they turned the radio telescope. They initially thought that noise was the source of the disturbing signal, they considered radar and atomic radiation, and the two physicists even cleaned pigeon droppings from the bottom of the antenna, whose shape is reminiscent of a huge horn. That could have been the reason.
Robert W. Wilson, left, and Arno Penzias in front of the horn-shaped antenna with which they captured signals from the Big Bang for the first time.
(Photo: ASSOCIATED PRESS)
It was only by chance that Penzias and Wilson became aware of the work of theorists at Princeton University, and the crucial clue was that what was buzzing so annoyingly through the measurement was not an interference signal, but the first light of the universe, created in the Big Bang at the beginning of time and space . This light passes through the entire universe as a so-called cosmic microwave background.
This ended the great debate about the origins of the cosmos: the universe must have been created by a huge bang at one point and had been expanding ever since. There was already some evidence for this theory in the 1960s: Edwin Hubble published his observation in 1929 that distant galaxies were moving away and it followed from Albert Einstein’s general theory of relativity from 1915 that the universe must be expanding.
But the great competing theory of the time, the “steady-state universe” could also explain the receding galaxies – and did not contain a starting point of all existence that was barely comprehensible to human imagination. Instead, according to steady state, the universe always existed and space and time extended evenly within it. However, the discovery of the strange microwave background left physicists with only one conclusion: there must have been a Big Bang.
The discovery of the cosmic microwave background not only explained the formation of the universe. Accurate maps of background radiation are still being studied today. They show slight fluctuations in which experts can fathom properties of the early universe.
After his discovery, Arno Penzias remained as a researcher at Bell Labs for almost 40 years. He died on Monday in San Francisco. He was 90 years old. The outer parts of the horn antenna still stand on a hill in Holmdel, New Jersey, and the receiver and other equipment remain in the German Museum in Munich.