Born on Valentine’s Day in 1898, visionary Swiss astronomer Fritz Zwicky devoted most of his life advancing observational and theoretical astronomy. Zwicky was considered by many to be quite an original or unconventional thinker, which often led his ideas to be disregarded. One of his most celebrated discoveries is that of the neutron star and coining the term “supernova.”

Fritz Zwicky (Image: totallyhistory
Fritz Zwicky (Image: totallyhistory)

Background and education

Fritz Zwicky was the oldest son of a Swiss man, Fridolin, and his Czech wife. He was born in the city of Varna in Bulgaria, where his father was a prominent industrialist. However, at the early age of six, the young Zwicky moved away from Bulgaria to Switzerland in the canton of Glarus, where he would reside with his grandparents. Behind this was the intention that Zwicky was to study commerce as he arrived in Switzerland but despite these wishes of his father, his interests slowly started to shift towards mathematics and physics, and he would thus pursue his later studies at ETH (Eidgenössische Technische Hochschule), the Swiss Federal Polytechnic institute in Zurich.

At the age of 27, in 1925, Zwicky immigrated to the USA to work at Caltech, the California Institute of Technology, with American physicist Robert Millikan famous for his work on the photoelectric effect.

Scientific contributions made by Fritz Zwicky

Zwicky’s early scientific work in the 1930s touched on the physics of the solid states, where he studied ionic crystals and electrolytes, notably under the lens of gaseous ionization and thermodynamics. Still, his interest quickly turned to more prominent fields in astrophysics. He worked in close collaboration with Walter Baade to coin the term “supernova,” hypothesizing that they were the transitional state between a normal star and a neutron star.

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Besides, both deduced that supernovae were the reason behind the origin of cosmic rays, high-energy protons, and atomic nuclei that move through space at speeds close to the speed of light. A year later, in 1935, Zwicky used the first Schmidt camera, a catadioptric astrophotography telescope that he used to observe wide fields of view. This helped him support his supernova hypothesis, allowing him to find 120 by himself during extensive research on the neighboring galaxies from 1937 to 1941.

Fritz Zwicky at the Schmidt telescope at Palomar Observatory, California, in the 1930s
Image: Palomar Observatory/Caltech
Fritz Zwicky at the Schmidt telescope at Palomar Observatory, California, in the 1930s
Image: Palomar Observatory/Caltech

By observing these galaxies, Fritz Zwicky also concluded, in 1937, that they could act as gravitational lenses. In short, the galaxies – due to their large mass – would bend the light coming from cosmic objects located behind them and allow the astronomer to observe them despite the galaxy being in the way. Unfortunately, however, the experimental confirmation only came about 40 years later. But his work on galaxies was not over. From 1961 to 1968, Zwicky spent a considerable amount of time cataloging all the galaxies he had and observing, allowing him to publish a six-volume “Catalogue of galaxies and clusters of clusters of galaxies.”

Another considerable discovery that arose from his observation of galaxies was a conjecture on the dark matter, which he coined, originally as “Dunkle Materie.” In examining the Coma galaxy cluster, he observed a gravitational anomaly: an excessive rotational velocity of luminous or regular matter “(about 400 times the expected one) compared to the calculated gravitational attraction this regular matter would generate within the cluster. This discrepancy strongly suggested another type of matter that would be invisible but would also play into gravitational attraction. Although Zwicky’s proportions were later proved to be too large, he correctly inferred that the great majority of the matter was a “dark” one.

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Despite his groundbreaking work and unforeseen genius, Fritz Zwicky was often regarded by other scientists of the community as arrogant, with a reputation for a somewhat rash and unpredictable character, which somewhat alienated and failed to give him the recognition he deserved, his contributions remaining virtually unheard of by the general public. Indeed, he often referred to his peers who ridiculed him as “the useless trash in the bulging astronomical journals” or even went as far as making the bold statement for which is best known: “Some Astronomers are spherical bastards. No matter how you look at them, they are just bastards“.

His relatives and peers thus remembered Fritz Zwicky as a mastermind and as a curmudgeon. This “original thinking” of his led to Zwicky often making bold claims, being quick to judge and disregard, but at times being mistaken. This, in turn, alienated quite some of his peers. For example, in talking to a Ph.D. student from Caltech who needed some help on a thesis surrounding oxygen-gasoline rocket engines, Fritz Zwicky boldly asserted that he “must realize that a rocket could not operate in space as it required the atmosphere to push against to provide thrust,” quasi disregarding the whole basis of this student’s thesis only to realize later that he had been mistaken.

The Most Controversial Astronomer In History Who Changed Our Understanding Of The Universe. 1
Fritz Zwicky with many leading scientists of his day. Front row (from left): Robert Oppenheimer, Harry Bateman, Richard Tolman, William Houston, Robert Millikan, Albert Einstein, Paul Sophus Epstein, Zwicky, Ernest Charles Watson. (Image: AIP Emilio Segrè Visual Archives)

Nonetheless, despite the controversies surrounding Fritz Zwicky’s at times rough-edged personality, he will be remembered as a pioneer and unconventional sideways thinker whose original takes on many problems and observations allowed considerable advancements to be made in various fields of astronomy.

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