Zwicky: The Outcast Genius Who Unmasked the Universe

John Johnson Jr, author of Zwicky, tells the fascinating life story of the imaginative and abrasive astrophysicist Fritz Zwicky, providing historical context and also biographies of colleagues and combatants (often one and the same).

Zwicky’s influence on astrophysics begins in the past, with the initial encouragement of European physics professors to come to America, for in the mid-19th century, America was behind Europe. By 1899 there were enough trained physicists to hold the first American Physical Society (APS) meeting.

At the time of the first APS meeting, member numbers were mostly from the east coast, so the meeting was held in New York. But by 1930, numbers had shifted to the west.  Robert Millikan, while employed by Caltech, won the Nobel Prize in physics for measuring the charge on an electron, and Earnest O Lawrence, at Berkeley, built the first particle accelerator, and in 1933, the APS met in California at Stanford.

At this meeting of the APS, most papers were on the topic of cosmic radiation and the mystery of their source, which heralded the birth of high-energy astrophysics, and it is here that the author introduces the reader to Fritz. In 1933, Fritz Zwicky was a 35-year old Swiss-German physicist on staff at the Mount Wilson Observatory.

Zwicky co-authored a paper with Walter Baade, which was presented at the APS; it offered a new set of theories on supernovae and cosmic rays, that cosmic rays came from outer space, and also that one of the causes of cosmic rays was supernovae. Zwicky also proposed a theory that a supernova transformed an ordinary star into a neutron star by catastrophic collapse. These theories were novel in that the neutron itself had only been discovered the year before, and that only a few supernovae had been observed. Supernovae were so little understood at that time, the word used for them before supernovae coined, was “temporary stars.”

Johnson next provides a summary of modern astrophysics, pointing out that Zwicky entered the race for making discoveries at the time where “idea of a cosmos of billions of galaxies each containing billions of stars, was beyond the reach of most people’s imaginations.” Zwicky and Baade’s theory was not taken well, though Zwicky welcomed opposition. He considered opposition as a sign of rather than being ignored, as proof he was on the right track.

Years later though parts of Zwicky and Baade’s theory were proved wrong, the overall idea was correct, including the mass of a star that could supernova, and the frequency of occurrence. The discovery in 1934 that cosmic rays did not come from Earth, vindicated Zwicky. But it took decades (not until 1967) to detect the existence of neutron stars.

Though most physics theories, like Einstein’s, were hard to understand, supernovae, the idea of exploding stars, was easy for the layperson to understand, and Zwicky and Baade’s theory attracted media attention. In Baltimore in 1935, Zwicky gave a radio talk on physics, distant galaxies, neutron stars, and black holes. Told simply, the talk was fascinating and far-sighted, and made him famous.

Some of Zwicky’s ideas were considered crazy at that time, and for years after, too. For example, Zwicky wanted to hit the moon with a rocket to see if it held water (the idea was not too crazy by 2009, when it was tried by NASA).

Johnson provides photo plates of Zwicky through the years. Zwicky was born in Glarus, Switzerland, the capital of the Canton of Glarus. Before WWI, Zwicky’s father moved his family to Varna, Bulgaria, to sell textile machinery, and when Zwicky turned six, he was sent to live with his grandparents for schooling in Switzerland. In school, Zwicky discovered he had an aptitude for mathematics and also for coding—while learning shorthand, Zwicky invented his own, making his diaries unreadable. Also, while in school, Zwicky made lifelong friends with Tadeusz Reichstein, who later won the Nobel Prize in medicine.

Johnson provides short biographies of the famous astrophysicists working at that time, so the readers get a feel for Zwicky’s peers. Some need only a single name to be recognized today, such as Einstein, Hubble, and Schrodinger. Perhaps less recognizable are (though not in any particular order), Harlan Shapely, Walter Baade, Milton Humason, Rudolph Minkowski, Allan Sandage, Ralph Elmer Wilson, Frederick Hanley Seares, Horace Welcome Babcock, Georges Lemaitre, and Vesto Slipher.

In 1916 Zwicky enrolled for engineering in the Swiss University, ETH, barely a generation after Einstein, who had been a professor there. Zwicky was sheltered from the worst of WWI in Switzerland, except for food shortages and street riots. Later, in graduate school, Zwicky changed his field of study from engineering to teaching and became a teacher’s assistant in the ETH physics department.

In 1925, the Rockefeller Foundation came to Europe to hire staff for American universities, offering more than $1M in grants overall. Among those the Rockefeller Foundation hoped to interview at ETH was Peter Debye, a mathematician and friend of Einstein. Debye wasn’t in town; instead, Zwicky offered to give the visitors a tour of the university. Zwicky made an impression and was offered a two-year International Fellowship. At this point in his career, Zwicky had no training in astronomy, and his grant was for graduate work on crystal properties. Living in the mountainous Glarus region, Zwicky had become a lifelong enthusiast in mountaineering, and so he chose to take his fellowship at the Mount Wilson Observatory located in the San Gabriel Mountain range near Pasadena.

Zwicky was ambivalent about leaving Switzerland. He was proud of being Swiss but also believed the Swiss people to be insular. Though Zwicky lived in America for the rest of his life, he never fully acculturated, never became a citizen, and sent his children to be educated at Swiss boarding schools. However, in the early years, Zwicky more or less liked his colleagues at Caltech, and more or less grew to like America.

When Zwicky’s fellowship ended in 1927, he was appointed to a Caltech professorship, and changed his research from crystals to astrophysics on a dare to “do something great” by Robert Millikan, his boss at Caltech. In return, Zwicky called Millikan “unimaginative.” This was normal behavior for Zwicky. Theodore Von Karman, a Hungarian-American aerospace engineer at Caltech tells this story about Zwicky, “He [von Karman] once told Fritz he was thinking of coining a term for the roughness of an aerodynamic surface. He would call it a Zwicky, he said. But then he realized that nothing could measure up to the boldness of a full Zwicky, but the man himself. ‘So the practical unit will be a micro-Zwicky.’”

Another indication of Zwicky’s style was, that for all his life, he refused to believe in the expanding universe theory and its cause, the Big Bang. Zwicky to the end of his life believed that the universe was static, and that light lost energy by getting “tired” and turned red when traveling over long distances. Zwicky, later in life, began to use red shifted data, but he never recanted publicly.

During the years leading to WWII, Zwicky broke with Baade over rivalry, but perhaps more importantly because Baade was a Nazi. During WWII, American scientists were routinely redirected from academics to research that could directly help the war effort, and Zwicky was directed toward rocket research by von Karman, to find ways to improve takeoff for airplanes on short runways. For this, Zwicky partnered with von Karman to form the Aerojet corporation. Zwicky came up with the solution, a better JATO, but his improvement, which required industrial scaling to support the war effort, came too late for use. But by the end of the war Zwicky had his name on 18 patents.

Zwicky traveled to Germany at the end of the war to debrief the German rocket corps, and interviewed Werner von Braun as part of Operation Paperclip. According to Zwicky, America may have been ten years behind Germany in rocketry but this was due to funding and not from innate ability. For his effort, Zwicky received the Presidential Medal of Honor, the first such honor given to a non-citizen.

Zwicky was also sent as part of a fact-finding trip to Hiroshima and Nagasaki barely three months after the atom bombs were dropped. What he saw turned him into a critic of nuclear war, though he did believe such a war would be survivable. To this end he wrote and published an “our friend the atom” pamphlet that described how a family could survive a nuclear attack, and Zwicky’s company, Aerojet, soon began building parts of ICBMs. Zwicky also supervised an Airforce project on investigations into UFO sightings, Project Blue Book, and worked on an unnamed secret project on biological warfare.

After the war, astrophysicists returned from war work to science. The Hale telescope, part of the Palomar Observatory, was dedicated in June 1948. The Hale was a huge 200-inch telescope built to detect the expansion of the universe, and its use led to new discoveries about star formation, the size of the universe, and the big bang. Johnson has a good feel for the day-to-day work of an astronomer before computers and digital cameras, where cameras took recorded data on photographic plates, where “data from a single exposure could take weeks to analyze.”

As for Zwicky’s renewed work in astrophysics, he was forced to use lesser telescopes, spending nights over years taking images on optical plates, searching for supernovae. The Hale was in operation three years before Zwicky was allowed to touch it, despite his prominence. And as Zwicky was not an American citizen, his security clearance at Aerojet was revoked in the 1950s, part of increased security measures taken during the McCarthy era. The powers that be agreed that Zwicky’s security clearance would quickly be restored if he started the paperwork to become a U.S. citizen. Zwicky stubbornly refused to do so, even refusing a bribe from Aerojet that would increase his pension. Zwicky, ever intransigent, was forced out of Aerojet in 1961, two years away from retirement.

Zwicky remained determined to continue teaching at Caltech. But around this time, he also ran into difficulties getting his scientific papers published, because of the standard of practice of scientific journals to refuse to publish papers containing conjecture without evidence or analysis. Reading his colleague’s discoveries in these same journals, Zwicky believed he was not receiving proper credit. Zwicky became more eccentric and bitter.

Having always feuded with his colleagues, Zwicky turned it up a notch. A feud with Allan Sandage escalated to the point where Caltech administrators asked to Zwicky to tone it down, and when Zwicky did not, he was forced to retire at the age of 68. Once retired, the Mount Wilson Observatory was justified in taking away Zwicky’s observing time.

Despite retirement, Zwicky was allowed to keep an office in the basement of Caltech. There he cataloged galaxies, looking for supernovae. In 1968, when Zwicky was 70, his theory about neutron stars was proven by Jocelyn Bell, earning her advisor, Antony Hewish, a Nobel Prize.

Zwicky was better at finding anomalies than overarching theories. Zwicky is known for a six-volume catalog that serves as a systematic survey of galaxies and galaxy clusters, that took almost a decade to complete. The catalog includes 40,000 objects, including faint blue stars. Zwicky’s final catalog in the series, was published in 1971, and had a 27-page introduction that he used to settle scores. In it, Zwicky accused scientists including Hubble and Baade of falsifying their observations.

The faint blue stars also turned out to be quasars, which put a “nail in the coffin” of the steady-state universe. That they were quasars was discovered not by Zwicky but by a colleague Maarten Schmidt, who did not credit Zwicky. And so, another feud ensued.

In 1972, Zwicky won a gold medal from the Royal Astronomical Society of England. Still researching at the age of 76, he died of a heart attack in 1974. Zwicky’s ashes were interred in Switzerland.

John Johnson Jr’s writing is in the vein of popular science, so he will have a more appreciative audience in those in search of a good story rather than of the details of scientific discovery. Here though, Johnson perhaps overdoes the “popular” part of popular science. He avoids not just math and physics, but also the type of explanation that is necessary when one avoids math and physics—the greatest depth in science Johnson feels comfortable with is an explanation of the Doppler Effect.

As for narrative, Johnson has a tendency to jump back and forth over many years within chapters, and often back and forth over many years across paragraphs. Though the intent may be to explain Zwicky’s arc of personal contradictions, and the long-term consequences of events across time, jumping time makes it more difficult for a reader to maintain a sense of when is now in the narrative. Another, though a relatively minor issue, is that not all of Zwicky’s life is interesting, or told in an interesting manner, and some of the looser parts should have been tightened, or expanded with greater detail, or even removed, which could be done without harming the storyline.