The goal of science is to understand and explain the phenomenal world. In this effort one often has to interpret what is observed, for the deeper cause of what meets the eye is often hidden from direct perception. Sometimes, that deeper cause may be of enormous significance and its revelation may have unexpected impact on the course of history.
Consider, for example, the series of reports that were circulating in the late 1930s to the effect that when uranium nuclei were bombarded by neutrons, the resulting products contained radioactive isotopes which were far removed on the periodic table from uranium itself. In particular, in a paper published on 6 January 1939, Otto Hahn and Fritz Strassmann announced that radioactive barium of atomic number 56 was a product of such bombardment of uranium whose atomic number is 92. This was very intriguing to physicists at the time. The correct interpretation for this was provided by Otto Frisch (born: 1 October 1904) and his aunt Lise Meitner. In a letter to Nature, that appeared on 16 January of the same year, they wrote the memorable line: “It seems possible that the uranium nucleus has only small stability of form, and may after neutron capture, divide into two nuclei of roughly equal size.”
At that time, Frisch, an Austrian by birth of Jewish extraction, had become a persona non grata in Germany and Austria. He was among the many who had migrated to England or the Scandinavian countries before moving on to the United States. He was then working at the Institute of Theoretical Physics in Copenhagen. W. A. Arnold, an American biologist, who was also there, and heard about Frisch’s idea, suggested that the phenomenon was very much like the splitting of cells, called fission. Frisch thought this was an appropriate term in this context too. So was born both the idea and the name for what we call nuclear fission today: a microcosmic phenomenon whose discovery has had the most drastic consequences on human civilization and history.
The following year, Frisch moved to Cambridge, England, where he joined the team of nuclear physicists which included James Chadwick, the discoverer of the neutron.
Now started the dark period of World War II. Secret projects were afoot. The best brains were drawn for this. They wanted to whisk away Frisch from England to the United States, to make him part of the Manhattan Project. But technically he was an enemy alien, and there were visa problems. So he first had to become a British citizen, take the oath of allegiance, get a British passport, and volunteer for National Service. This had to be deferred, and other formalities had to be done before he could board the ship that would take him to the USA. Rudolf Peierls with whom Frisch worked in Cambridge, narrates all this in his book Atomic Histories. So it was that Frisch joined the constellation of physicists, chemists, mathematicians, and engineers who pooled in their resources in the Manhattan Project to create the most destructive weapon in history.
In his brief autobiography, entitled What little I remember, Frisch recalls appreciatively the rugged Rockies, the brilliant sunshine, the red flowers of the cacti and their spiny bush, the extinct crater Valle Grande, the aspens turning, the Rio Grande, etc. of New Mexico, reminding us that physicists can be as observant of natural beauties and as sensitive as any poet. But here he also recalls the accidental deaths of scientists while they were doing experiments with radioactive materials.
The work of Otto Frisch reveals above all that the mind’s eye is often more penetrating than the brightest light: its capacity to unveil appearances is what constitutes science.
October 5, 2013