Earth and Space

Zwicky’s modesty

Stories from Physics for 11-14 14-16 IOP RESOURCES

In 1932, James Chadwick discovered the neutron and Lev Landau predicted the existence of neutron stars. Two years later, the Bulgarian/Swiss astronomer Fritz Zwicky developed Landau’s concept and made some detailed predictions about their behaviour. His seemingly outlandish ideas were lampooned in an Associated Press cartoon ‘Be Scientific With OL’DOC DABBLE’. The caption of the cartoon read:

Cosmic rays are caused by exploding stars which burn with a fire equal to 100 million Suns and then shrivel from 1/2 million mile diameters to little spheres 14 miles thick, says Prof. Fritz Zwicky, Swiss Physicist.

Four decades later, his ideas vindicated, Zwicky referred to the cartoon: “This, in all modesty, I claim to be one of the most concise triple predictions ever made in science.”

An article describing Zwicky’s contribution suggests that: “When researchers talk about neutron stars, dark matter, and gravitational lenses, they all start the same way: ‘Zwicky noticed this problem in the 1930s. Back then, nobody listened…’.” It is remarkable that Zwicky, with his colleague Baade, predicted the transition from supernova to neutron star in 1934, only two years after the discovery of the neutron. The pair are also responsible for coining the term ‘supernova’ to distinguish the events from ordinary novae.

Zwicky can also claim the creation of the first artificial meteors. He loaded rockets with high explosives which detonated after launch to generate jets of liquid metal and could then be photographed by astronomers to gain a better understanding of the formation of meteors. During one of these liquid metal experiments in 1957, one of the jets escaped the Earth and is thought to be the first artificial object to orbit the Sun.

Zwicky is reported to have been a pugnacious character - he referred to his enemies as “spherical bastards” because they looked like bastards from any angle. He even boasted to Millikan: “I have a good idea every two years. You name the subject, I bring the idea.” However, he proposed a number of less successful notions, including a jet plane that could burrow through the Earth.


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