Scientific Advancement and Nuclear Fission

Advances in scientific understanding often do not build directly or smoothly in response to the data that are amassed, and in retrospect, after a major revision of theory, it may seem strange that a crucial hypothesis was long overlooked. A case in point is the discovery of a means by which the compiled increasing evidence that nuclear fission had been achieved, without, however, recognizing what they were witnessing.

Earlier, even before the neutron and proton composition of atomic nuclei had been experimentally demonstrated, some theoretical physicists had produced calculations indicating that in principle it should be possible to break atoms apart. But the neutron-bombardment experiments were not aimed at achieving such a result, and researchers were not even receptive to be analogous to a pebble, thrown through a window, causing a house to collapse.

In Berlin, Meitner pursued research related to that of the Italians, discovering a puzzling group of radioactive substances produced by neutron bombardment of uranium. Fermi and others achieved numerous similar results. These products remained unidentified partly because precise chemical analyses were hampered by the minute quantities of the substances produced and the of the experiment, added up to the number of such particles that compose a uranium nucleus.

It was Meitner who finally recognized the significance of the data in relation to underlying theoretical considerations: the researchers had actually been splitting uranium atoms. Coining the term “nuclear fission,” she quickly submitted her conclusion for publication in a paper coauthored with physicist Otto Frisch. When scientists in Europe and North America had been present for some time, lacking mainly the right conceptual link.