Hantaro Nagaoka was the world’s first scientist to present a Saturnian model of the atom

Though some atom models were proposed in the world of physics in the early 20th century, it was Hantaro Nagaoka, then professor at the University of Tokyo, who was the first to presented a Saturnian atomic model close to the presently accepted model.

In 1897, J. J. Thomson of Britain discovered the electron. At the same time, Wilhelm Conrad Rontgen discovered X-rays and Maria Sklodowska-Curie discovered radium. At the time, new discoveries concerning nuclear physics came one after another, and attention was focused on the structure of the atom.

In those days Nagaoka was the first to defend a Saturnian atomic model that looks like Niels Bohr’s atomic model in that the electrons orbit like Saturn’s rings around the nucleus which itself contains a positive electric charge. Nagaoka announced this at the Tokyo society for mathematics and physics in December 1903, and he also announced it the following year in the British academic journal “Philosophical Magazine“.

At the same time, Thomson, who had discovered the electron, was in favour of the “Plum pudding model”. This model described atoms as electropositive balls that had electrons scattered in them, like the raisins in raisin bread. A lot of physicists supported this model even though it was quite different from Bohr’s well-known atomic model.

On the other hand, the model of Nagaoka led to speculation that the electrons turning around the atomic nucleus would slowly lose energy and ultimately collide with the nucleus. For this model to be correct, an explanation had to be found why this was not happening. There was no experimental proof, and moreover, it was not supported, except by some scholars, such as Lodge and Poincare.

However, eight years later, in 1911, Ernest Rutherford announced an experimental test for the atom model of the atomic nucleus in 1911 and after that, Bohr announced a more detailed atom model in 1913, which showed that Nagaoka’s model was closer to reality than the Thomson model.

The model of Nagaoka was announced several years before the announcements by Rutherford and Bohr, and it can be called an extremely advanced model even though it was not properly evaluated because it came too early.