First conference Hendrik Lorentz was chairman of the first Solvay Conference on Physics, held in Brussels from 30 October to 3 November 1911. The subject was
Radiation and the Quanta. This conference looked at the problems of having two approaches, namely
classical physics and
quantum theory.
Albert Einstein was the second youngest physicist present (the youngest one was
Frederick Lindemann). Other members of the
Solvay Congress were experts including
Marie Skłodowska-Curie,
Ernest Rutherford and
Henri Poincaré (see image for attendee list).
Third conference The third Solvay Conference on Physics was held in April 1921, soon after
World War I. Most German scientists were barred from attending. In protest at this action,
Albert Einstein, although he had renounced German citizenship in 1901 and become a Swiss citizen (in 1896, he renounced his German citizenship, and remained officially stateless before becoming a Swiss citizen in 1901), declined his invitation to attend the conference and publicly renounced any German citizenship again. Because anti-Semitism had been on the rise, Einstein accepted the invitation by Dr.
Chaim Weizmann, the president of the World Zionist Organization, for a trip to the United States to raise money.
Fourth conference The fourth Solvay Conference on Physics was held in 1924. These conferences, supported by the King of Belgium, had become the leading international gathering for the discussion of the very latest developments in physics. The subject was "The electrical conductivity of metals and related topics". Scientists based in Germany and Austria were not invited to this Solvay meeting due to the tensions still prevailing after the First World War. So there was no Planck, Einstein, Sommerfeld or Born.
Fifth conference Perhaps the most famous conference was the fifth Solvay Conference on Physics, which was held from 24 to 29 October 1927. The subject was
Electrons and Photons and the world's most notable physicists met to discuss the newly formulated quantum theory. The leading figures were Albert Einstein and
Niels Bohr. Seventeen of the 29 attendees were or became
Nobel Prize winners, including
Marie Skłodowska-Curie who, alone among them, had won Nobel Prizes in two separate scientific disciplines. The anti-German prejudice that had prevented Einstein and others from attending the Solvay conferences held after the First World War had melted away. Essentially all of those names who had contributed to the recent development of the quantum theory were at this Solvay Conference, including Bohr, Born, de Broglie, Dirac, Heisenberg, Pauli, Planck, Lorentz, Compton, Ehrenfest, and Schrödinger.
Heisenberg commented: "Through the possibility of exchange between the representatives of different lines of research, this conference has contributed extraordinarily to the clarification of the physical foundations of the quantum theory. It forms, so to speak, the outward completion of the quantum theory." The photo taken of this conference's participants is sometimes entitled "The Most Intelligent Photo Ever Taken," for its depiction of the world's leading physicists gathered together in one shot. == Solvay conferences on physics ==