From The Editor | December 20, 2023

Unveiling Scientific Frontiers: The Impact of Solvay Conferences on Modern Science

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By John Oncea, Editor

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The early Solvay Conferences on Physics played a significant role in the evolution of Physics in the 20th century. Started in 1911, they are still regarded as one of the world's premier conferences in physics and chemistry, and, in 1927, are where Niels Bohr told Albert Einstein to “stop telling God what to do.”

The 1927 New York Yankees, featuring the “Murderers Row” of batters, are considered to be one of the finest baseball teams ever assembled. The roster included six Hall of Famers, led by the legendary Babe Ruth and his then Major League-record 60 home runs. The Yanks won 110 games and capped off the ’27 season by sweeping the National League champion Pittsburgh Pirates four games to none in the World Series.

Two weeks after New York wrapped up the Series with a 4-3 win at Yankee Stadium on October 8 another Murderers Row was assembled 3,600 miles away in Brussels, Belgium. Led by Albert Einstein and Niels Bohr, 18 past or future Nobel Prize winners – including Marie Curie, recipient of Nobel prizes in two separate scientific disciplines – attended the Fifth Solvay International Conference on Electrons and Photons.

Oh, and in case you felt my using baseball to introduce an article for a site about photonics felt a little forced I have three words for you: the Magnus effect. Named after Heinrich Gustave Magnus, the German physicist who investigated it, the Magnus effect is the generation of a sidewise force on a spinning cylindrical or spherical solid immersed in a fluid (liquid or gas) when there is relative motion between the spinning body and the fluid.

You know, like when a baseball pitcher throws a curveball, a pitch where one side of the ball has more friction than the other causing the air to flow faster on the side with more friction, creating a lower-pressure region on the opposite side with the resulting force of the Magnus effect perpendicular to the rotation axis and in the direction the front surface of the ball is moving.

See? Not forced at all.

Leading Off

The Solvay Conferences are considered by many to be the premier conference in physics and chemistry and have played an important role in the history and development of science. It was at the very first conference, held in 1911 at the Hotel Métropole in Brussels, that Einstein met Henri Poincaré in an uncomfortable moment that, in the long run, changed the world.

“At the end of this session, Poincaré said that Einstein’s presentation was so different from what physics should be — namely that it could be represented with causal interactions, with good differential equations, with clear presentations of principles and consequences — that he simply found it unbearable, and ended by making it clear that what Einstein was saying was so contradictory that anything could follow from it,” writes “It was a disaster for science, he thought.

“Einstein for his part went home and scribbled a note to a friend in which he recounted the wonderful work that had been done by various colleagues, how much he admired, even loved, the physicist Hendrik Lorentz, but disparaged Poincaré who simply seemed to understand nothing. They passed like ships in the night, each, on relativity, unable to acknowledge the other’s existence. Yet a few weeks after their ill-starred meeting, Poincaré wrote a letter of recommendation for Einstein for a job that was very important to him. It was a stunning letter that said, essentially, that this young man may well be up to some of the greatest things, and even if only a few of his wild ideas turn out to be true he’s a person of extraordinary importance. It was a letter of enormous grace and generosity. They never directly exchanged another word and never met again.”

Hendrik Lorentz was the chairperson of this inaugural conference, the subject of which was Radiation and the Quanta, and attendees looked at the problems of having two approaches, namely classical physics and quantum theory.

Following the success of the inaugural summit, the organization and execution of the event have been under the watchful eye of the International Solvay Institutes, founded by the Belgian industrialist Ernest Solvay in 1912. The Institute for Chemistry was founded 10 years later and then merged in 1970 to become the International Solvay Institutes for Physics and Chemistry, founded by Ernest Solvay.

Recent Solvay Conferences entail a three-year cycle: the Solvay Conference on Physics followed by a gap year, followed by the Solvay Conference on Chemistry. This cycle has been perturbed by many factors in the past – including World Wars I and II – and it has been decided to adhere to it more strictly in the future, with a prominent role played again by the scientific committees and the chairs of the conferences.

The success of the Solvay Conferences can be attributed to their highly organized structure. An international scientific committee is responsible for determining the conference's general theme and selecting a chairperson. The conference chair is in charge of creating the program, which includes choosing specific topics and sessions as well as determining who will be invited to participate.

The Solvay Conferences are known for their focus on discussions rather than presentations. The conferences are typically split into half-day sessions, with each session starting with a report or two that reviews the current state of the subject. These reports are distributed to all participants before the start of the conference. The reports are then followed by lively discussions moderated by the session chair.

Over the years, Solvay Conferences have become renowned for their role in shaping the course of physics in the 20th century. They convened periodically, discussing various crucial topics such as the nature of light, quantum mechanics, statistical mechanics, and the structure of matter.

These conferences provided a platform for intense debates, collaboration, and the exchange of ideas among the brightest minds in science. They played a pivotal role in laying the groundwork for some of the most fundamental theories in modern physics and chemistry. Although the Solvay Conferences have evolved, their legacy remains significant in the history of scientific inquiry.

A Grand Slam For Science

The 1927 conference, also chaired by Lorentz, was devoted to electrons and photons but was dominated by the emerging field of quantum mechanics with discussions centered around the theory’s interpretation and implications, according to Britannica.

In addition to Einstein, Bohr, and Curie, the 1927 Solvay Conference was attended by an All Star team of scientists and researchers (and Nobel Prize winners, noted in bold) including Auguste Piccard, Émile Henriot, Paul Ehrenfest, Édouard Herzen, Théophile de Donder, Erwin Schrödinger, JE Verschaffelt, Wolfgang Pauli, Werner Heisenberg, Ralph Fowler, Léon Brillouin, Peter Debye, Martin Knudsen, Lawrence Bragg, Hendrik Anthony Kramers, Paul Dirac, Arthur Compton, Louis de Broglie, Max Born, Irving Langmuir, Max Planck, Hendrik Lorentz, Paul Langevin, Charles-Eugène Guye, CTR Wilson, and Owen Richardson.

This home movie shot Langmuir captures two minutes of an intermission in the proceedings and features many of the attendees.

One highlight of this monumental conference was that it hosted a debate between Einstein and Bohr that laid down the foundations for quantum physics, a theory that has enabled the development of technologies that are vital in our everyday lives, such as energy and digital communications.

“Beginning in 1925 Bohr, Heisenberg, and Born, among others, had formed what came to be known as the ‘Copenhagen interpretation’ of quantum mechanics, which postulated that the indeterminacy in the theory (i.e., that only the probability of a result could be predicted) was fundamental and should be accepted by scientists,” writes Britannica. “There was no underlying deterministic order to be found.

“Some physicists, most notably Einstein, did not accept the Copenhagen interpretation and felt that its reliance on indeterminacy showed that quantum mechanics still was not a complete theory. That dispute was foregrounded at the 1927 conference. Bohr, Heisenberg, and Born were not able to win Einstein over, but the dissemination of the Copenhagen interpretation among physicists was accelerated by the conference, and it eventually became the prevailing view of quantum mechanics.”

Alive And Kicking

The early Solvay Conferences are thought to have been turning points in the world of physics and chemistry and are responsible for the most intelligent photo ever taken. The International Solvay Institute for Chemistry celebrated its 100th anniversary in 1922 and, along with its counterpart for physics, has been gathering the world’s most brilliant scientific minds in world-renowned conferences for well over 100 years.

“It was during one of these conferences in the 1950s, writes Syensqo, “that the scientific community validated the existence of the double helix structure of DNA, for example. A website was recently created, Solvay Science Project, to make the archives of these conferences available to all, in collaboration with the Université Libre de Bruxelles that conserves them.”

More recently, the Science for the Future Solvay Prize was and is awarded every two years. Katalin Kariko received the latest prize for her work on the biochemical modification of synthetically produced messenger RNA. Two previous laureates, Carolyn Bertozzi and Ben Feringa, went on to win Nobel Prizes in Chemistry.