1918

Nobel Prize in Physics

A Desperate Trick Became a New Physics

Max Planck

In the autumn of 1900, Max Planck was trying to resolve a stubborn embarrassment: the existing equations of classical physics predicted that a heated object should radiate infinite energy at short wavelengths — a result so catastrophically wrong it had been nicknamed the ultraviolet catastrophe. To make his formula fit experimental data, Planck inserted a mathematical assumption he found thoroughly uncomfortable: that energy could only be absorbed or emitted in discrete packets, which he called quanta, each proportional to frequency by a constant now bearing his name. He called it a formal trick, an act of desperation, and spent several years attempting to dissolve the assumption back into classical mechanics. It would not dissolve. By the time the Nobel arrived in 1918, a full eighteen years after the fact, quantum mechanics had grown into an edifice so strange that Planck himself — one of its unwilling architects — professed to find it unsettling. He had pulled a loose thread expecting to tie it off, and instead unravelled the fabric of classical physics. Without that desperate act of 1900, there is no transistor, no laser, no MRI scanner — and the screen on which you are reading this sentence would be physically impossible to explain.

Nobel Prize in Chemistry

Air Into Bread, Air Into Gas

Fritz Haber

By the start of the twentieth century, the world's agriculture was running up against a hard ceiling: nitrogen, essential to plant growth, was available in usable form only from guano deposits and Chilean saltpetre, both finite. Fritz Haber cracked the problem between 1909 and 1913, devising a catalytic process to combine atmospheric nitrogen and hydrogen at high temperatures and pressures to produce ammonia at industrial scale — the raw material for synthetic fertiliser. The Haber-Bosch process, as it was commercialised, now supports perhaps half of all the nitrogen in the human food supply, meaning that roughly half the people alive today owe their existence in some sense to a single German chemist. The complication, for any attempt at a clean narrative, is that this same chemist supervised Germany's chemical weapons programme during the First World War, overseeing the first large-scale deployment of chlorine gas at Ypres in 1915, and would later develop Zyklon in a form that descendants of the process would put to uses he did not anticipate. The Allied nations made their displeasure at the 1918 prize award known, with some vigour. Haber remains the most morally uncomfortable Nobel laureate in the history of the prize — a man who fed the world and helped poison it in the same working lifetime.

Emmy Noether proves her symmetry theorem

Symmetry Was the Reason All Along

On 26 July 1918, Emmy Noether presented a theorem so fundamental that physicists would spend the rest of the century discovering new ways to be grateful for it. The insight was this: every continuous symmetry of a physical system corresponds exactly to a conserved quantity — time-translation symmetry gives energy conservation, spatial translation gives momentum, rotational symmetry gives angular momentum. This is not a result sitting inside physics like a useful formula; it is a result about physics, explaining at a single stroke why conservation laws exist at all rather than merely that they do. The theorem unified what had seemed like separate empirical observations into consequences of geometry, and it underpins everything from classical mechanics to the Standard Model of particle physics. The context in which Noether proved it adds a certain bitter wit: she was at the time still in an administrative dispute with the University of Göttingen over whether she was permitted to give lectures under her own name, having been admitted to the faculty only by the intervention of David Hilbert, who had reportedly grown weary of the objections and asked what her sex had to do with mathematics. The theorem bears her name. The lectureship took longer.

Shapley maps the Milky Way's true structure

Evicted Again, This Time From the Galaxy

For most of human history, the Sun occupied, at least implicitly, a position near the centre of whatever arrangement of stars surrounded it — Copernicus had deposed us from the centre of the solar system, but the galaxy seemed politely to have left us somewhere respectable. Harlow Shapley ended that comfort in 1918. Working at the Mount Wilson Observatory, he used Cepheid variable stars in globular clusters as distance markers — their period of pulsation being tightly linked to their intrinsic luminosity, so brightness on the sky becomes a reliable ruler — and measured the distances to dozens of clusters scattered across the sky. The clusters, he found, were arranged in a vast spheroid whose centre lay some 30,000 light-years away in the direction of Sagittarius, not anywhere near the Sun. We were out in the suburbs of our own galaxy, not at the hub. The reassignment of address was almost philosophically rude: having been evicted from the centre of the solar system, humanity now learned it was also off-centre within the one galaxy it had managed to map. Shapley's numbers were not perfectly accurate by modern standards, but the structural conclusion was correct, and it set the terms for every subsequent account of where, precisely, we are.

Spanish influenza pandemic

The Young and Strong Fell Hardest

The first wave of what became known as the Spanish influenza appeared in early 1918 — probably in the United States, though the name stuck to Spain because Spanish newspapers, uncensored by wartime restrictions, were among the few to report it honestly. It swept the globe in three waves over roughly two years, infecting an estimated 500 million people, perhaps a third of the world's population at the time, and killing somewhere between 25 and 50 million of them, with later estimates running higher still. It killed more people than four years of industrial warfare had managed, and it did so in months. What made it peculiarly disturbing was the pattern of mortality: where influenza usually claims the elderly and the very young, this strain killed robust adults in their twenties and thirties, apparently by triggering the immune system into a self-destructive overreaction — a cruel inversion of vigour. The pandemic closed in on a world already exhausted by war, killed some at the armistice celebrations in November 1918, and vanished as capriciously as it had arrived, leaving behind a scientific mystery about its origins and severity that would not be substantially resolved until researchers recovered viral material from permafrost nearly a century later.

Nova Aquila observed

A New Star, Briefly Brighter Than Noon Would Allow

On the night of 8 June 1918, a star abruptly appeared in Aquila where none of significance had been catalogued before, climbing within hours to a visual magnitude of 1.4 — briefly bright enough to be seen in daylight and the most spectacular nova since Kepler had watched his own star flare in 1604. Astronomers trained telescopes on it within hours and found it dimming over subsequent days and weeks in a pattern that yielded, under careful spectroscopic study, a great deal of information about the expanding shell of gas being hurled outward from the eruption. What a nova actually was remained imperfectly understood in 1918; the prevailing and not entirely wrong notion was that it involved some kind of stellar explosion or collision, and the full picture — a white dwarf in a binary system accreting hydrogen from a companion until the surface ignites in thermonuclear runaway — would not solidify until decades later. Nova Aquila 1918, designated GK Persei in the modern catalogue, endures as a useful laboratory for studying that process in the shell still expanding, at a measured pace, through the present day.