einstein

electromagnetic phenomena.
Up until then, Einstein had published five little-noted papers. They had earned him neither a doctorate nor a teaching job, even at a high school.
Had he given up theoretical physics at that point, the scientific community would not have noticed, and he might have moved up the ladder to
become the head of the Swiss Patent Office, a job in which he would likely have been very good indeed.
There was no sign that he was about to unleash an annus mirabilis the like of which science had not seen since 1666, when Isaac Newton, holed
up at his mother’s home in rural Woolsthorpe to escape the plague that was devastating Cambridge, developed calculus, an analysis of the light
spectrum, and the laws of gravity.
But physics was poised to be upended again, and Einstein was poised to be the one to do it. He had the brashness needed to scrub away the
layers of conventional wisdom that were obscuring the cracks in the foundation of physics, and his visual imagination allowed him to make
conceptual leaps that eluded more traditional thinkers.
The breakthroughs that he wrought during a four-month frenzy from March to June 1905 were heralded in what would become one of the most
famous personal letters in the history of science. Conrad Habicht, his fellow philosophical frolicker in the Olympia Academy, had just moved away
from Bern, which, happily for historians, gave a reason for Einstein to write to him in late May.
Dear Habicht,
Such a solemn air of silence has descended between us that I almost feel as if I am committing a sacrilege when I break it now with some
inconsequential babble . . .
So, what are you up to, you frozen whale, you smoked, dried, canned piece of soul ...? Why have you still not sent me your dissertation?
Don’t you know that I am one of the 1½ fellows who would read it with interest and pleasure, you wretched man? I promise you four papers in
return. The first deals with radiation and the energy properties of light and is very revolutionary, as you will see if you send me your work first.
The second paper is a determination of the true sizes of atoms ... The third proves that bodies on the order of magnitude 1/1000 mm,
suspended in liquids, must already perform an observable random motion that is produced by thermal motion. Such movement of suspended
bodies has actually been observed by physiologists who call it Brownian molecular motion. The fourth paper is only a rough draft at this point,
and is an electrodynamics of moving bodies which employs a modification of the theory of space and time. 7
Light Quanta, March 1905
As Einstein noted to Habicht, it was the first of these 1905 papers, not the famous final one expounding a theory of relativity, that deserved the
designation “revolutionary.” Indeed, it may contain the most revolutionary development in the history of physics. Its suggestion that light comes not
just in waves but in tiny packets—quanta of light that were later dubbed “photons”—spirits us into strange scientific mists that are far murkier,
indeed more spooky, than even the weirdest aspects of the theory of relativity.
Einstein recognized this in the slightly odd title he gave to the paper, which he submitted on March 17, 1905, to the Annalen der Physik: “On a
Heuristic Point of View Concerning the Production and Transformation of Light.” 8 Heuristic? It means a hypothesis that serves as a guide and gives
direction in solving a problem but is not considered proven. From this first sentence he ever published about quantum theory until his last such
sentence, which came in a paper exactly fifty years later, just before he died, Einstein regarded the concept of the quanta and all of its unsettling
implications as heuristic at best: provisional and incomplete and not fully compatible with his own intimations of underlying reality.
At the heart of Einstein’s paper were questions that were bedeviling physics at the turn of the century, and in fact have done so from the time of
the ancient Greeks until today: Is the universe made up of particles, such as atoms and electrons? Or is it an unbroken continuum, as a gravitational
or electromagnetic field seems to be? And if both methods of describing things are valid at times, what happens when they intersect?
Since the 1860s, scientists had been exploring just such a point of intersection by analyzing what was called “blackbody radiation.” As anyone
who has played with a kiln or a gas burner knows, the glow from a material such as iron changes color as it heats up. First it appears to radiate
mainly red light; as it gets hotter, it glows more orange, and then white and then blue. To study this radiation, Gustav Kirchhoff and others devised a
closed metal container with a tiny hole to let a little light escape. Then they drew a graph of the intensity of each wavelength when the device
reached equilibrium at a certain temperature. No matter what the material or shape of the container’s walls, the results were the same; the shape of
the graphs depended only on the temperature.
There was, alas, a problem. No one could fully account for the basis of the mathematical formula that would produce the hill-like shape of these
graphs.
When Kirchhoff died, his professorship at the University of Berlin was given to Max Planck. Born in 1858 into an ancient German family of great
scholars, theologians, and lawyers, Planck was many things that Einstein was not: with his pince-nez glasses and meticulous dress, he was very
proudly German, somewhat shy, steely in his resolve, conservative by instinct, and formal in his manner. “It is difficult to imagine two men of more
different attitudes,” their mutual friend Max Born later said. “Einstein a citizen of the whole world, little attached to the people around him,
independent of the emotional background of the society in which he lived—Planck deeply rooted in the traditions of his family and nation, an ardent
patriot, proud of the greatness of German history and consciously Prussian in his attitude to the state.” 9
His conservatism made Planck skeptical about the atom, and of particle (rather than wave and continuous field) theories in general. As he wrote
in 1882, “Despite the great success that the atomic theory has so far enjoyed, ultimately it will have to be abandoned in favor of the assumption of
continuous matter.” In one of our planet’s little ironies, Planck and Einstein would share the fate of laying the groundwork for quantum mechanics,
and then both would flinch when it became clear that it undermined the concepts of strict causality and certainty they both worshipped. 10
In 1900, Planck came up with an equation, partly using what he called “a fortuitous guess,” that described the curve of radiation wavelengths at
each temperature. In doing so he accepted that Boltzmann’s statistical methods, which he had resisted, were correct after all. But the equation had
an odd feature: it required the use of a constant, which was an unexplained tiny quantity (approximately 6.62607 x 10 –34 joule-seconds), that
needed to be included for it to come out right. It was soon dubbed Planck’s constant, h, and is now known as one of the fundamental constants of
nature.
At first Planck had no idea what, if any, physical meaning this mathematical constant had. But then he came up with a theory that, he thought,
applied not to the nature of light itself but to the action that occurred when the light was absorbed or emitted by a piece of matter. He posited that
the surface of anything that was radiating heat and light—such as the walls in a blackbody device—contained “vibrating molecules” or “harmonic
oscillators,” like little vibrating springs. 11 These harmonic oscillators could absorb or emit energy only in the form of discrete packets or bundles.