Skip to comments.The Patent Clerk's Legacy [Einstein]
Posted on 11/22/2004 7:54:18 AM PST by PatrickHenry
In 1905 the musings of a functionary in the Swiss patent office changed the world forever. His intellectual bequest remains for a new generation of physicists vying to concoct a theory of everything.
Albert Einstein looms over 20th-century physics as its defining, emblematic figure. His work altered forever the way we view the natural world. "Newton, please forgive me," Einstein begged as relativity theory wholly obliterated the absolutes of time and space that the reigning arbiter of all things physical had embraced more than two centuries earlier.
With little more to show than a rejected doctoral thesis from a few years before, this 26-year-old patent clerk, who practiced physics in his spare time and on the sly at work, declared brashly that the physicists of his day were "out of [their] depth" and went on to prove it. Besides special and general relativity, his work helped to launch quantum mechanics and modern statistical mechanics. Chemistry and biotechnology owe a debt to studies by Einstein that supplied evidence of the existence of molecules and the ways they behave.
What is even more amazing is that he purveyed many of these insights through a series of papers that appeared during a single miraculous year, 1905. No other comparably fertile period for individual scientific accomplishment can be found except during 1665 and 1666, the original annus mirabilis, when Isaac Newton, confined to his country home to escape the plague, started to lay the basis for the calculus, his law of gravitation and his theory of colors. The international physics community has set aside 2005 as the World Year of Physics as a tribute to Einstein's centennial.
Scientists in many realms of physics and engineering spent the 20th century testing, realizing and applying the ideas falling out of Einstein's work. As everybody knows, Einstein's E = mc2 formula was a key to the atomic bomb--and all the history that sprang from it. Einstein's explanation of the photoelectric effect underpinned technologies ranging from photodiodes to television camera tubes [see "Everyday Einstein," by Philip Yam]. A hundred years later technologists are still finding new ways to harvest novel inventions from Einstein's theories.
One mark of genius relates to the length of time needed to fully explore, through experimentation, the implications of a new theory. In that sense, Einstein is still going strong. A recently launched space probe will examine various predictions of general relativity. But physicists are not waiting until the answers are all in before asking what comes next. Much of the most exciting work in physics now has the more ambitious aim of going beyond Einstein--of transcending his ideas and achieving a task akin to the one to which he devoted the last 30 years of his life, right to his deathbed, without success.
It is clear that general relativity and particle physics form an incomplete description of physics, because the latter is fundamentally quantum-mechanical, and general relativity and the quantum go together like oil and water. Despite decades of effort, Einstein was never able to find a theoretical framework for uniting relativity and electromagnetism. He had hoped to formulate a physics based on certitudes, not the probabilities and acausal realities of quantum mechanics--just the things that had turned him away from a field he helped to found. A current generation of scientists is laboring on their own theories of everything, armed with a much more complete description of fundamental physical forces than Einstein used, while approaching the challenge without a preexisting bias against quantum mechanics. The rewards for succeeding in this endeavor? For the physicist who prevails, they might include immortality of the kind attached to the names Einstein and Newton. For the rest of us, they may provide a glimpse into nature and new technologies as incomprehensible to us now as black holes and quantum computers would have been 100 years ago.
To go beyond Einstein, one must first understand the totality of his accomplishments. In the spring of 1905 the young "patent slave," as Einstein called himself, sent a letter to his friend Conrad Habicht to tell him that he had some "inconsequential babble," a reference to a series of papers that he was going to send him. The only one of the bunch he called "very revolutionary" did not deal with relativity, but it did gain him the 1921 Nobel Prize, awarded in 1922. "On a Heuristic Point of View Concerning the Production and Transformation of Light," completed in March, expropriates and extends Max Planck's idea of quanta--that energy from hot objects can be emitted or absorbed only in certain discrete bundles.
In the paper, one of five major offerings during 1905, Einstein applied the concept of quanta to explain the photoelectric effect, how a piece of metal charged with static electricity would discharge electrons when exposed to light. He suggested that the beam of light is made up of particles, later known as photons, thus contradicting the prevailing notion that light was only wavelike. The paper, published in June in Annalen der Physik, paved the way for the acceptance of the dual nature of light as both particle and wave, which became a foundation of quantum mechanics. The photoelectric effect went on to become the basis for various technologies.
At that time, Einstein still had not yet received a doctorate. The University of Zurich had rejected a thesis he had submitted in 1901--an unexceptional work on the kinetic theory of gases. Einstein had all but discarded the idea of undergoing what he called the "comedy" of getting his advanced degree. But he decided to try again in 1905. According to his sister, Maja, he first submitted his paper on special relativity, but the university found it a "little uncanny." He then picked "A New Determination of Molecular Dimensions," which he finished on April 30 and which was accepted in July. It was reportedly inspired by a conversation over tea with his best friend, Michele Besso, in which Einstein mused about relating the viscosity of the liquid to the size of the dissolved sugar molecules. By considering a collection of such molecules, Einstein derived a mathematical term that measured the speed of diffusion. It was then possible to elicit the size of the sugar molecules by contemplating the diffusion coefficient and the viscosity of the solution.
A few days after completing this article, Einstein finished a related paper that was also intended to provide a guarantee of "the existence of atoms of definite size"--atoms were a still controversial idea in some circles. "On the Motion of Small Particles Suspended in Liquids at Rest Required by the Molecular-Kinetic Theory of Heat," published in July in Annalen, supplied a prediction of the number and mass of molecules in a given volume of liquid--and how these molecules would flit around. The erratic movements were known as Brownian motion, after the observation by Robert Brown in the early 19th century of the irregular zigs and zags of particles inside pollen grains in water. Einstein suggested that the movements of the water molecules would be so great that they would jostle suspended particles, a dance that could be witnessed under a microscope. This paper, an important contribution to modern statistical mechanics, derived methods that can be used to simulate the behavior of airborne pollutants or the ways in which the stock market fluctuates [see "Atomic Spin-offs for the 21st Century," by W. Wayt Gibbs].
The next paper, completed in late June, was entitled "On the Electrodynamics of Moving Bodies." Relativity predated Einstein by hundreds of years. In 1632 Galileo suggested that all physical laws are the same regardless of your state of motion, as long as the velocity at which you cruise along does not change: viewed from the deck of a steadily moving ship, a rock dropped from the mast falls straight down, the same as it would if the ship were at rest. That relativity principle held for the laws of mechanics put forward by Newton in the mid-17th century. But this tidiness was upset in the late 19th century with the emergence of electromagnetism. Because the equations of James Clerk Maxwell showed that electromagnetic radiation moves through space in waves, physicists assumed that it coursed through a medium, the ether, the same way that sound waves do through air. Maxwell demonstrated that light and other electromagnetic waves race along at 300 million meters per second in a vacuum relative to the frame of reference of someone at rest in the ether. In an ether world, however, relativity would not hold for light. As soon as you budge from a state of rest, the speed of light would not measure 300 million meters per second anymore. Experimentalists, however, could never find the expected differences for moving objects. The speed of light always remained the same.
It was this inability to reconcile electromagnetism and the rest of physics that Einstein addressed. A scientist with a deep sense of aesthetics, he could not abide that the relativity principle did not account for electromagnetism as it did for Newtonian mechanics. The 1905 paper on special relativity, published in September of that year, reaffirms the principle for all of physics by applying it to electromagnetism and also establishes that the speed of light is a constant. While resolving the relativity paradox, the paper presented a new one, which strains our commonsense intuition of how things work: the speed of light remains the same whether someone is sitting in a rocking chair on the front porch or zooming along steadily in a futuristic spacecraft approaching light speed.
This constancy for light wreaked havoc with our idea of time and space as unchanging absolutes. Velocity boils down to distance divided by time. For light speed to remain unchanging on its side of the equation, both distance (length) and time had to be altered on the other when an observer in one frame of reference (the rocking chair) is watching someone move in another (astronauts in a spacecraft). Specifically, the man in a rocking chair will perceive time passing more slowly for the astronauts overhead. To him, the spacecraft will also shorten in the direction of motion.
If the rocking-chair man could somehow measure the mass of the astronauts as the spacecraft coursed along, he would also notice that they had gained mass since before its liftoff. The fifth and last paper of Einstein's miraculous year, published in November in Annalen, served as an addendum to his special relativity opus. In it, he stated that the "mass of a body is a measure of its energy content," a concept that Einstein rephrased in 1907 as the most famous scientific equation of all time. E = mc2 also applies to kinetic energy, the energy of motion. The faster the spaceship goes relative to the man in the rocking chair, the greater its kinetic energy and the greater its mass, making it increasingly difficult to accelerate. As the ship approaches the speed of light, the increments of energy needed to go faster are so large that additional acceleration becomes more and more onerous, one reason that a faster-than-light rocket ship remains only within the realm of science fiction.
After 1905, the best was yet to come. As an intellectual achievement, the general theory of relativity, published in 1916, outshines anything that Einstein (or any physicist except maybe Newton) had done before or since then [see "Einstein and Newton: Genius Compared," by Alan Lightman]. Mathematician Henri Poincaré almost beat Einstein to special relativity but refused to take the final but vital step of discarding the ether. The special theory had reconciled disparities in Newtonian mechanics and Maxwellian electromagnetism, but only for bodies in uniform motion, those traveling at constant speeds in straight lines. A general relativity theory was needed for the real world in which bodies change speed and direction--in other words, it would have to take into account the effects of acceleration, including that most universal of accelerations, gravity. Newton saw gravity as a force acting instantaneously over long distances, but Einstein reimagined it as an intrinsic property of space and time. A star or any massive body curves Einstein's space and time around it. Then planets move along the curved pathways in the spacetime continuum.
"The idea that mass warps spacetime and that warped spacetime tells mass how to move is pure genius," says Michael Shara, chair of the department of astrophysics at the American Museum of Natural History and curator of a recent exhibit on Einstein. "Physicists would eventually have discovered general relativistic effects on the basis of satellite and pulsar measurements but probably not until late in the 20th century. Even then, Einstein's elegant geometrical description of gravity might not have been fully replicated."
Soon after his general relativity paper, a 1919 experiment observed the sun's gravitational field deflecting rays of starlight passing through it during a solar eclipse, a prediction of the general theory. The evidence for general relativity made Einstein an instant media star, even though many in the crowds that thronged to see him would be hard-pressed to explain what the scientist had achieved. Apocryphally, Einstein was quoted as saying that only 12 people in the world understood relativity. Even if he really said it, the tiny number is a bit of an exaggeration. A devoted pack of Einstein aficionados emerged immediately. Scientific American even sponsored a contest, drawing hundreds of entrants for a $5,000 prize for the most understandable explanation of relativity. Einstein joked that he was the only one in his circle of friends not to participate. "I don't believe I could do it," he quipped. (See "A Century of Einstein," by Daniel C. Schlenoff)
From 1916 to 1925, Einstein made new contributions to quantum theory, including the work on stimulated emission of radiation that eventually resulted in the laser. But he became disenchanted with quantum mechanics as it embraced statistical probabilities instead of causal explanations to delineate what was happening in the world of subatomic particles. For the latter part of his life, until his death in 1955, Einstein concentrated on a unified field theory, which would not only reveal gravitational and electromagnetic fields as two aspects of the same thing but also explain the existence of elementary particles and constants such as the electron's charge or the speed of light.
These labors proved to be a dead end--in part because Einstein rejected the new turn that quantum physics had taken and in part because two fundamental nuclear forces (the strong and the weak) were not well understood until years after his death. "Even devoted admirers of Einstein would not dispute that the progress of physics would not have suffered unduly if the indisputably greatest scientist among them had spent the final three decades of his life--roughly from 1926 on--sailing," noted Albrecht Fölsing in a 1993 biography, referring to one of Einstein's hobbies. Others are more charitable. The physicist may simply have been ahead of his time: "The ongoing quest for a theory of everything is Einstein's most significant legacy to science," observes Ze'ev Rosenkranz, former curator of the Einstein papers.
That search still serves as the main focus of a prominent sector of the theoretical physics community. Physicists continue to marshal sophisticated mathematics to explain all the forces of nature. They have even picked up on the labors of Theodor Kaluza and Oskar Klein, extending the two men's thinking about a five-dimensional universe, a proposal that intrigued Einstein in his own search for a unified theory [see "The String Theory Landscape," by Raphael Bousso and Joseph Polchinski]. Separately, the ongoing search for violations of relativity may provide one of the best routes to experimental hints about how to meld quantum mechanics and gravity into a single seamless theory [see "The Search for Relativity Violations," by Alan Kostelecký, on page 92]. And the revival of Einstein's cosmological constant, a form of energy that creates a repulsive force, remains at the forefront of the cosmology that is trying to find the keys to "dark energy" [see "A Cosmic Conundrum," by Lawrence M. Krauss and Michael S. Turner].
If his search for a unified theory was premature, Einstein experienced more success in later life by using his fame to advocate causes about which he felt passionately. He had difficulty understanding why the rest of the world was so fascinated by relativity. It described the physical world and had nothing to do with subjective psychological viewpoints of time and space purveyed by cultural relativists. "I never understood," he commented, "why the theory of relativity with its concepts and problems so far removed from practical life should for so long have met with a lively, or indeed passionate, resonance among broad circles of the public."
His renown, though, did let him speak out on pacifism, world government, and the need to counter the Nazis' efforts to develop a nuclear bomb. The same longing that took him from the theory of relativity--a joining of Newtonian mechanics and Maxwellian electromagnetism--to an all-encompassing field theory carried over into the rest of his life. "As in his science, Einstein also lived under the compulsion to unify -- in his politics, in his social ideals, even in his everyday behavior," acknowledges Gerald Holton, a preeminent Einstein scholar at Harvard University.
If Einstein were suddenly to return through some magical post-mortem warping of time and space, he might be less than wowed by the worldwide celebrations of his Year of Miracles. More interested in ideas than the media circuit, he might well divert from commemorative Year of Physics ceremonies in Jerusalem, Zurich, Berlin or Princeton to consult about the latest efforts to detect the gravity waves postulated by general relativity. And he might then go on to palaver with scientists about results from NASA's Gravity Probe B, which may provide evidence for frame dragging, the relativistic prediction that a rotating massive body, such as Earth, lugs space and time with it.
Certainly he would be intrigued by the revival of his long-discarded cosmological constant as a means of helping to explain why the expansion of the universe is accelerating. He might express fascination at a distance for work on superstrings, branes, M-theory and loop quantum gravity, all attempts to merge quantum mechanics with the gravity packaged in his general relativity. He would undoubtedly be pleased to see that physics is pushing beyond his mark, impelled by the desire he shared to elicit a coherent worldview that explains things starting at the level of subatom and working up to an integral cosmos.
Einstein proposed E=mcsquared. Bwahahahahahaaaa! These eathlings kill me.
Centenial coming up. Can we break the barrier to FTL flight?
WTF?? This is not right.
At some point, I'm going to take my neglected math studies up again. Some of the stuff out there is so mind boggling, I think it is worth the effort to try and understand it better.
Relativity is about gravity. Gravity hasn't yet been successfully unified with the other forces (at least to my knowledge). It's kinda off by itself.
Now THAT should be classically forbidden.
How's this? (I wish I could claim it as my own but another freeper came up with it I've been itching to use it.)
Lethargic thread placemarker.
-relativity limits magnitude -that is all it limits...
And of course, special relativity was the logical outcome of Maxwell' theory of electromagnetism. I had a similar "WTF?" moment reading that passage.