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By John S. Rigden
When the editors of Time magazine selected Albert Einstein as the person of the 20th century, they explicitly acknowledged his greatness. Today, 50 years after his death, Einstein commands a unique place in contemporary minds: "He's no Norman Einstein, but" …said a television announcer commenting on a smart NFL player or "He's no Einstein, but" …say proud parents as they boast of their prodigy's intelligence. There are many smart people, but it is always Einstein that is held up as the standard. Why? Why the physicist, Einstein?
In his autobiography, Einstein said, "The essential in …a man of my type lies precisely in what he thinks and how he thinks…" We know what the physicist Einstein thought and how he thought because it is in the historical record. The "what" and "how" cannot be over emphasized; however, they provide only part of the answer as to why Einstein occupies such a special place in contemporary culture. Einstein is special for two additional reasons: because of who we are as homo sapiens and because physics itself connects in a cogent way with the human species.
Einstein's accomplishment in 1905 has no equal. In six months, from March 17 to September 26, Einstein wrote five papers. The fundamental nature of these papers implicitly reveals how Einstein approached his physics: "I want to know how God created this world. I want to know His thoughts, the rest are details," said Einstein in his autobiography. "God's thoughts" are not trivial and Einstein's 1905 papers were so basic that they shifted the tectonic footings that underlay physics and put a new face on Nature.
Einstein's March paper confronted the affirmed physical fact that light leaves its source and spreads through the surrounding space as a continuous wave. Einstein challenged this view as he built a powerful case to support his contention that light was not continuous, but consisted of individual, discrete, localized particles. The March paper was the only 1905 paper that Einstein himself called "revolutionary." Indeed, physicists were so repelled by Einstein's particle notion that they totally rejected it for 18 years. Today, Einstein's light particle, named the photon in 1926, is built into the foundation of physics.
Einstein's April and May papers were closely connected. The first was Einstein's doctoral dissertation and led directly to his May paper. Both papers focused on particles in a liquid. In his dissertation, the particles are sugar molecules and Einstein opened the way to determine their size. This was at a time when the reality of atoms was still debated. The dissertation is different from Einstein's other papers in that it has many practical applications, from cement to cow's milk, and is one of Einstein's most cited papers.
In the April paper, the particles are pollen suspended in water. For decades, pollen particles were observed to move throughout the liquid in a random, zigzag fashion. There was no explanation for this motion until Einstein showed that water molecules could depart from their average behavior, unite together, and bombard a pollen particle such that the zigzag motion was the result. This paper turned the last atomic skeptics into atomic believers: with only a ruler and a stopwatch, one could confirm Einstein's theory and observe incontrovertible evidence for atoms.
Einstein's June paper is one of the great papers in the history of physics. In this paper, Einstein presented his Special Theory of Relativity. Starting from two simple axiomatic statements, Einstein transformed our understanding of the two most basic concepts of physics: space and time. The June paper is a masterpiece.
The September paper was a logical extension of Einstein's June paper. In this paper, Einstein showed that two attributes of Nature thatseemed totally different are in fact the same thing. The most famous equation of physics, E=mc2, came from the September paper and with that energy and mass became one.
This is what Einstein did in 1905, by means of pure reason, at the age of 26. While he never had another year like 1905, he did have a long and fruitful career. His single greatest paper, "The Foundation of the General Theory of Relativity, came in 1916. Einstein's papers rank with the greatest in the history of physics; however, the question remains: Why is Einstein, the physicist, the standard of greatness?
As homo sapiens, we are distinguished by our large brain. Humans are the thinking animal. Since the 18th-century Enlightenment, two ideas have become deeply embedded in the minds of western humans.The first idea, coming out of Isaac Newton's work, is that physical laws determine the behavior of Nature.
Nature is not capricious; it is lawlike. The second idea, coming out of John Locke, is that reason is the means to discover Nature's laws. When Einstein divines the laws of Nature by the power of pure reason, he confirms deep-seated human beliefs about the lawfulness of Nature and about the awesome power of human reason. As the thinking animal, humans are drawn to Einstein because, consciously or unconsciously, we share vicariously in Einstein's accomplishments.
Einstein is also special because he was a physicist. In physics, more than other science, the power of pure reason can be convincingly exhibited. Einstein created theories that required new and uncomfortable ways of thinking.But as a physicist, Einstein did more: he used his novel theories to make detailed, quantitative predictions of never-observed phenomena.
When his prediction put at issue a direct product of "God's thought" such as his prediction about the nature of space, the stuff of great import as well as high drama was in the making. In Einstein's General Theory of Relativity, a massive object influences neighboring space by imposing a shape upon it. As a result of this, Einstein recognized that as light passed the Sun, its path would deviate very slightly. How slightly? Einstein predicted that light's path would deviate by 1.75 seconds of arc (in one degree there are 3,600 seconds of arc).
When the Great War ended in 1918, people were emotionally exhausted and they longed for a world that made sense. Einstein's prediction was tested by Arthur Eddington when he measured the deviation of starlight as it passed the darkened Sun during a total eclipse. He measured the light's deviation to be 1.98 arc seconds, thereby confirming Einstein's prediction. Einstein predicted, Eddington confirmed, and people all over the world were comforted to know that "all is right with the world." Einstein became a world celebrity.
Einstein gives all people a sense of pride because he is one of us. He is special because, through his physics, he dramatically displays the essence of both his and our natures. That is why Einstein is the standard of greatness.
John Rigden, of Washington University in St. Louis, is the author most recently of Einstein 1905: The Standard of Greatness, Harvard University Press (2005).
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