Piero Martin—
The distance from 112 Mercer Street in Princeton, New Jersey, to the physics department at Lincoln University in Pennsylvania is about 148,000 meters. Put that way, it seems like a very long trek. But if we translate it into 148 kilometers, it is decidedly less imposing. Today, Google Maps informs us that, by car, the drive takes an hour and forty minutes, but in 1946 the trip was much more daunting, especially if the person traveling was in their seventies and had health problems. Considering that the reason for the trip was the conferral of an honorary degree—the kind of event that Albert Einstein did not find appealing, in view of the customary pomp and circumstance—it would not have been strange had the father of the theory of relativity declined the invitation. Lincoln, at the time, was a tiny university with an enrollment of just over 250 students.
Nevertheless, Professor Einstein accepted, and gladly so. Because—and these are his exact words, “That visit on May 3, 1946, was for a worthy cause”—Lincoln University’s notoriety belied its small size. It was the first American university to confer a college degree on an African American student. Founded in 1854, it was nicknamed the Black Princeton for the ties between its founders and first faculty members and the much more famous university in New Jersey and because it was a touchstone for African American university students.
In the post–World War II years, racial segregation still plagued the Black community. Although the great majority of white Americans stubbornly refused to recognize the problem, the voice of Albert Einstein rang out loud and clear. Already in 1937, his attitude was unmistakable. He had offered hospitality to Marian Anderson, one of the most famous opera singers of the twentieth century, when she came to Princeton to sing and was denied a room in a local hotel because of the color of her skin. In 1946, in an article for the magazine Pageant—read primarily by a white audience—Einstein had this to say about segregation: “The more I feel an American, the more this situation pains me,” adding, “I can escape the feeling of complicity in it only by speaking out.” On that May 3, the Nobel Prize winner—whose emaciated face and simple ways, as a student at the time recalls, made him look almost like a figure out of the Bible—attended the ceremony at Lincoln University and gave a thank-you speech that would become famous. He spoke harshly against racism and racial segregation, calling it, “not a disease of colored people, but a disease of white people. I do not intend to be quiet about it.”
It would take another nine years before the few meters that separate the front of the bus from the back of the bus—the former reserved for whites and the latter for Blacks—would mark the beginning of the modern civil rights movement, thanks to the courage of Rosa Parks, who refused to walk them. That day was December 1, 1955, and Einstein did not get to see it. He died on April 18 of that year, having played the leading role in one of the greatest revolutions of modern physics. With his theory of relativity, Einstein had reshaped not only his own discipline but the whole of human knowledge. He inspired, right up to the present, the recipients of a long series of Nobel Prizes for research originating from his theory (for which, irony of ironies, he himself was not awarded the Nobel) and became a reference point for artists, philosophers, and intellectuals, as well as a pop icon of physics.
It is only natural, therefore, that Einstein’s revolution has made itself felt strongly also with regards to units of measurement. The theory of relativity describes not a specific phenomenon but rather the environment in which all physical phenomena take place: space- time. The theory does not merely write one part of the big story that nature tells; it establishes the general rules for storytelling. Relativity is a theory about space and time, and as such, it takes precedence over all the others, which must be consistent with it.
For millennia, humanity has attempted to create for itself a global and universal system of units of measurement in order to describe and understand the world and the nature that surrounds us; a system that transcends borders and sovereignties and belongs to everyone. It is not surprising that the theory of relativity has become a milestone on the way toward the universalization of the meter, the unit with which we begin in this chapter our journey of discovery of the measures of the world.
The name meter itself symbolizes the principle of measurement, both for its etymology—from the Greek μέτρον (metron, measure)—and for having lent its name to the first international treaty on units of measure, the Metre Convention, signed in Paris by seventeen nations in 1875. This was an event that rarely appears in history books but that established a first firm foothold in the millennia-long march that started at the dawn of civilization.
From The Seven Measures of the World by Piero Martin and translated by Gregory Conti. Published by Yale University Press in 2024. Reproduced with permission.
Piero Martin is professor of experimental physics at the University of Padua and a science writer. He carries out research on thermonuclear fusion and is chief physicist of the international DTT fusion experiment. He lives in Venice, Italy. Gregory Conti has translated over twenty-five books of fiction, nonfiction, and poetry. He lives in Perugia, Italy.