Simply Einstein

Jimena Canales

• Publisher: Simply Charly
• Year: 2021
• ISBN:
  9781943657469
• Topic: Technology & Engineering
• Subtopic: Science & Technology Biographies
• Index: Technology & Engineering

Albert Einstein (1879-1955) was born in Ulm in the German Empire and received his academic teaching diploma from the Swiss Federal Polytechnic School in 1900. Unable to secure a teaching post, he eventually found work in the Swiss Patent Office in Bern, where he began to develop his special theory of relativity. In 1905 (his "miracle year"), he published four revolutionary papers, which came to be recognized as stunning breakthroughs in physics. For the next 25 years, while continuing his research, he taught at several universities in Europe, relocating to the U.S. in 1933, when Adolf Hitler came to power. During World War II, his insights regarding mass-energy equivalence led to the development of the atomic bomb, a practical demonstration of his theories that shook the world. Einstein was horrified that the bomb was used, and he spent the rest of his life warning about the dangers of nuclear weapons and advocating for peace and international cooperation.

In Simply Einstein, Professor Jimena Canales offers the reader a unique perspective on the man who occupies a singular place in the popular imagination. Unlike many Einstein biographies, her book does not glorify the scientist or get lost in esoteric details, but takes pains to present a straightforward, thoroughly readable introduction to the man and his work that shows just how and why an eccentric physicist became a household name.

The universe that Einstein described is the one in which we now live, a world of paradoxes and uncertainty, as well as infinite possibility. For anyone interested in better understanding how this came to be–and in gaining a fuller appreciation of the brilliant, flawed human being who changed everything– Simply Einstein is essential reading.

2

The Three Classic Tests

The Michelson-Morley experiment had not sufficed to convince his colleagues of the need to adopt his theory. What else could he do? How many other experiments would he need to convince his peers to espouse it? For more than a decade, Einstein accumulated evidence in its favor and was able to add three more pieces of evidence to buttress its momentous claims.

Einstein was influenced by success stories of famous discoveries that had established the prestige of science from the 19th century onwards. He imitated those models, working hard to show how his theory could predict what others could not.

To this day, the value of science is often credited to its predictive powers. This view reached prominence in the 1800s when one stunning discovery—of the planet Neptune—captivated the attention of the public and the popular press. The classic story of Neptune’s discovery dated to 1845, when the French astronomer Urbain Le Verrier noticed that certain calculations of the solar system pointed towards the probable existence of a planet that had yet to be observed. His model turned out to be so accurate that when a German astronomer turned his telescope to the part of the sky where Le Verrier believed the planet should be, he was able to observe it. Le Verrier’s discovery soon became a paradigmatic example that helped popularize the idea that theoretical science and abstract mathematics could reveal the existence of previously unknown phenomena. This portrayal was mostly due to the astronomer François Arago, known for having announced the invention of photography a few years earlier. Arago grandiosely claimed that Le Verrier had predicted the existence of a new planet “with the tip of his pen.” Not everyone believed Arago’s retelling of the discovery. Many of those who studied Le Verrier’s work carefully started to dissent from this standard narrative. Insiders noted that the planet had already been seen by others (in Britain) and that Le Verrier simply stole the show (with Arago’s help) from other scientists.

Prediction on the sole basis of pencil-and-paper calculations were a high standard for science at that time. Einstein aimed that high.

The possibility of creating predictions from abstract mathematics was only one of science’s many virtues. Its champions often turned to another reason to defend it. Science could be used as a method for determining unambiguous truths in the face of debate. Scientific experiments, in this view, could serve as blind judges in bitter duels, as final and fair arbiters of truth in the face of conflict, offering results not swayed by subjective opinion, human interests, or politics. Einstein admired this aspect of science as well, which became popular thanks to Arago.

The model of science as a judge became firmly established during one of the most famous scientific experiments of all time. It pertained to the topic of light. Was light made of waves or particles? Arago orchestrated a kind of duel between two scientists to get at the truth of the matter. One of them was Armand Fizeau, who argued in favor of the “emission theory” of light which considered it as made up of particles. The other one was Léon Foucault, who believed it was wavelike. Arago arranged a carefully planned contest between them in 1850. After observing the results, Foucault argued that his own hypothesis won. As with the case of Le Verrier’s discovery of Neptune, not everyone was convinced about who the real winner was. Scientists would continue to investigate cases were light appeared particulate as well as wavelike (today, the consensus is that it is both). Regardless of the outcome or of the finer details around these discoveries and experiments, these 19th-century models of science became the gold standard for the profession for years to come.

The way “The Foundation of the General Theory of Relativity” was written conformed to a particular model of scientific discovery. It began by stating a bold hypothesis that led to observations, often referred to as “predictions,” which would count as tests in its favor. All three “tests” proposed by Einstein had pros and cons when it came to their power to buttress the theory. One produced results that had been known for a long time. It was therefore a retrodiction rather than a prediction, pertaining to a widely known observation that had long puzzled scientists. The other two observations were mostly expected, yet they dealt with phenomena that were hard to ascertain and difficult to repeat. One of them—revealing the bending of starlight—required complicated measurements during rare solar eclipses. It would finally make Einstein and his theory world-famous.

The first of these tests is known as the advance of the perihelion of Mercury, a term that refers to the distance of the planet Mercury to the Sun when it is closest to it. Scientists had known since the mid-19th century that if they used the current laws of physics to calculate Mercury’s perihelion and compared the result to actual observations, they were off by 43 seconds of arc per century. The difference had bothered astronomers for years. One of the benefits of Einstein’s new theory was that it produced results that matched perfectly with preexisting observations. Yet Einstein’s explanation of the discrepancy failed to get much attention since it did not reveal anything new, unknown or unexpected. Quite the contrary.

The second test was even less dramatic. It involved measuring changes in the frequency of light waves, that is, in the distance between crests and troughs which, in the case of visible light, give it its particular color. Einstein proposed that light waves would change frequency in the presence of large masses, moving towards the red side of the spectrum (called a redshift) as they moved away from them and towards the blue when closer. Since the mid-19th century, astronomers had surmised that light waves might be subject to effects similar to those already observed with sound waves, where they grow longer as they travel away from the receiving instrument and shorter when going towards it. Why would it be any different for light waves? Additional causes—not only those of waves moving towards or away from us—might produce similar shifts.

The final test was the bending of starlight in the vicinity of a large mass. Large masses created tremendous effects around them, traditionally ascribed to the force of gravity. Could masses affect light? Could they make it bend?

Such curvature was hardly perceptible. Why was Einstein so concerned with a minuscule shift showing light bending? Why would other scientists, including astronomers, care so much about testing this aspect of his theory and direct considerable resources to that end?

Testing Einstein’s hypothesis was not easy. One way to test it was to study how starlight was affected by the mass of the Sun. Normally, the stars around the Sun were invisible because of the brightness of sunlight. But when the Sun was covered by the Moon, the stars in almost the same line of sight as the Sun became momentarily visible. An eclipse gave scientists just enough time to snap photographs and compare them with the results predicted theoretically. Those in charge of the project hoped to show that the location of the stars in the sky was off by a very slight amount compared to the location predicted by old theories. They hoped they would appear “shifted” due to the curved path of starlight around the Sun.

The change or “shift” the scientists hoped to detect on the photographic plates was incredibly small, about 1/2500th of the apparent diameter of the Sun (approximately 1/3600 of a degree). Never in the entire history of science had such a small difference received so much attention.

Who knew?

The exact way in which light traveled across space impinged on technological and scientific questions of great importance at the time. With telegraphy, the path of electromagnetic wave transmission naturally followed the path of the wire. What path would it take when no wires were involved? During his years at the office, patents pertaining to wireless telegraphy were particularly sought after and subject to intense litigation as inventors battled over priority claims.

Once researchers discovered that invisible electromagnetic waves could be used to send messages wirelessly, they started to study in greater detail the path these waves took across space. As they progressively increased the distance at which they could transmit messages, they noted that these light waves did not travel in straight lines. Since the Earth curved underneath them, the waves did not exit our atmosphere but wrapped themselves on its surface. This was a stunning and widely-welcomed fact: the possibility that electromagnetic waves could potentially be detected at distant locations in remote corners of the Earth fascinated researchers. Curving waves were perfect for communication on a planet that was not flat.

The idea of curving light waves at first seemed counterintuitive. Since ancient times, lines and rays had been defined by reference to each other. Many of the basic principles of geometry were grounded in such a comparison. When researchers began studying “radio” waves, they chose the term in reference to the Latin word for radius and ray. If rays that had always been represented by straight lines did not travel strictly straight, did the basic principles of geometry need to be rethought and rewritten? What about those of physics? Einstein believed so. What appeared straight to some on a particular path might not be so for others on the outside. Physicists could decide to agree on a particular definition of straight matching perfectly well with our intuitive understanding of the concept in order to rescue traditional concepts of time and space, or they could abandon all these concepts completely.

Communication engineers experimenting with early radio technologies were the first to notice electromagnetic waves wrapping themselves around the globe’s surface. A researcher writing in 1901 in the specialized technical journal London Electrical Review, noted how they “skim or glide over the surface of the earth until further orders” with the consequence that “the curvature of the earth should not affect transmission, and if sufficiently powerful effects are produced, transmission over any distance should be possible.” An electrical engineer from Glasgow explained the following year how “the result of the actual experiment can not agree with the rectilinear propagation of the waves, the curvature of the globe seemingly having no effect, disposes of the straight-line propagation.” Readers were shocked to learn that these waves “bend around the curved surface of the earth through many degrees of arc.” Another expert telegrapher of that era described how engineers had been pleasantly surprised by this discovery. “It was at first thought that this distance would be limited to within a few hundred miles by the curvature of the earth,” until they found out that the electrical “disturbance spread over the whole globe and may be detected at any other part of the surface by a sufficiently sensitive electric wave detector.”

Engineers did not know what or why they bent so. But the fact that they “follow the contour of the earth or ocean” was accepted wisdom by 1900. In the years that followed, more and more researchers studied light paths with increasing precision, trying to develop better-sending stations and receiving antennas, working mostly by trial and error. By the first years of the 20th century, they had succeeded in sending and detecting invisible wireless messages across more than 2500 miles.

Dreams come true and persistent nightmares

When Einstein completed his General Theory in 1916, he eagerly wrote to a close friend to tell him how this theory was the fulfillment of his “boldest dreams.” Yet not everything went smoothly afterwards. A priority dispute soon surfaced.

The leading German mathematician David Hilbert had come up with the same set of field equations at about the same time as Einstein. Many scholars have tried to establish exact priority between Hilbert and Einstein. The consensus is that drawing such a division is nearly impossible, as the two collaborated with each other intensively and shared their work back and forth. Hilbert’s contributions were superior in terms of mathematics; Einstein’s in physics. Einstein was worried. Hilbert responded generously to his colleague’s concern, effectively granting Einstein the credit he sought.

Understanding why Einstein reacted differently from Hilbert when it came to claiming priority highlights the physicist’s views about the worth of his work. Rarely did mathematicians themselves believe so much in the importance of their own discoveries. Under the most common view of their discipline, mathematics was a tool through which scientists could know the universe. They manipulated symbolic abstractions that corresponded in some ways to concrete and measurable phenomena. In Einstein’s opinion, mathematics was much more—it was a reflection of the universe itself. While Hilbert’s and Einstein’s equations were nearly identical, Einstein went further than his colleague in the manner that he interpreted them. He imbued these results with much greater significance.

Einstein’s biggest gamble, and one of the reasons he stood head and shoulders above his peers, pertained to how he conceived of the relation between science, mathematics, and truth.

Standing on the shoulders of giants

Einstein’s reaction to Hilbert’s work vis-à-vis General Relativity shared similarities with how he responded to two scientists who had been the first pioneers in these new fields of physics. These two men were some of the most respected scientists in Europe, inaugurating work on the topics that became central to Einstein long before he even first heard about them. They first showered attention on the Michelson-Morley experiment and on the problem of Mercury’s perihelion, described newly discovered properties of light, electricity, photons, and electrons, wrote new equations for them, and studied and explored the relation between their masses, energies, and inertia.

One of them was the formidable Henri Poincaré, a polymath from France recognized as a mathematical genius from a young age. The other one was Hendrik Lorentz, a prodigy from the Netherlands who became professor of physics at the young age of twenty-four and who discovered the relativity equations which Einstein used. Poincaré and Lorentz formed a formidable team, working on such similar topics that one of their colleagues described the latter simply as “the Dutch Poincaré.” Neither thought Michelson’s result was wrong—on the contrary, both fully accepted his research and developed brilliant explanations for it. Einstein would become embroiled in bitter priority disputes with them.

Poincaré moved easily between public service roles and fundamental research. He was a sought-after expert on mining, transportation, and telecommunications industries, contributing across applied and theoretical sciences in engineering, mathematics, physics, astronomy, and philosophy. He was an evocative lecturer and a widely-read author. He could not be more different from Einstein. Older and bourgeois, Poincaré moved in the dominant conservative Catholic circles of Paris. He came from an elite family accustomed to occupying top-level appointments in prestigious state institutions. He could count a President of the Republic as one of his cousins.

Einstein read Poincaré’s work avidly. While working at the patent office, he organized a small book club with two of his closest friends. They called it the Olympia Akademie. Their reading list included a book called Science and Hypothesis by Poincaré. The three discussed it over a simple dinner (which typically consisted of sausage, Gruyère cheese, fruit, a small jar of honey, and tea). One of his friends in the group recalled how the book “profoundly impressed us and kept us breathless for many weeks.”

Einstein had more in common with Lorentz. The two were in general agreement about some of the most pressing political controversies of their time and saw eye to eye on issues pertaining to the horrors of war, the politicization, and militarization of science, the fate of German scientists who were boycotted in its aftermath, among other topics. Their relationship, although always cordial, was nonetheless extremely tense at certain moments.

Einstein’s first paper on relativity theory mostly fell on deaf ears; Lorentz’s work, in contrast, attracted more and more attention. One of the few notes that did mention Einstein’s drily included the caveat that it “leads to results whi...