Einstein: His Life and Universe
Page 86
* For clarity, I refer to the boy by both of his given names, Hans Albert, although his father invariably referred to him simply as Albert. At one point, Einstein wrote a letter to his son and signed it “Albert” instead of “Papa.” In his next letter, he awkwardly began, “The explanation for the curious signature on my last letter is that, in my absentmindedness, instead of signing my own name, I frequently sign for the person to whom the letter is addressed” (Einstein to Hans Albert Einstein, March 11 and 16, 1916).
* Einstein’s salary after tax was 13,000 marks. Inflation was beginning to set in, and the value of the German mark had fallen from 24 cents in 1914 to 19 cents in January 1918. One mark at the time would buy two dozen eggs or four loaves of bread. (A year later, the mark would be worth only 12 cents, and when hyperinflation began to rage in January 1920 only 2 cents.) Mari’s stipend of 6,000 marks in January 1918 was thus worth about $1,140, or just under $15,000 in inflation-adjusted 2006 dollars. His proposal was to increase this by 50 percent.
* Chapter 14 describes Einstein’s revision of this view in a 1920 lecture in Leiden.
* See chapter 14 for Einstein’s decision to renounce the term when he discovered the universe was expanding.
† Described in chapter 14.
* The word Einstein used was Stammesgenossen. Although Stamm generally means tribe, that translation can have some racial overtones. Some Einstein scholars have said that translations such as “kindred” or “clan” or “lineage” might be clearer.
* I have used the translation preferred by Abraham Pais. Einstein’s words in German were, “Raffiniert ist der Herr Gott, aber boshaft ist er nicht.”
* Governor Channing Cox had been thrust a version of the test earlier that week, and his first three responses were: Where does shellac come from? “From a can.” What is a monsoon? “A funny-sounding word.” Where do we get prunes? “Breakfast.”
* Robert Andrews Millikan would win the Nobel Prize the following year, 1923, for experimental work on the photoelectric effect he had done at the University of Chicago. By then he had become director of the physics lab at the California Institute of Technology, and in the early 1930s he would bring Einstein there as a visiting scientist.
* See page 119 for Newton’s thought experiment about whether water rotating in a bucket in empty space would be subject to inertial pressure and thus press against the sides of the bucket. See page 251 for Einstein’s 1916 view, which he was now revising, that an empty universe would have no inertia or fabric of spacetime.
* The de Broglie wavelength of a baseball thrown at 90 mph would be about 10–34 meters, incredibly smaller than the size of an atom or even a proton, so infinitessimal as to be unobservable.
* In 1995, Bose-Einstein condensation was finally achieved experimentally by Eric A. Cornell, Wolfgang Ketterle, and Carl E. Wieman, who were awarded the 2001 Nobel Prize for this work.
* From his 1905 special relativity paper: “It is well known that Maxwell’s electrodynamics—as usually understood now—when applied to moving bodies leads to asymmetries that do not seem inherent in the phenomena. Take, for example, the electrodynamic interaction between a magnet and a conductor.” From the 1905 light quanta paper: “A profound formal difference exists between the theories that physicists have formed about gases and other ponderable bodies, and Maxwell’s theory of electromagnetic processes in so-called empty space.”
* “To be is to be perceived,” meaning that it makes no sense to say that unperceived things—most famously Berkeley’s example of trees in a forest “and no body by to perceive them”—actually exist (George Berkeley, Principles of Human Knowledge, section 23).
* As Eddington showed, the cosmological term probably would not have worked even if the universe had turned out to be static. Because it required such a delicate balance, any small disturbance would have caused a runaway expansion or contraction of the universe.
* The pacifists assumed that no other explanation was needed, but some contemporary accounts somehow thought the buttons referred to 2 percent beer.
* There are two related concepts that Einstein uses.Separability means that different particles or systems that occupy different regions in space have an independent reality; locality means that an action involving one of these particles or systems cannot influence a particle or system in another part of space unless something travels the distance between them, a process limited by the speed of light.
* An aneurysm is the ballooning or dilation of a blood vessel, as if it were blistering. The abdominal aorta is one of the large arteries from the heart, in the region between the diaphragm and the abdomen.