The fine-structure constant

Arnold Sommerfeld

One of the latest scientific advances of 2020 was a new, more precise measurement of the fine-structure constant. The last value officially accepted in 2018 by the Committee for Data on Science and Technology (CODATA) is equal to 1/137.035999084. The value obtained in December 2020 is equal to 1/137.035999206. It will be seen that the difference with the previous value is very small and affects only the seventh decimal place.

But what is the fine-structure constant? It's a dimensionless constant, defined by the following formula:

Dating the Turin Shroud

Comparison of positive (left)
and negative (right) photos

The Shroud of Turin (or Sindone, from the Greek σινδών, shroud) is traditionally thought to be the shroud that covered the body of Christ during the three days that he was buried between his death on the cross and his resurrection. The documented part of its history begins in 1357, when it was exhibited for the first time in Lirey (France). In 1453 it was sold to the Duke of Savoy. In 1532 it was damaged in a fire, and in 1578 was transferred to Turin, where it is located today. Although the Catholic Church allows its veneration, it has never pronounced either in favor or against the authenticity of the Shroud, which from the beginning was the subject of controversy, as some claimed it was a contemporary painting, while others considered it authentic.

In 1898 the Shroud was photographed for the first time and the image was found to be much sharper on negatives than on positives, so the original image appears to be roughly equivalent to a photographic negative.

Is there a crisis in theoretical physics?

Nicolaus Copernicus

Physics has been, for the last seven centuries, the queen of sciences: its object is the study of the lowest-level of reality; its most akin to mathematics; it has seen happen the highest number of new, spectacular and revolutionary theories and discoveries. Let's see a few of them:

• 13th century: Roger Bacon studies reflection, refraction, spherical aberration and the use of lenses to correct vision defects. He also suggests the possibility of building telescopes, microscopes, and flying vehicles.
• 14^th century: Jean Buridan, Nicolás Oresme, Albert of Saxony and the calculators of Merton College revolutionize Mechanics, separating it for the first time from the work of the Greek philosophers, and introducing new concepts such as impetus.
• 16th century: Copernicus proposes replacing Ptolemy's geocentric system by a much simpler heliocentric system. Kepler modifies the theory of Copernicus and discovers the three empirical laws that bear his name.
• 17th century: Galileo perfects the telescope and makes with it astronomical discoveries. He also recapitulates and organizes the mechanical discoveries of the 14th century. Newton revolutionizes physics with the theory of universal gravitation, which unifies terrestrial and celestial mechanics, and makes great advances in optics. Other important physicists of that century are Pascal, Huygens, Boyle, Mariotte, and many more.
• 18th century: Although it's possible to detect a certain slowdown in scientific research, we can mention the Bernoulli brothers, and near the 19th century, Galvani, Volta and Laplace.
• In the 19th century, discoveries in theoretical and experimental physics and the number of professional physicists increased dramatically. Let's mention just a few of the most important: Dalton, Faraday, Ampère, Gauss, Maxwell, Carnot, Lord Kelvin and Boltzmann.

Influence of aesthetic ideas in physics

The Birth of Venus by Botticelli

In a previous post I reviewed the new book in Spanish by Francisco José Soler Gil, entitled The enigma of the natural order. Its third chapter, whose title is Aesthetic ideas in physics, which reproduces a lecture given by the author at the Faculty of Chemistry of the University of Seville, has provided me with matter for this post in my blog.

The influence on physics of aesthetic ideas is very old, perhaps as old as physics. One of its oldest precursors is Pythagoras, who proposed the concept of the harmony of the celestial spheres, according to which the distances between the planets would reproduce harmonious musical intervals.

Mesozoic marine reptiles

Jules Verne

In 1867, Jules Verne published his famous novel Journey to the Center of the Earth, whose protagonists discover an underground ocean at great depth, which they baptize as the Liddenbrock Sea, and witness the fight to the death of two great marine animals: a plesiosaur and an ichthyosaur, supposed descendants of ancestors that sank with the Liddenbrock Sea a hundred million years before and survived down there, protected by the Earth's crust, while their surface congeners became extinct as a result of the impact of the meteorite or comet that put an end to most dinosaurs, although that was not known in Verne’s time. But what were those plesiosaurs and those ichthyosaurs that populated the seas during the Mesozoic, formerly called the Secondary Era?

At the dawn of the age of dinosaurs, the oceans of the Earth were joined in a single sea, Panthalassa, which surrounded the supercontinent Pangaea. In that global ocean, at the beginning of the Triassic period, ichthyosaurs appeared. Since the Jurassic, and during the rest of the Mesozoic, Pangaea gradually fragmented, giving rise to new seas.

The Clock in Strasbourg Cathedral

Clock of Strasbourg Cathedral

One of the most surprising instruments used to measure time is the clock of Strasbourg Cathedral, which contains a mechanical computer, a marvel made up of gears and cogwheels, a pinnacle of the instrumentation of that time, which could be considered comparable to Charles Babbage's Analytical Engine, except that it is not a programmable computing device, but a computing machine built for the specific purpose of calculating time. More details can be found in this article in the journal The Sciences of the New York Academy of Sciences.

The clock is inside the building, rather than at a tower, like those of many other cathedrals. It has a long history, as it dates back since the 14th century, although it was completely rebuilt in the 16th. By the end of the 18th century it stopped working. Legend says that, at the beginning of the 19th century, an orderly who was showing the cathedral to a group of visitors mentioned that the clock had not been working for a long time. Then a boy who was part of the group exclaimed: I will fix it! Forty years later, he did. That child would have been Jean-Baptiste Schwilgué, who remodeled the clock around 1840.

The enigma of the natural order

In 2019 a book I wrote was published and distributed with the Spanish newspaper El País in a collection dedicated to the popularization of mathematics. The translation into English of my book title is Everything is Number: Is Reality Mathematical?

I addressed the problem of whether mathematical ideas correspond to an external reality, or if on the contrary they are arbitrary and vary with our current mentality. In other words, the question is whether mathematics is discovered, or invented. In one of the posts in this blog I dealt with this issue in relation to the real existence (or not) of the digits of number π (pi).

In the last chapter of that book I addressed a related issue: whether scientific theories, especially those proposed by physicists, are true (in the sense that they represent an underlying reality independent of us), or if are they mental or social constructs unrelated to a reality that could be unknowable (such as Kant's noumena) or even non-existent. I suppose my readers won't be surprised if I say that my personal position is clearly realistic, as is that of many physicists, while supporters of the anti-realist hypothesis tend to be predominantly philosophers.