Every blog can’t be about politics or teaching. This post is written for science geeks like me and people who like warm baths. Other readers should beware.
In one of my favorite episodes of The Big Bang Theory, Leonard Hofstadter (John Galecki) and Leslie Winkle (Sara Gilbert) are necking on the couch when Sheldon Cooper interrupts and the three end up fighting over whether String Theory or Loop Quantum Gravity better explains the universe. Leonard and Sheldon defend String Theory and Leslie, infuriated, walks out, swearing that she and Leonard are irreparably incompatible and that their relationship is permanently over. Leslie exclaims, “Tell me Leonard, how will we raise the children?”
String Theory and Loop Quantum Gravity are theoretical attempts to meld the two foundational principles of twentieth century physic, quantum mechanics and the General Theory of Relativity, into a “theory of everything.” The problem for physicists is that while General Relativity as proposed by Albert Einstein successfully describes big things like the formation and movement of stars, planets, galaxies, and Black Holes, and Quantum Mechanics explains the sub-atomic world, they offer inconsistent explanations that cannot both be right. As portrayed in The Big Band Theory, advocates for both theories tend to defend their positions with religious zeal.
String theorists argue that subatomic particles are made up of incredibly tiny, functionally invisible, loops of vibrating string. If scientists are willing to accept the existence of the vibrating strings, General Relativity and Quantum Mechanics can be integrated into one overall explanation of the gigantic and the miniscule.
In 2011, at an American Museum of Natural History sponsored conference in New York City, Neil deGrasse Tyson, director of the museum’s Hayden Planetarium, pointed out that despite concerted efforts, little progress had been made in establishing String Theory and he asked whether its advocates were “chasing a ghost.” In order to make their math “elegant,” String theorists predict the existence of an infinite number of parallel universes and at least ten unopened dimensions that scientists will never be able to examine. Sabine Hossenfelder, a physicist at the Frankfurt Institute for Advanced Studies in Germany, dismisses String theorists because most of their predictions are untestable and for postulating an “endless amount of mathematical constructions that have no known relationship to observation."
Hossenfelder, not surprisingly, like the fictional Leslie Winkler, tends to favor Loop Quantum Gravity or LQG. She thinks part of the conflict is that String theorists and LQG approach solutions to the nature of the universe from different directions and sometimes are looking at different things. According to Hossenfelder, String Theory is primarily concerned with the “behavior of objects,” really tiny ones that can’t be observed, while LQG is bent on explaining forces shaping the universe and what Einstein called “space-time.”
Brian Greene, a leading proponent of String Theory, continues to argue that it is only a matter of time until its validity is established and he compares the theoretical work of String theorists to the theoretical work of Albert Einstein, they both proposed theories of the universe before it was possible to conduct scientific experiments.
I think Greene incorrectly explains Einstein’s approach to solving physics problems. Greene starts with mathematical equations and then comes up with a theoretical explanation, String Theory, that he argues is consistent with the math. But that is not how Einstein worked. Einstein conducted thought experiments in his head, proposed actually experiments that would verify his thought experiments, and then used mathematics to describe his ideas with precision. For String Theory, it is math first, real world second. For Einstein, it was the other way around, real world first and math second.
Einstein actually challenged the math first approach in a 1921 address to the Prussian Academy of Sciences in Berlin, Germany that he called “Geometry and Experience.” According to Einstein, “One reason why mathematics enjoys special esteem, above all other sciences, is that its laws are absolutely certain and indisputable, while those of all other sciences are to some extent debatable and in constant danger of being overthrown by newly discovered facts.” Einstein rhetorically asked, “How can it be that mathematics, being after all a product of human thought which is independent of experience, is so admirably appropriate to the objects of reality? Is human reason, then, without experience, merely by taking thought, able to fathom the properties of real things?” Einstein then answered his own question, “As far as the laws of mathematics refer to reality, they are not certain; and as far as they are certain, they do not refer to reality.” Bottom line, the mathematical certainty sought by the String theorist, at least according to Einstein, does not describe reality.
I admit I am not a mathematician. But in this case, that may not be a bad thing. When I read scientific journals or numbers laden economics articles, I tend to skip the math, leaving it to experts to check the numbers.
Recently Nobel Prize winning theoretical physicist Toshihide Maskawa died, he was 81 and a survivor of an American bombing attack during World War II. Maskawa was awarded the Nobel Prize for his work on asymmetrical aspects of sub-atomic particles and the realization that there were six types of sub-atomic particles known as quarks. Apparently Maskawa did some of his best thinking while taking a warm bath.
The mathematical model Maskawa used in his research suggested that there were four quarks, “up,” “down,” “strange,” and “charmed,” but that model didn’t explain asymmetry. Asymmetry, why more people are right-handed than left-handed, is important in physics because if there were equal amounts of matter and anti-matter created by the Big Bang (the formation of the universe, not the television show), the universe would have quickly collapsed back on itself and stars and planets and people would never have emerged.
Calmed by the warm bath, Maskawa postulated that if there were six quarks, the asymmetry that allowed for the formation of the universe could be explained. Based on his insight, experimental physicists working with particle accelerators discovered two more quarks, “top” and “bottom,” once again establishing the priority of experimentation before the mathematical description and the importance of taking warm baths.
Does any of this have significant meaning for the world we live in? I have no idea, but I enjoy the intellectual debate. I also agree with Einstein’s approach, the math should conform to the reality of the world, not pretend it works the other way around.
At this point I have three confessions to make. First, I love taking a warm bath every evening where I do some of my best thinking. Second, I have no idea what Einstein would say about the Loopy versus Stringy debate, but he would probably stick out his tongue. Third, Neil deGrasse Tyson and I both went to the Bronx High School of Science. Brian Greene attended our arch-rival Stuyvesant. This battle over the legitimacy of String Theory is like Yankees-Red Sox, Celtics-Lakers, or Alabama versus Georgia in football.
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