Cosmologic philosophy; two new books (Introduction)

by David Turell , Tuesday, September 20, 2016, 18:58 (2768 days ago) @ David Turell

A book by Roger Penrose thinks string theory is a dead end: - http://www.wsj.com/articles/cosmic-certainties-1474328303 - " String theory is by far the most popular attempt to do so. It posits that the basic constituents of the world are tiny vibrating strings. Depending on how a string vibrates, it appears as one kind of particle or another—an electron, a quark (of which protons and neutrons are made), a photon and so forth. For the math to work, it rather awkwardly turns out, the strings—and thus the world itself—must vibrate in a slew of extra dimensions. (The exact number of total dimensions—10 in some cases, 26 in others—differs in different models.) These dimensions are hidden, - *** - "Mr. Penrose finds these extra dimensions to be deeply unappealing. He argues that string theory can't be right. Part of the difficulty with figuring out if string theory or its rivals are true, he says, is that “often the crucial experiments are not available,” because they would require prohibitive amounts of energy. On the other hand most of the data we do have “simply confirms what is already known.” - *** - "Orthodox cosmologists believe that, in the very first instants after the big bang, the universe underwent an extremely rapid period of expansion, known as “inflation.” Inflation is required to explain the fact that the “cosmic microwave background ,” a signal that pervades the universe and that has been mapped to extraordinary precision by several NASA space probes, varies only minimally across the night sky. The CMB reflects the temperature of the early universe. Without inflation, physicists believe, distant parts of the sky are too far away from one another for the temperature between them to have reached an equilibrium. Mr. Penrose argues that this uniformity can instead be explained if the big bang wasn't the beginning of things but merely an expansion following an earlier collapse. He's not the first to propose a cyclical model, but he differs in proposing that, between cycles, mass itself would die away, a conjecture that solves certain mathematical problems he highlights. - *** - "In part because of the persuasiveness of Mr. Smolin's arguments, Mr. Penrose speculates that physics may have already reached peak string theory: “Its stranglehold on developments in fundamental physics has been stultifying,” he says. His insistence on finding clever experimental tests for novel theories is the only way physics will break free from its deadlock." - ************************************************************ - Here is Brian Cox book touting inflation and the multiverse: - https://www.theguardian.com/science/2016/sep/18/brian-cox-interview-it-is-a-book-about-... - Interviewer: "I remember talking to the cosmologist Paul Davies once, who seemed to tend to the view that the universe is somehow geared to understanding itself; all his observation led him to that conclusion. Can you sympathise with that idea?
I don't have that belief. It's the final anthropic principle: that there is something about the consistency of the universe that makes it necessary to be understood. I don't think that. In the book we talk about this idea of the inflationary multiverse. It's still a guess, but most cosmologists are tending toward that theory, I'd say.
How far are the dots apart for you to make that leap of understanding? - "The theory of inflation itself is almost nailed down. We teach it at undergraduate level, and the data supports it as far as we can tell. The idea of multiverses is not too big a leap from that. If that is right then you have essentially an infinity of universes and it follows there is a very natural, almost unavoidable mechanism for varying the laws of nature in each universe. Therefore the idea that we look out on a universe that has been waiting for us to appear in it and understand it is at best incidental. Because every possible sort of universe is made real by inflationary cosmology." - Comment: We are still stuck. No explanation of the Big Bang, inflationary theory still an unproven theory, string theory of no help, and multiverses a pipedream based on unproven theory. Whew!