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Pentcho Valev

Posts: 6,212
Registered: 12/13/04
Posted: Oct 31, 2013 9:15 AM
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The current rallying cry in Einsteiniana:

"Brothers Einsteinians, let's somehow get rid of the consequent, Einstein's idiotic concept of time, and preserve the antecedent, Einstein's 1905 false constant-speed-of-light postulate!"
"Many physicists argue that time is an illusion. Lee Smolin begs to differ. (...) Smolin wishes to hold on to the reality of time. But to do so, he must overcome a major hurdle: General and special relativity seem to imply the opposite. In the classical Newtonian view, physics operated according to the ticking of an invisible universal clock. But Einstein threw out that master clock when, in his theory of special relativity, he argued that no two events are truly simultaneous unless they are causally related. If simultaneity - the notion of "now" - is relative, the universal clock must be a fiction, and time itself a proxy for the movement and change of objects in the universe. Time is literally written out of the equation. Although he has spent much of his career exploring the facets of a "timeless" universe, Smolin has become convinced that this is "deeply wrong," he says. He now believes that time is more than just a useful approximation, that it is as real as our guts tell us it is - more real, in fact, than space itself. The notion of a "real and global time" is the starting hypothesis for Smolin's new work, which he will undertake this year with two graduate students supported by a $47,500 grant from FQXi."
"Newton and Leibniz debated this very point. Newton portrayed space and time as existing independently while Rovelli and Brown share Leibniz's view that time and space exist only as properties of things and the relationships between them. It is still not clear who is right, says John Norton, a philosopher based at the University of Pittsburgh, Pennsylvania. Norton is hesitant to express it, but his instinct - and the consensus in physics - seems to be that space and time exist on their own. The trouble with this idea, though, is that it doesn't sit well with relativity, which describes space-time as a malleable fabric whose geometry can be changed by the gravity of stars, planets and matter."
"Was Einstein wrong? At least in his understanding of time, Smolin argues, the great theorist of relativity was dead wrong. What is worse, by firmly enshrining his error in scientific orthodoxy, Einstein trapped his successors in insoluble dilemmas..."
"But our everyday intuitive sense - the Newtonian realist position - still has backers, scientific and philosophical. Enter the philosopher-physicist team of Roberto Unger and Lee Smolin. (...) Along with Lee Smolin, Unger is concentrating on a book with the draft title, The Singular Universe and the Reality of Time. They hope to lob it into the debate sometime next year..."
"Vous dites le temps c'est comme le paysage qui ne bouge pas..."
ETIENNE KLEIN: "Ça c'est une conception c'est pas forcement la bonne mais c'est celle que défend Einstein."
"C'est pas la vôtre?"
ETIENNE KLEIN: "Heu... disons que c'est une conception qui pose des problèmes quand on compare ce que dit la relativité d'Einstein à ce que dit une autre théorie physique qui s'appelle la physique quantique..."
New Scientist: "ADVANCES in physics often result from observations that don't fit theory: the Michelson-Morley experiment, for example, saw no universal ether, paving the way for Einstein's relativity. That successful theory is itself hard to square with one of the most universal observations of all. Relativity, and many subsequent physical theories, kill off the notion that time flows - but every human alive will argue otherwise. Well, almost every human: some physicists are resigned to the "block universe", with its static time. Others, however, feel that any theory that doesn't accommodate our experience must be flawed..."
New Scientist: "Saving time: Physics killed it. Do we need it back?"
The new great time war. Download audio: 04:40 : Roberto Unger: "Relativity of time in the local sense is an indisputed fact resulting from discoveries associated with Einstein's name. But the so-called Minkowski spacetime and in particular the dominant project in post-Einsteinian science of spacializing time, of treating time as if it were properly described by the metaphor "the fourth dimension" - all of that is metaphysics and not empirical discovery."
QUESTION: Setting aside any other debates about relativity theory for the moment, why would the speed of light be absolute? No other speeds are absolute, that is, all other speeds do indeed change in relation to the speed of the observer, so it's always seemed a rather strange notion to me.
LEE SMOLIN: Special relativity works extremely well and the postulate of the invariance or universality of the speed of light is extremely well-tested. It might be wrong in the end but it is an extremely good approximation to reality.
QUESTION: So let me pick a bit more on Einstein and ask you this: You write (p. 56) that Einstein showed that simultaneity is relative. But the conclusion of the relativity of simultaneity flows necessarily from Einstein's postulates (that the speed of light is absolute and that the laws of nature are relative). So he didn't really show that simultaneity was relative - he assumed it. What do I have wrong here?
LEE SMOLIN: The relativity of simultaneity is a consequence of the two postulates that Einstein proposed and so it is deduced from the postulates. The postulates and their consequences are then checked experimentally and, so far, they hold remarkably well.

Pentcho Valev

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