Article View: sci.physics.relativity
Article #6929EINSTEINIANS REINTRODUCE ABSOLUTE SIMULTANEITY
From: Pentcho Valev
Date: Sat, 21 Mar 2009 07:04
Date: Sat, 21 Mar 2009 07:04
154 lines
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10953 bytes
Clever Einsteinians (mainly philosophers) clearly see the absurdity and even danger (for Einsteiniana of course) involved in Einstein's famous "relativity of simultaneity" and are desperately trying to get rid of the concept, in incredibly convoluted ways: http://philsci-archive.pitt.edu/archive/00002760/01/ReaTimePTS.pdf Brian Pitts: "Relativistic physics causes a difficulty for A-theorist in that the lack of absolute simultaneity in STR and GTR casts doubt on the objectivity of temporal becoming. I have demonstrated the possibility of deriving Einstein's equations using a modified Lagrangian density L from GTR, where the new L contained absolute simultaneity....The relativistic twin paradox is the context for one argument sketch. If one twin stays home while the other travels, the travelling twin will be younger upon his return than the homebody sibling. If the travelling twin merely takes an airplane around the world, this age difference will be negligible and well within the modest precision of common-sense judgments of presentness, as Huggett notes. But if the travelling twin takes a rocket into distant space and then returns, he might be years younger than his homebody sibling. Let us assume that each twin has his own local flow of time and that it is given by his relativistic proper time. Let the traveller leave at age 30, and return at age 35 to meet his 40-year-old twin sister. Though the twins' presents matched adequately before the traveller left, after his return their presents disagree by five years even when they embrace. It would be most peculiar if, upon the traveller's return, the two twins' consciousnesses are years apart when their bodies embrace; then each would encounter not his real twin, but an unconscious zombie (in basically the sense of David Chalmers (Chalmers, 1996)). Such a result is, I take it, a reductio ad absurdum. To be sure, the space travelling twin story is merely a thought experiment, unlike the airplane case. But this story (apart from the talk of presents) is the conventional wisdom about the twin paradox in relativity. If this conventional wisdom is accepted, then giving each person his own local flow, and having it correspond to relativistic proper time, leads to the absurdity of zombies.....Whether a theist or not, one also presumably needs to ground intersubjective simultaneity in the context of cosmic twin paradox scenarios, and a global present appears to be the one obvious solution. It therefore seems plausible, though not absolutely certain, that the experience of temporal passage, etc., that one should infer a global present, not merely local presents. It seems appropriate, then, to want absolute simultaneity to appear in the laws of physics." http://www.amazon.com/Relativity-Simultaneity-Routledge-Contemporary-Philosophy/dp/0415701740 Einstein, Relativity and Absolute Simultaneity (Routledge Studies in Contemporary Philosophy) "Einstein, Relativity and Absolute Simultaneity is an anthology of original essays by an international team of leading philosophers and physicists who, on the centenary of Albert Einsteins Special Theory of Relativity, come together in this volume to reassess the contemporary paradigm of the relativistic concept of time. A great deal has changed since 1905 when Einstein proposed his Special Theory of Relativity, and this book offers a fresh reassessment of Special Relativitys relativistic concept of time in terms of epistemology, metaphysics and physics. There is no other book like this available; hence philosophers and scientists across the world will welcome its publication." "Unfortunately for Einstein's Special Theory, however, its epistemological and ontological assumptions are now seen to be questionable, unjustified, false, perhaps even illogical." Craig Callender: "In my opinion, by far the best way for the tenser to respond to Putnam et al is to adopt the Lorentz 1915 interpretation of time dilation and Fitzgerald contraction. Lorentz attributed these effects (and hence the famous null results regarding an aether) to the Lorentz invariance of the dynamical laws governing matter and radiation, not to spacetime structure. On this view, Lorentz invariance is not a spacetime symmetry but a dynamical symmetry, and the special relativistic effects of dilation and contraction are not purely kinematical. The background spacetime is Newtonian or neo- Newtonian, not Minkowskian. Both Newtonian and neo-Newtonian spacetime include a global absolute simultaneity among their invariant structures (with Newtonian spacetime singling out one of neo-Newtonian spacetimes many preferred inertial frames as the rest frame). On this picture, there is no relativity of simultaneity and spacetime is uniquely decomposable into space and time." http://www.newscientist.com/article/mg20026831.500-what-makes-the-universe-tick.html "General relativity knits together space, time and gravity. Confounding all common sense, how time passes in Einstein's universe depends on what you are doing and where you are. Clocks run faster when the pull of gravity is weaker, so if you live up a skyscraper you age ever so slightly faster than you would if you lived on the ground floor, where Earth's gravitational tug is stronger. "General relativity completely changed our understanding of time," says Carlo Rovelli, a theoretical physicist at the University of the Mediterranean in Marseille, France.....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." http://www.pitt.edu/~jdnorton/Goodies/passage/index.html John Norton, 1 Mar 2009: "A common belief among philosophers of physics is that the passage of time of ordinary experience is merely an illusion. The idea is seductive since it explains away the awkward fact that our best physical theories of space and time have yet to capture this passage. I urge that we should resist the idea. We know what illusions are like and how to detect them. Passage exhibits no sign of being an illusion....Following from the work of Einstein, Minkowski and many more, physics has given a wonderfully powerful conception of space and time. Relativity theory, in its most perspicacious form, melds space and time together to form a four- dimensional spacetime. The study of motion in space and and all other processes that unfold in them merely reduce to the study of an odd sort of geometry that prevails in spacetime. In many ways, time turns out to be just like space. In this spacetime geometry, there are differences between space and time. But a difference that somehow captures the passage of time is not to be found. There is no passage of time. There are temporal orderings. We can identify earlier and later stages of temporal processes and everything in between. What we cannot find is a passing of those stages that recapitulates the presentation of the successive moments to our consciousness, all centered on the one preferred moment of "now." At first, that seems like an extraordinary lacuna. It is, it would seem, a failure of our best physical theories of time to capture one of time's most important properties. However the longer one works with the physics, the less worrisome it becomes....I was, I confess, a happy and contented believer that passage is an illusion. It did bother me a little that we seemed to have no idea of just how the news of the moments of time gets to be rationed to consciousness in such rigid doses.....Now consider the passage of time. Is there a comparable reason in the known physics of space and time to dismiss it as an illusion? I know of none. The only stimulus is a negative one. We don't find passage in our present theories and we would like to preserve the vanity that our physical theories of time have captured all the important facts of time. So we protect our vanity by the stratagem of dismissing passage as an illusion." Some day the world will realize in horror that the problem has always had a solution much simpler than the solutions clever Einsteinians (mainly philosophers) offer: http://blog.oup.com/2009/03/relativity/ The Oxford Companion to the History of Modern Science: "In the thought experiment Einstein often described, an observer on an embankment sees a light flash from the middle of a passing railroad carriage equipped with a mirror at either end. According to relativity, an observer seated at the center of the car would see the light returned from the mirrors simultaneously. But the observer on the embankment would see the flash from the forward mirror after that from the rear: the light has farther to go to meet and return from the forward than from the rear mirror, and the speed of light by hypothesis is the same in both directions. On a ballistic theory of light, the return flashes occur simultaneously for both parties: to the traveling observer, the light has the same speed in both directions; to the stationary one, the speed in the forward direction exceeds that in the opposite direction by twice the speed of the carriage." Pentcho Valev pvalev@yahoo.com
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X-Google-Thread: 10f545,d225936fbdf30230,start X-Google-Thread: 10b271,d225936fbdf30230,start X-Google-Thread: fa4c1,d225936fbdf30230,start X-Google-Attributes: gid10f545,gid10b271,gidfa4c1,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: arc1-ca.pugleaf.net!g2news1.google.com!postnews.google.com!h28g2000yqd.googlegroups.com!not-for-mail From: Pentcho Valev <pvalev@yahoo.com> Newsgroups: sci.physics.relativity,sci.physics,fr.sci.physique Subject: EINSTEINIANS REINTRODUCE ABSOLUTE SIMULTANEITY Date: Sat, 21 Mar 2009 00:04:48 -0700 (PDT) Organization: http://groups.google.com Lines: 154 Message-ID: <747dcd6d-9533-45cd-926d-3f701a23f228@h28g2000yqd.googlegroups.com> NNTP-Posting-Host: 79.100.231.46 Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Trace: posting.google.com 1237619089 11036 127.0.0.1 (21 Mar 2009 07:04:49 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Sat, 21 Mar 2009 07:04:49 +0000 (UTC) Complaints-To: groups-abuse@google.com Injection-Info: h28g2000yqd.googlegroups.com; posting-host=79.100.231.46; posting-account=Lz-LbgoAAABPDavKeW-eYeobwLHD_cvQ User-Agent: G2/1.0 X-HTTP-UserAgent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30),gzip(gfe),gzip(gfe)