From: Gerald O'Connell <goc.nul> Date: Tue, 27 Sep 2011 18:53:58 +0100 Archived: Wed, 28 Sep 2011 08:38:26 -0400 Subject: Re: D'oh! Light Speed Threshold Broken? >From: Martin Shough <parcellular.nul> >To: <post.nul> >Date: Mon, 26 Sep 2011 13:00:51 +0100 >Subject: Re: D'oh! Light Speed Threshold Broken? <snip> >So, if tachyonic neutrinos are not a new concept, why the fuss? >The real issue is not about exceeding the speed of light as >such, nor is it even about the possibility of detecting them. It >is about the possibility of causality violations that could >theoretically arise if the particles can be used to send >information, as in the much-discussed "tachyonic antitelephone" >thought experiment whereby a signal is sent back in time. Even >if superluminal neutrinos are detectable in the CERN conditions >it may yet be the case that there is a sort of cosmic censorship >going on, which somehow prevents information being transferred >and so preserves causality on the light cone, as happens all the >time (so far as anyone yet knows) with "instantaneous" nonlocal >entanglement in quantum theory. >If you think about it the situation is analogous: the very tiny >superluminal margin is not found from simply timing individual >particles but is calculated by a very complicated statistical >analysis done after the fact on distributed bursts of many >detections, and most importantly the reference frame of >measurement includes both emitter and detector with everything >callibrated and locked together by GPS and atomic clocks. This >reference frame is a local frame, i.e. it is made of light-speed >signals. To determine the neutrino time of flight crudely >speaking requires requires information to be sent separately at >light speed from A to B where a comparison is made afterwards. >In a terrestrial lab-scale setting this may seem over-subtle. >But imagine if the emitter is on a distant star 10 light years >away: How does one callibrate the reference frame of measurement >to prove that a neutrino has arrived a millionth of a second >earlier than it "ought" to have done? You cannot just "look and >see". You have to do it by sending radio or other local signals >at the speed of light, and 10 years later you can cal;culate the >result. This seems closely analogous to the quanglement >'problem' whereby remote events are instantaneously correlated, >but in a subtle way so that the correlation cannot be used for >signalling. >I'm not sure if this is a valid line of argument, but I suspect >it might be. Any thoughts? Yes, but I don't know how useful (or coherent) they are, so I'll just try them out on you :-) So let's assume that there are conditions under which neutrinos can exceed the speed of light. How much damage ensues to the current theoretical edifice? Not much, I would argue. Lots of key equations still stand up (in the sense that their explanatory force is undiminished) and some others might have to be tweaked. But that feels very much like 'business as usual' for the frontier of physics, where 'elegant' explanations are periodically undermined by new empirical data. I'm thinking here, for example, of recent speculation to the effect that the laws of physics may not be the same in all inertial frames of reference. More often than not this sort of undermining leads to small 'adjustments' rather than wholesale theoretical revision (or 'advance' as some might prefer to say). In this context I would incline to the view that your argument stands up. That is to say, short of a wholesale theoretical revision ( a 'new physics', I think you call it?), it looks as though you are right, though you may only be right for the time being. By that I mean that superluminal neutrinos are not necessarily sufficient cause for a wholesale theoretical revision. In saying this I'm not commenting on the adequacy of current theory so much as the reluctance of theoreticians to depart from it given the investment of human intellectual capital that has been made in it. However, the next wholesale theoretical revision may still be such as to preserve the validity of your argument. To illustrate my point, I'd invite you to conduct a brief thought experiment in the future history of science (OK, I know this is speculation about speculation, but bear with me): suppose that the edifice has to be rebuilt with the abandonment of one key assumption, and suppose that assumption were to be the (very) deeply embedded one that the mass/energy equivalence exhausts all existential categories? In other words, neutrinos can exceed the speed of light in a vacuum because they are neither mass nor energy, but a third type of thing. The fact that they appear to have a tiny mass may turn out to be a by-product of some over- arching truth about the nature of things that we just aren't onto yet. Alternatively, the wholesale theoretical revision that may invalidate your argument and cause lots of other trouble besides, is the one where causality is called into question. This is difficult to envisage and even harder to talk about! Nonetheless, this may become necessary. Right now, I'm not sure that many people have grasped the implications of this. Science and mathematics are underpinned by certain logical processes of an 'if - then'' nature. Broadly we can divide these into deductive and inductive processes. If causality is called into question (it doesn't have to be 'overturned' or abandoned' - there a still situations where it holds good, but we would have to accept that there are other situations where it doesn't hold good and a completely different explanatory apparatus is required), then so are the inductive processes that we take to be axiomatic (the deductive ones still stand because they are, ultimately, in the form of 'restatements' - the conclusions are already embedded somehow in the assumptions). This isn't just an inconvenience (see Dr Lucie Green's comment in the link Ray kindly supplied) to theoretical physicists, but big, big trouble for our entire way of thinking. As an aside, I'm increasingly annoyed about the way all this is being discussed: the 'Einstein proved Newton wrong and now Einstein has been proved wrong' characterisation is such rubbish. Einstein showed that Newton hadn't told the whole story, and now it looks as though Einstein might not have not the whole story. I don't think either of them would have had a problem with that. If they were both 'wrong', then I'd like to be wrong about a few things too! -- Gerald O'Connell http://www.saatchionline.com/gacoc Listen to 'Strange Days... Indeed' - The PodCast At: http://www.virtuallystrange.net/ufo/sdi/program/ These contents above are copyright of the author and UFO UpDates - Toronto. They may not be reproduced without the express permission of both parties and are intended for educational use only.
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