A constant speed of light in all reference frames? Surely you can't be serious.
in [Relativity]
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From: Sue... on 9 Mar 2010 13:24 On Mar 9, 12:39 pm, PD <thedraperfam...(a)gmail.com> wrote: > On Mar 9, 11:14 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > On 9 Mar, 14:26, PD <thedraperfam...(a)gmail.com> wrote: > > > > On Mar 9, 7:49 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > On 8 Mar, 22:55, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > On Mar 6, 5:32 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > What confuses me is that, if the clocks run slow by 2% for all the > > > > > > time that they are moving, how does one reconcile this with the fact > > > > > > that, if one uses the frame of one of the moving clocks, say clock B, > > > > > > then it seems to be to be your argument that there is no slowdown at > > > > > > all for B, and it is the other clocks, A and C, that slow down (i.e. > > > > > > *disregarding* both acceleration and propagation delays). > > > > > > Be careful. The acceleration profiles are common between B and C, but > > > > > they are not common to A. So while there is no difference between B > > > > > and C due to the acceleration, you CANNOT say that the acceleration > > > > > has no effect whatsoever. In fact, it is the indisputable fact that B > > > > > and C accelerate and A does NOT accelerate that makes the situation > > > > > nonsymmetric for A. This is what makes the worldline for A straight, > > > > > and the worldline for B and C kinked. > > > > > Yes, but we're supposed to have isolated the effect of acceleration, > > > > and disregarded it. > > > > No, we did not. We said that it cannot account for the DIFFERENCE > > > between B and C, but this does not discount or remove acceleration > > > from further consideration, particularly with regard to how clock A's > > > rate is seen by B. > > > > > And in any event, the more important question is > > > > the discrepancy between B and C. > > > > > > Two places where I will try to intercept misconceptions. > > > > > 1. The first temptation is to say, well, if the kink is what's > > > > > responsible for the time dilation, then all the dilating must happen > > > > > during the acceleration. That is not the case. Note the time dilation > > > > > is different for B and C, even though they have the same kink (the > > > > > same acceleration profile). The fact that there IS a kink is what > > > > > makes the elapsed time less on B and C than it is on A (where there is > > > > > no kink), but how much less depends on the steepness and length of the > > > > > straight parts of the worldline on either side of the kink. > > > > > As I say, I've stipulated that we are measuring on the outbound > > > > journey, before any of the clocks have turned back. So we've had one > > > > episode of acceleration and now B and C are travelling at the same > > > > speed away from the origin point, but in opposite directions. What > > > > amount of time dilation does C suffer relative to B? Nil? 2%? 4%? > > > > It's not that simple, and to get a number, you need to use the math. > > > Sorry, but that's the facts. The 2% is the Lorentz dilation factor, > > > and that is given by a function 1/sqrt(1-v^2/c^2), and you can see > > > that doubling the speed will not double the Lorentz dilation factor. > > > Furthermore, the speed of C relative to B is not twice the velocity of > > > B with respect to A, because the relation for combining velocities is > > > (v1+v2)/(1+v1*v2/c^2). > > > > To find out what the Lorentz dilation factor is for C relative to B, > > > then you simply need to put in the numbers and crank. > > > So anyway, the point is that C will be time dilated relative to B (and > > the same for B relative to C). Yes? > > Yes. > > > > > Right, so if both are dilated relative to the other, then exactly how > > do they equalise with each other again when they return to their > > original location at A? > > Well, first of all, they don't, in the scenario you suggested, as I've > noted. > > > By definition, all dilation effects measured > > between B and C on the outbound trip, must be totally reversed on the > > inbound trip (although we accept both will be dilated relative to A). > > Yes? > > Yes. I'll take the symmetric case here, where they both travel outward > and back the same distance. > > The details here are interesting, and again, it depends a little on > what's actually being measured. This is also covered and explained > nicely in the link that I gave you, so I do recommend you read that. > You have to first keep in mind that the B and C clocks are not in the > same place, so it takes some care to explain what you mean when you > say that B sees that clock C is running slow. How exactly is the > information exchanged and the propagation time corrected for? See the > links. In a nutshell, and under one such scenario, what B sees is the > following: > 1. On the outward trip, C's clock is running slow, so that it is > behind B's clock by the time the outward journey ends. > 2. On the turnaround, C's clock leaps forward so that it is *ahead* of > B's clock by the time the turnaround is complete. > 3. On the inbound trip, C's clock is running slow, so that it ends up > showing the same time as B's clock by the time the inward journey > ends. > ================== > It's important for you to understand that the leap-ahead of C's clock > is not due to any physical process affecting clock C, because it is > the turnaround of *B* that is change that invokes it. Again, > understanding why this happens is in the details of how the > communication of the reading of the clock is performed (and > propagation accounted for). I'll not go into more detail here, as I've > already provided a link to a more thorough discussion. Indeed... one must allow for to loss to predatory organisms that might inhabit the communication path. << University of Hohenheim researchers are hoping to receive help from nature in their fight against ticks. Worms, fungi and wasps that feed on ticks will now be used to reduce the number of these dangerous disease carriers.>> http://www.bio-pro.de/magazin/wissenschaft/archiv_2007/index.html?lang=en&artikelid=/artikel/02099/index.html Sue... > > PD
From: Ste on 9 Mar 2010 14:25 On 9 Mar, 17:20, PD <thedraperfam...(a)gmail.com> wrote: > On Mar 9, 11:07 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > What I haven't found compelling is the argument that falsificationism > > is the hallmark of science as against non-science or religion. What is > > quite clear from the judgment is that it was that court's view that it > > is naturalism that is the hallmark of science. Indeed to quote the > > judge: "This rigorous attachment to natural explanations is an > > essential attribute to > > science by definition and by convention." > > Where "natural" is distinguished from "supernatural", this being said > at least ... oh, never mind, I lost count. > > You've had numerous people from the scientific field flatly averring > that falsification and experimental test IS the hallmark of science, > and yet you find it less than compelling. This perhaps goes back to > the issue that you believe what you want to believe, and you choose > your experts according to whether they hold the same belief. And this > IS a hallmark of religious thinking. But this case was *your* quoted authority Paul. I didn't choose it, you did! I agree that some sort of testability plays a part in science, but as I say I remain unconvinced that testability (as a practical rather than a notional proposition) defines science. In that judgment, the judge seems satisfied with the basic proposition that science is naturalistic, and ID is not naturalistic, and hence not science. There is no extensive discussion of testability. Insofar as testability is mentioned as a requirement of science at all, it is only in juxtaposing it against the obvious untestability of supernatural explanations. Again, I quote (from the Claimant's closing submissions): "You heard plaintiffs' experts Pennock, Padian, and Miller testify that that scientific propositions have to be testable. [...] Of course, there is an obvious reason that Intelligent Design hasn't been tested - it can't be. The proposition that a supernatural intelligent designer created a biological system is not testable, and can never be ruled out." "[Intelligent Design] has been unanimously rejected by the National Academy of Science, the American Association for Advancement of Science, and every other major scientific and science education organization that has considered the issue, including, we learned this morning, the American Society of Soil Scientists. The fact that it invokes the supernatural is, by itself, disqualifying."
From: Ste on 9 Mar 2010 14:56 On 9 Mar, 17:39, PD <thedraperfam...(a)gmail.com> wrote: > On Mar 9, 11:14 am, Ste <ste_ro...(a)hotmail.com> wrote: > > Yes. I'll take the symmetric case here, where they both travel outward > and back the same distance. Yes, we are back to talking about the symmetric case, although on reflection I might not have made that clear. > The details here are interesting, and again, it depends a little on > what's actually being measured. This is also covered and explained > nicely in the link that I gave you, so I do recommend you read that. > You have to first keep in mind that the B and C clocks are not in the > same place, so it takes some care to explain what you mean when you > say that B sees that clock C is running slow. How exactly is the > information exchanged and the propagation time corrected for? See the > links. In a nutshell, and under one such scenario, what B sees is the > following: > 1. On the outward trip, C's clock is running slow, so that it is > behind B's clock by the time the outward journey ends. > 2. On the turnaround, C's clock leaps forward so that it is *ahead* of > B's clock by the time the turnaround is complete. > 3. On the inbound trip, C's clock is running slow, so that it ends up > showing the same time as B's clock by the time the inward journey > ends. When we talk of the "turnaround", can we be a bit more specific about what is happening? Also, bear in mind that *both* turnaround at the same time. I also find it implausible that C could leap ahead of B. The more plausible explanation, surely, is that B slows down dramatically relative to C. So for example, if both clocks stopped moving (relative to A) while at their farthest distance from each other, then for a short time the other clock would appear to leap ahead (actually a slowing of the reference clock), until the effects of each clock stopping had actually propagated to the other clock, at which point they would snap back into synchronisation again (propagation delays disregarded). Yes?
From: PD on 9 Mar 2010 15:03 On Mar 9, 1:25 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 9 Mar, 17:20, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Mar 9, 11:07 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > What I haven't found compelling is the argument that falsificationism > > > is the hallmark of science as against non-science or religion. What is > > > quite clear from the judgment is that it was that court's view that it > > > is naturalism that is the hallmark of science. Indeed to quote the > > > judge: "This rigorous attachment to natural explanations is an > > > essential attribute to > > > science by definition and by convention." > > > Where "natural" is distinguished from "supernatural", this being said > > at least ... oh, never mind, I lost count. > > > You've had numerous people from the scientific field flatly averring > > that falsification and experimental test IS the hallmark of science, > > and yet you find it less than compelling. This perhaps goes back to > > the issue that you believe what you want to believe, and you choose > > your experts according to whether they hold the same belief. And this > > IS a hallmark of religious thinking. > > But this case was *your* quoted authority Paul. I didn't choose it, > you did! I made no statement about it being an authoritative declaration. What I said is that the definition is acknowledged (and it is) in a statement intended for layfolk outside the scientific field, which I took this ruling to be. Your return comment was that this is in fact not a statement intended for layfolk at all, and there are nuances in how to read a legal judgment, wherein it is not sufficient to actually read the statement in the section about how intelligent design and creationism are distinguished from science, but instead one must count instances of words. Moreover, one should -- in the context of a legal opinion -- ignore the explicit identification of "methodological naturalism" with the scientific method and the explicit contrast of naturalism against creationism's supernaturalism, and feel free to interpret naturalism however the hell one wants, including one's favorite philosophical connotation, though that connotation is unmentioned entirely in the judgment. In these instructions on how to properly read legal judgments, I of course defer to you, and I thank you for the patient instruction. > > I agree that some sort of testability plays a part in science, but as > I say I remain unconvinced that testability (as a practical rather > than a notional proposition) defines science. I may be of the opinion that architecture is art, and that structural integrity is not an essential distinction between the two. I might even find some source that agrees with this. However, if I find that a number of architects strenuously disagree with me, then I suppose I would reconsider the fitness of my position. > In that judgment, the > judge seems satisfied with the basic proposition that science is > naturalistic, and ID is not naturalistic, and hence not science. There > is no extensive discussion of testability. Insofar as testability is > mentioned as a requirement of science at all, it is only in > juxtaposing it against the obvious untestability of supernatural > explanations. > > Again, I quote (from the Claimant's closing submissions): "You heard > plaintiffs' experts Pennock, Padian, and Miller testify that that > scientific propositions have to be testable. [...] Of course, there is > an obvious reason that Intelligent Design hasn't been tested - it > can't be. The proposition that a supernatural intelligent designer > created a biological system is not testable, and can never be ruled > out." > > "[Intelligent Design] has been unanimously rejected by the National > Academy of Science, the American Association for Advancement of > Science, and every other major scientific and science education > organization that has considered the issue, including, we learned this > morning, the American Society of Soil Scientists. The fact that it > invokes the supernatural is, by itself, disqualifying."
From: PD on 9 Mar 2010 15:10
On Mar 9, 1:25 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 9 Mar, 17:20, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Mar 9, 11:07 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > What I haven't found compelling is the argument that falsificationism > > > is the hallmark of science as against non-science or religion. What is > > > quite clear from the judgment is that it was that court's view that it > > > is naturalism that is the hallmark of science. Indeed to quote the > > > judge: "This rigorous attachment to natural explanations is an > > > essential attribute to > > > science by definition and by convention." > > > Where "natural" is distinguished from "supernatural", this being said > > at least ... oh, never mind, I lost count. > > > You've had numerous people from the scientific field flatly averring > > that falsification and experimental test IS the hallmark of science, > > and yet you find it less than compelling. This perhaps goes back to > > the issue that you believe what you want to believe, and you choose > > your experts according to whether they hold the same belief. And this > > IS a hallmark of religious thinking. > > But this case was *your* quoted authority Paul. I didn't choose it, > you did! > > I agree that some sort of testability plays a part in science, but as > I say I remain unconvinced that testability (as a practical rather > than a notional proposition) defines science. In that judgment, the > judge seems satisfied with the basic proposition that science is > naturalistic, and ID is not naturalistic, and hence not science. There > is no extensive discussion of testability. Insofar as testability is > mentioned as a requirement of science at all, it is only in > juxtaposing it against the obvious untestability of supernatural > explanations. > > Again, I quote (from the Claimant's closing submissions): "You heard > plaintiffs' experts Pennock, Padian, and Miller testify that that > scientific propositions have to be testable. [...] Of course, there is > an obvious reason that Intelligent Design hasn't been tested - it > can't be. The proposition that a supernatural intelligent designer > created a biological system is not testable, and can never be ruled > out." > > "[Intelligent Design] has been unanimously rejected by the National > Academy of Science, the American Association for Advancement of > Science, and every other major scientific and science education > organization that has considered the issue, including, we learned this > morning, the American Society of Soil Scientists. The fact that it > invokes the supernatural is, by itself, disqualifying." As a passing metacomment about this discussion, I will only remark that at a juncture were I had the opportunity to choose between physics and philosophy as a career path, one of the reasons I did not choose philosophy is that it seemed to be more about the dance than about the truth. The implicit assumption seemed to be that the better the dance, the more likely it would represent truth, and there was no recourse to any more objective adjudicator (such as physics uses when it checks how nature actually behaves) than the dancers themselves. This, philosophy shares with the practice of law, which perhaps accounts for their appeal to you. Many times during our conversations here, I have gotten the impression that you are more interested in the verbal dance than in what nature actually does and what we think we know about that and why. PD |