Known physics defeated by simple puzzle?
in [Relativity]
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From: Peter Webb on 10 Apr 2010 03:43 "Ste" <ste_rose0(a)hotmail.com> wrote in message news:a5efd3b8-2a31-4935-828b-234bb8569461(a)w17g2000yqj.googlegroups.com... > On 10 Apr, 07:44, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> > wrote: >> "Ste" <ste_ro...(a)hotmail.com> wrote in message >> >> news:da85279f-24ef-481b-93d0-287ce74db45d(a)y14g2000yqm.googlegroups.com... >> >> > On 10 Apr, 04:49, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> >> > wrote: >> >> I have some sympathy for your problem. I have no sympathy for the fact >> >> that >> >> instead of trying to understand how the Universe actually works, your >> >> position is that SR is wrong and/or Inertial, PD and I am wrong >> >> because >> >> we >> >> agree with SR and SR is wrong. >> >> > I do wish you'd stop framing the issue as "you're either with us or >> > against us". There is obviously some validity to SR - and I've said it >> > a million times. For us to argue about what explanation underlies SR, >> > or how to interpret it, is not to say SR is "wrong". >> >> But you do say SR is wrong, all the time, because you argue with its >> predictions. >> >> Lets see, for the record, whether you believe SR is wrong. >> >> Here are two specific predictions of SR. Tell me if you think they are >> correct: >> >> 1. Two twins - one travels to a start 1 light year away at 0.9c, turns >> around and returns at 0.9c. The travelling twin ages less than the stay >> at >> home because of relativistic time dilation. True of False? > > True, because there is a "real" slowdown of the astronaut twin. > > > >> 2. 40 foot ladder moves into 20 foot barn at 0.9c. When the midpoint of >> the >> ladder is at the midpoint of the barn, the doors at each end are closed >> simultaneously (in the barn's frame of reference), a photo is taken, and >> the >> doors are quickly re-opened. The photo will show the ladder entirely >> within >> the barn. True or False? > > It is unclear how to interpret this prediction. It concerns the contents of a photograph. Where is the confusion?
From: Inertial on 10 Apr 2010 03:59 "Ste" <ste_rose0(a)hotmail.com> wrote in message news:8431a5cd-222a-4118-9d15-7bcdf6450410(a)c36g2000yqm.googlegroups.com... > On 10 Apr, 07:38, "Inertial" <relativ...(a)rest.com> wrote: >> "Ste" <ste_ro...(a)hotmail.com> wrote in message >> >> > The point is simply to talk in qualitative >> > terms about what happens to "simultaneity" between the points at the >> > start and at the end at which we agree that the clocks are >> > synchronised. >> >> It changes > > Will you quantify this change? I thought you just wanted to talk in qualitative terms. You also say you don't want to see math, so I'm not sure what you are expecting here >> > So, whether it "appears" slow or is "really" slow, the question is >> > does it slow down or speed up (whether really or apparently) >> >> Two different questions .. two different answers > > I didn't notice two questions, and I was the one who wrote it. Whether is 'really' slows down and whether it 'appearently' slows down. Though I'm not sure what you mean, I'm pretty sure I've answered both questions already >> > depending >> > on whether it is approaching or receding? In other words, if we moved >> > the clocks in the opposite direction (starting near, and then receding >> > to a point in the distance)? >> >> The clocks always tick at the correct rate .. they are neither fast nor >> slow >> in their own frames. > > Yes, that went without saying. It's like saying a "clock is never slow > relative to its own rate". No .. it isn't. >> A frame moving relative to a clock will measure the clock as ticking >> slower. >> Less elapsed time will show between an pair of events for the relatively >> moving clock than an at-rest clock. That is independent of the direction >> of >> the relative motion. >> >> I had though we agreed to ignore illusions due to propagation delays. > > Indeed, but when you started talking of the clocks "speeding up", that > caused me confusion. Why? Just do not worry about optical illusions and concentrate on what is actually going on. >> The illusion due to propagation delays is that a clock moving away from >> you >> will look like it is running a bit slower, because it takes longer and >> longer time for the light to reach you. >> >> The illusion due to propagation delays is that a clock moving toward you >> will look like it is running a bit faster, because it takes short and >> shorter time for the light to reach you. > > Indeed. But, I take it from your other statements above, correcting > for these ilusions Which is what I was originally tlaking about > would leave a small remainder of slowing, There would be the slowing SR predits. You are talking about additonal optical illusions. > based on > the relative speed between the clocks? (and not based on the direction > of relative movement?) Yes. I've already said that.
From: Inertial on 10 Apr 2010 04:01 "Ste" <ste_rose0(a)hotmail.com> wrote in message news:a5efd3b8-2a31-4935-828b-234bb8569461(a)w17g2000yqj.googlegroups.com... > On 10 Apr, 07:44, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> > wrote: >> "Ste" <ste_ro...(a)hotmail.com> wrote in message >> >> news:da85279f-24ef-481b-93d0-287ce74db45d(a)y14g2000yqm.googlegroups.com... >> >> > On 10 Apr, 04:49, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> >> > wrote: >> >> I have some sympathy for your problem. I have no sympathy for the fact >> >> that >> >> instead of trying to understand how the Universe actually works, your >> >> position is that SR is wrong and/or Inertial, PD and I am wrong >> >> because >> >> we >> >> agree with SR and SR is wrong. >> >> > I do wish you'd stop framing the issue as "you're either with us or >> > against us". There is obviously some validity to SR - and I've said it >> > a million times. For us to argue about what explanation underlies SR, >> > or how to interpret it, is not to say SR is "wrong". >> >> But you do say SR is wrong, all the time, because you argue with its >> predictions. >> >> Lets see, for the record, whether you believe SR is wrong. >> >> Here are two specific predictions of SR. Tell me if you think they are >> correct: >> >> 1. Two twins - one travels to a start 1 light year away at 0.9c, turns >> around and returns at 0.9c. The travelling twin ages less than the stay >> at >> home because of relativistic time dilation. True of False? > > True, because there is a "real" slowdown of the astronaut twin. If by 'slow down' you mean 'aged less' as per the question asked. Why do you have to continually introduce other terms like '"real" slowdown'? >> 2. 40 foot ladder moves into 20 foot barn at 0.9c. When the midpoint of >> the >> ladder is at the midpoint of the barn, the doors at each end are closed >> simultaneously (in the barn's frame of reference), a photo is taken, and >> the >> doors are quickly re-opened. The photo will show the ladder entirely >> within >> the barn. True or False? > > It is unclear how to interpret this prediction. No .. its VERY clear. READ !!!
From: Ste on 10 Apr 2010 06:07 On 10 Apr, 08:59, "Inertial" <relativ...(a)rest.com> wrote: > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > news:8431a5cd-222a-4118-9d15-7bcdf6450410(a)c36g2000yqm.googlegroups.com... > > > On 10 Apr, 07:38, "Inertial" <relativ...(a)rest.com> wrote: > >> "Ste" <ste_ro...(a)hotmail.com> wrote in message > > >> > The point is simply to talk in qualitative > >> > terms about what happens to "simultaneity" between the points at the > >> > start and at the end at which we agree that the clocks are > >> > synchronised. > > >> It changes > > > Will you quantify this change? > > I thought you just wanted to talk in qualitative terms. I did, but not at such a ridiculously broad level. > You also say you > don't want to see math, so I'm not sure what you are expecting here Just for you to say, for example, "when the local clock accelerates, the distant clock falls out of simultaneity and leaps ahead... etc." or something of that kind. > >> A frame moving relative to a clock will measure the clock as ticking > >> slower. > >> Less elapsed time will show between an pair of events for the relatively > >> moving clock than an at-rest clock. That is independent of the direction > >> of > >> the relative motion. > > >> I had though we agreed to ignore illusions due to propagation delays. > > > Indeed, but when you started talking of the clocks "speeding up", that > > caused me confusion. > > Why? Just do not worry about optical illusions and concentrate on what is > actually going on. But you said the speeding up bit *is* a result of an optical illusion. You see how hard it is to get a straight but comprehensive answer here? > > would leave a small remainder of slowing, > > There would be the slowing SR predits. You are talking about additonal > optical illusions. No, I was talking about the slowing predicted by SR, which is not accounted for by the effects that we've both already agreed are "illusions". > > based on > > the relative speed between the clocks? (and not based on the direction > > of relative movement?) > > Yes. I've already said that. So what is the extent of the slowing, and on what variables does it depend? (We can speak in quantitative terms on this point.)
From: Ste on 10 Apr 2010 06:08
On 10 Apr, 09:01, "Inertial" <relativ...(a)rest.com> wrote: > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > news:a5efd3b8-2a31-4935-828b-234bb8569461(a)w17g2000yqj.googlegroups.com... > > > > > > > On 10 Apr, 07:44, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> > > wrote: > >> "Ste" <ste_ro...(a)hotmail.com> wrote in message > > >>news:da85279f-24ef-481b-93d0-287ce74db45d(a)y14g2000yqm.googlegroups.com... > > >> > On 10 Apr, 04:49, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> > >> > wrote: > >> >> I have some sympathy for your problem. I have no sympathy for the fact > >> >> that > >> >> instead of trying to understand how the Universe actually works, your > >> >> position is that SR is wrong and/or Inertial, PD and I am wrong > >> >> because > >> >> we > >> >> agree with SR and SR is wrong. > > >> > I do wish you'd stop framing the issue as "you're either with us or > >> > against us". There is obviously some validity to SR - and I've said it > >> > a million times. For us to argue about what explanation underlies SR, > >> > or how to interpret it, is not to say SR is "wrong". > > >> But you do say SR is wrong, all the time, because you argue with its > >> predictions. > > >> Lets see, for the record, whether you believe SR is wrong. > > >> Here are two specific predictions of SR. Tell me if you think they are > >> correct: > > >> 1. Two twins - one travels to a start 1 light year away at 0.9c, turns > >> around and returns at 0.9c. The travelling twin ages less than the stay > >> at > >> home because of relativistic time dilation. True of False? > > > True, because there is a "real" slowdown of the astronaut twin. > > If by 'slow down' you mean 'aged less' as per the question asked. > > Why do you have to continually introduce other terms like '"real" slowdown'? In order to distinguish from the speeding and slowing that are the result of "optical illusions", or to distinguish from a slowdown of the observer (as opposed to the object being measured). |