Wonderful!
in [Physics]
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From: mpc755 on 5 Jan 2010 12:10 On Jan 5, 12:05 pm, "papar...(a)gmail.com" <papar...(a)gmail.com> wrote: > On 5 ene, 13:42, mpc755 <mpc...(a)gmail.com> wrote: > > > > > On Jan 5, 11:21 am, "papar...(a)gmail.com" <papar...(a)gmail.com> wrote: > > > > On 5 ene, 12:28, mpc755 <mpc...(a)gmail.com> wrote: > > > > > On Jan 5, 10:04 am, "papar...(a)gmail.com" <papar...(a)gmail.com> wrote: > > > > > > On 5 ene, 10:45, mpc755 <mpc...(a)gmail.com> wrote: > > > > > > > On Jan 4, 8:47 pm, mpc755 <mpc...(a)gmail.com> wrote: > > > > > > > We can't go back to any math or anything else until we agree, or agree > > > > > > to disagree, with the above. > > > > > > > Forget the frames of reference for a second and just think about this > > > > > > logically from the perspective of an Observer on the boat and what it > > > > > > means to the Observer at M on the dock if the Observer on the boat > > > > > > concludes the cement blocks entered the water simultaneously as I have > > > > > > described above. > > > > > > > The Observer on the boat must determine the simultaneity of the cement > > > > > > blocks entering the water with respect to the water because the waves > > > > > > propagate through the water. > > > > > > > You really need to step back and understand the gedanken conceptually > > > > > > before jumping into the math. You first have to understand if the > > > > > > Observer on the boat determines the cement blocks entered the water > > > > > > simultaneously, and the cement blocks were equi-distant from the > > > > > > Observer at M on the dock when they entered the water, then the waves > > > > > > reach the Observer at M simultaneously. > > > > > > > You have to understand the waves do not have to reach the boat > > > > > > simultaneously for the Observer on the boat to determine the cements > > > > > > blocks entered the water simultaneously based on the available > > > > > > information. > > > > > > After hundreds of posts you still do not get the basic facts of > > > > > simultaneity. > > > > > When, in the train gedanken initial conditions, it is said "...Just > > > > > when the flashes of lightning occur (at points A and B on the > > > > > embankment frame), this point M' naturally coincides with the point M, > > > > > but it moves towards the right in the diagram with the velocity v of > > > > > the train...", you seem to believe that it means that, as points A and > > > > > A' also coincide (as well as points B and B'), the lightning strikes > > > > > were also simultaneous for points A' and B'. Actually this is wrong, > > > > > as it was clearly pointed out to you by Paul Draper. > > > > > In Special Relativity, time and length of moving objects are frame > > > > > dependent quantities. > > > > > In the numerical example I provided to you, this is clearly derived: > > > > > > Point A has x=-100000km and lightning strike was at t=0 sec > > > > > Point A' has x'=-125000km and lightning strike was at t'=+0.25sec > > > > > > Point B has x=+100000km and lightning strike was at t=0 sec > > > > > Point B' has x=+125000km and ligthning strike was at t'=-0.25sec > > > > > > With these initial values, observers saw the following: > > > > > > Observer M saw two simultaneous light signals at t=0.333sec > > > > > > Observer M' saw the light signal from point B at t'=0.167sec and the > > > > > light signal from point A at t'=0.667sec > > > > > > Simultaneity on frame K means non-simultaneity on the moving (relative > > > > > to K) frame K'. > > > > > > Miguel Rios > > > > > Just go back to the Observer on the boat and the cement blocks being > > > > dropped in front of the boat and off the back of the boat. The > > > > Observer on the boat knows the speed of the boat relative to the > > > > water, the speed the waves propagate through the water, the difference > > > > in time the wave hits the front of the boat and the wave hits the back > > > > of the boat, and how far from the boat the cement blocks were when the > > > > cement blocks entered the water. Is this enough information for the > > > > Observer on the boat to conclude the cement blocks entered the water > > > > simultaneously even if the waves the cement blocks make in the water > > > > do not reach the boat simultaneously? > > > > > Of course it is. > > > > No it is not enough in Special Relativity, since both time and length > > > quantities are frame dependent. Observer M saw and calculated both > > > strikes were simultaneous. Observer M' saw and calculated both strikes > > > were not simultaneous. > > > > Miguel Rios > > > I'm not talking about the Observer at M or the Observer at M'. I'm > > simply discussing an Observer on a boat who knows the following: > > So now you are not discussing anymore Einstein's train gedanken!! > > > - The speed of the boat relative to the water. > > Badly put, since for these type of thought experiments you must > consider inertial objects, then your observer on the boat does not > know if it is the boat which is moving, with respect to a given > reference point on the water or, viceversa, is the water which moves > at the given speed (with a minus sign) with respect to the boat. In > other words, that observer on the boat should at least consider both > cases (observations would also be compatible with both the boat and > the water moving with respect to each other at a given time which > opens the number to infinity). > - The Observer knows the water is at rest with respect to the shore. The observer knows the boat is moving relative to the entry points of the cement blocks into the water. > > - The speed at which the waves the cement blocks make propagate > > through the water. > > OK with this > > > - The difference in time the wave from the cement block dropped off > > the bow of the boat hits the front of the boat and the wave from the > > cement block dropped off the stern of the boat hits the back of the > > boat. > > OK with this, since these are observations > > > - The distance the cement blocks were from the boat when the cement > > blocks entered the water. > > This I doubt you will be able to measure in a reliable way, unless you > somehow know beforehand the geometry of the experiment, which you have > not defined. > The Observer knows the cement blocks were dropped from 100ft outriggers off the front and back of the boat. > > Is this enough information for the Observer on the boat to conclude > > the cement blocks entered the water simultaneously even if the waves > > the cement blocks make in the water do not reach the boat > > simultaneously? > > No for a long shot, according to the observer defined knowledge. > > > Of course it is. > > Of course it is not enough. It is evident that Einstein was far more > clever and clearer than you in formulating these thought experiments. > > Miguel Rios Of course it is enough information.
From: paparios on 5 Jan 2010 12:34 On 5 ene, 14:10, mpc755 <mpc...(a)gmail.com> wrote: > On Jan 5, 12:05 pm, "papar...(a)gmail.com" <papar...(a)gmail.com> wrote: > > > I'm not talking about the Observer at M or the Observer at M'. I'm > > > simply discussing an Observer on a boat who knows the following: > > > So now you are not discussing anymore Einstein's train gedanken!! > > > > - The speed of the boat relative to the water. > > > Badly put, since for these type of thought experiments you must > > consider inertial objects, then your observer on the boat does not > > know if it is the boat which is moving, with respect to a given > > reference point on the water or, viceversa, is the water which moves > > at the given speed (with a minus sign) with respect to the boat. In > > other words, that observer on the boat should at least consider both > > cases (observations would also be compatible with both the boat and > > the water moving with respect to each other at a given time which > > opens the number to infinity). > > - The Observer knows the water is at rest with respect to the shore. > The observer knows the boat is moving relative to the entry points of > the cement blocks into the water. > So now we have a shore entering the gedanken?. You are making stuff as it suits you, right? Well, with shore or no shore, with naked or not naked women on that shore, the objection stands. The observer on the boat does not know who is moving: the boat with respect to the water/shore/naked women at a speed v, or the water/shore/naked women with respect to the boat at a speed -v. But it is also possible that, with respect to the center of the Galaxy (if you introduce a shore, let us keeping introducing things) the boat is moving at a speed v/2 while the water/shore/naked women is moving at a speed -v/2. > > > > - The distance the cement blocks were from the boat when the cement > > > blocks entered the water. > > > This I doubt you will be able to measure in a reliable way, unless you > > somehow know beforehand the geometry of the experiment, which you have > > not defined. > > The Observer knows the cement blocks were dropped from 100ft > outriggers off the front and back of the boat. > So you are saying that both cement blocks were simultaneously dropped from the boat, right? So what is the point of considering this water/ shore/naked women thing in your gedanken. The boat observer already knows that. > > > Is this enough information for the Observer on the boat to conclude > > > the cement blocks entered the water simultaneously even if the waves > > > the cement blocks make in the water do not reach the boat > > > simultaneously? > For your purpose, this is redundant information. The cement blocks were dropped from the boat simultaneously, probably under command of the boat observer. You are not giving any relevance to the observation of both waves arriving at different times. Bad gedanken. Miguel Rios
From: mpc755 on 5 Jan 2010 12:56 On Jan 5, 12:34 pm, "papar...(a)gmail.com" <papar...(a)gmail.com> wrote: > On 5 ene, 14:10, mpc755 <mpc...(a)gmail.com> wrote: > > > > > On Jan 5, 12:05 pm, "papar...(a)gmail.com" <papar...(a)gmail.com> wrote: > > > > I'm not talking about the Observer at M or the Observer at M'. I'm > > > > simply discussing an Observer on a boat who knows the following: > > > > So now you are not discussing anymore Einstein's train gedanken!! > > > > > - The speed of the boat relative to the water. > > > > Badly put, since for these type of thought experiments you must > > > consider inertial objects, then your observer on the boat does not > > > know if it is the boat which is moving, with respect to a given > > > reference point on the water or, viceversa, is the water which moves > > > at the given speed (with a minus sign) with respect to the boat. In > > > other words, that observer on the boat should at least consider both > > > cases (observations would also be compatible with both the boat and > > > the water moving with respect to each other at a given time which > > > opens the number to infinity). > > > - The Observer knows the water is at rest with respect to the shore. > > The observer knows the boat is moving relative to the entry points of > > the cement blocks into the water. > > So now we have a shore entering the gedanken?. You are making stuff as > it suits you, right? > Well, with shore or no shore, with naked or not naked women on that > shore, the objection stands. The observer on the boat does not know > who is moving: the boat with respect to the water/shore/naked women at > a speed v, or the water/shore/naked women with respect to the boat at > a speed -v. But it is also possible that, with respect to the center > of the Galaxy (if you introduce a shore, let us keeping introducing > things) the boat is moving at a speed v/2 while the water/shore/naked > women is moving at a speed -v/2. > - The Observer on the boat knows it is the boat moving relative to the shore. - The Observer on the boat knows the water is at rest with respect to the shore. - The Observer on the boat knows the boat is moving relative to the water at rest with respect to the shore. > > > > > > - The distance the cement blocks were from the boat when the cement > > > > blocks entered the water. > > > > This I doubt you will be able to measure in a reliable way, unless you > > > somehow know beforehand the geometry of the experiment, which you have > > > not defined. > > > The Observer knows the cement blocks were dropped from 100ft > > outriggers off the front and back of the boat. > > So you are saying that both cement blocks were simultaneously dropped > from the boat, right? So what is the point of considering this water/ > shore/naked women thing in your gedanken. The boat observer already > knows that. > The Observer does not see the cement blocks enter the water. The Observer on the boat has to calculate if the cement blocks enter the water simultaneously based on the information I have been describing. > > > > Is this enough information for the Observer on the boat to conclude > > > > the cement blocks entered the water simultaneously even if the waves > > > > the cement blocks make in the water do not reach the boat > > > > simultaneously? > > For your purpose, this is redundant information. The cement blocks > were dropped from the boat simultaneously, probably under command of > the boat observer. You are not giving any relevance to the observation > of both waves arriving at different times. Bad gedanken. > > Miguel Rios I guess we have to start at the very basics then. The Observer on the boat releases a latch which allows the cement blocks to hit the water simultaneously. Is the Observer on the boat able to conclude the cement blocks entered the water simultaneously even though the wave from the cement block dropped off the front of the boat reaches the boat prior to the wave from the cement block dropped off the back of the boat? Let's assume you at least agree to this. The Captain on the boat noted the time difference between the wave hitting the front of the boat and the wave hitting the back of the boat. Now, the latch is modified so the cement blocks can be dropped non- simultaneously and a different Observer is going to pull the latches. The Captain is below deck when the latches are thrown and the cement blocks enter the water. The Captain below deck arrives on deck to detect the wave hitting the front of the boat and then the wave hitting the back of the boat. Everything is the same as the previous experiment in terms of the speed of the boat and the length of the outriggers and so forth. The time difference between the wave hitting the front of the boat and the wave hitting the back of the boat is the same as when the Captain pulled the lever in the first experiment and watched the cement blocks hit the water simultaneously. Even though the Captain did not see the cement blocks hit the water simultaneously this time, is the Captain able to determine the cement blocks hit the water simultaneously this time because the waves hit the boat the same time apart as the first experiment?
From: paparios on 5 Jan 2010 13:33 On 5 ene, 14:56, mpc755 <mpc...(a)gmail.com> wrote: > On Jan 5, 12:34 pm, "papar...(a)gmail.com" <papar...(a)gmail.com> wrote: > > > > > > > On 5 ene, 14:10, mpc755 <mpc...(a)gmail.com> wrote: > > > > On Jan 5, 12:05 pm, "papar...(a)gmail.com" <papar...(a)gmail.com> wrote: > > > > > I'm not talking about the Observer at M or the Observer at M'. I'm > > > > > simply discussing an Observer on a boat who knows the following: > > > > > So now you are not discussing anymore Einstein's train gedanken!! > > > > > > - The speed of the boat relative to the water. > > > > > Badly put, since for these type of thought experiments you must > > > > consider inertial objects, then your observer on the boat does not > > > > know if it is the boat which is moving, with respect to a given > > > > reference point on the water or, viceversa, is the water which moves > > > > at the given speed (with a minus sign) with respect to the boat. In > > > > other words, that observer on the boat should at least consider both > > > > cases (observations would also be compatible with both the boat and > > > > the water moving with respect to each other at a given time which > > > > opens the number to infinity). > > > > - The Observer knows the water is at rest with respect to the shore. > > > The observer knows the boat is moving relative to the entry points of > > > the cement blocks into the water. > > > So now we have a shore entering the gedanken?. You are making stuff as > > it suits you, right? > > Well, with shore or no shore, with naked or not naked women on that > > shore, the objection stands. The observer on the boat does not know > > who is moving: the boat with respect to the water/shore/naked women at > > a speed v, or the water/shore/naked women with respect to the boat at > > a speed -v. But it is also possible that, with respect to the center > > of the Galaxy (if you introduce a shore, let us keeping introducing > > things) the boat is moving at a speed v/2 while the water/shore/naked > > women is moving at a speed -v/2. > > - The Observer on the boat knows it is the boat moving relative to the > shore. > - The Observer on the boat knows the water is at rest with respect to > the shore. > - The Observer on the boat knows the boat is moving relative to the > water at rest with respect to the shore. > > > > > > > > > > > > - The distance the cement blocks were from the boat when the cement > > > > > blocks entered the water. > > > > > This I doubt you will be able to measure in a reliable way, unless you > > > > somehow know beforehand the geometry of the experiment, which you have > > > > not defined. > > > > The Observer knows the cement blocks were dropped from 100ft > > > outriggers off the front and back of the boat. > > > So you are saying that both cement blocks were simultaneously dropped > > from the boat, right? So what is the point of considering this water/ > > shore/naked women thing in your gedanken. The boat observer already > > knows that. > > The Observer does not see the cement blocks enter the water. The > Observer on the boat has to calculate if the cement blocks enter the > water simultaneously based on the information I have been describing. > > > > > > Is this enough information for the Observer on the boat to conclude > > > > > the cement blocks entered the water simultaneously even if the waves > > > > > the cement blocks make in the water do not reach the boat > > > > > simultaneously? > > > For your purpose, this is redundant information. The cement blocks > > were dropped from the boat simultaneously, probably under command of > > the boat observer. You are not giving any relevance to the observation > > of both waves arriving at different times. Bad gedanken. > > > Miguel Rios > > I guess we have to start at the very basics then. The Observer on the > boat releases a latch which allows the cement blocks to hit the water > simultaneously. Is the Observer on the boat able to conclude the > cement blocks entered the water simultaneously even though the wave > from the cement block dropped off the front of the boat reaches the > boat prior to the wave from the cement block dropped off the back of > the boat? > > Let's assume you at least agree to this. > > The Captain on the boat noted the time difference between the wave > hitting the front of the boat and the wave hitting the back of the > boat. > > Now, the latch is modified so the cement blocks can be dropped non- > simultaneously and a different Observer is going to pull the latches. > > The Captain is below deck when the latches are thrown and the cement > blocks enter the water. The Captain below deck arrives on deck to > detect the wave hitting the front of the boat and then the wave > hitting the back of the boat. > > Everything is the same as the previous experiment in terms of the > speed of the boat and the length of the outriggers and so forth. > > The time difference between the wave hitting the front of the boat and > the wave hitting the back of the boat is the same as when the Captain > pulled the lever in the first experiment and watched the cement blocks > hit the water simultaneously. Even though the Captain did not see the > cement blocks hit the water simultaneously this time, is the Captain > able to determine the cement blocks hit the water simultaneously this > time because the waves hit the boat the same time apart as the first > experiment? More new additions to your gedanken assumptions? The point is your poor gedanken proofs nothing and, furthermore, it is useless to determine the relativity of simultaneity, while Einstein's single pharagraph does it quite fast and clear: "...When we say that the lightning strokes A and B are simultaneous with respect to the embankment, we mean: the rays of light emitted at the places A and B, where the lightning occurs, meet each other at the mid-point M of the length A > B of the embankment. But the events A and B also correspond to positions A and B on the train. Let M' be the mid-point of the distance A > B on the travelling train. Just when the flashes of lightning occur, this point M' naturally coincides with the point M, but it moves towards the right in the diagram with the velocity v of the train. If an observer sitting in the position M in the train did not possess this velocity, then he would remain permanently at M, and the light rays emitted by the flashes of lightning A and B would reach him simultaneously, i.e. they would meet just where he is situated. Now in reality (considered with reference to the railway embankment) he is hastening towards the beam of light coming from B, whilst he is riding on ahead of the beam of light coming from A. Hence the observer will see the beam of light emitted from B earlier than he will see that emitted from A. Observers who take the railway train as their reference-body must therefore come to the conclusion that the lightning flash B took place earlier than the lightning flash A..." I'm afraid you will have to go back to the thought experiment design room. Miguel Rios
From: mpc755 on 5 Jan 2010 13:45
On Jan 5, 1:33 pm, "papar...(a)gmail.com" <papar...(a)gmail.com> wrote: > On 5 ene, 14:56, mpc755 <mpc...(a)gmail.com> wrote: > > > > > On Jan 5, 12:34 pm, "papar...(a)gmail.com" <papar...(a)gmail.com> wrote: > > > > On 5 ene, 14:10, mpc755 <mpc...(a)gmail.com> wrote: > > > > > On Jan 5, 12:05 pm, "papar...(a)gmail.com" <papar...(a)gmail.com> wrote: > > > > > > I'm not talking about the Observer at M or the Observer at M'. I'm > > > > > > simply discussing an Observer on a boat who knows the following: > > > > > > So now you are not discussing anymore Einstein's train gedanken!! > > > > > > > - The speed of the boat relative to the water. > > > > > > Badly put, since for these type of thought experiments you must > > > > > consider inertial objects, then your observer on the boat does not > > > > > know if it is the boat which is moving, with respect to a given > > > > > reference point on the water or, viceversa, is the water which moves > > > > > at the given speed (with a minus sign) with respect to the boat. In > > > > > other words, that observer on the boat should at least consider both > > > > > cases (observations would also be compatible with both the boat and > > > > > the water moving with respect to each other at a given time which > > > > > opens the number to infinity). > > > > > - The Observer knows the water is at rest with respect to the shore.. > > > > The observer knows the boat is moving relative to the entry points of > > > > the cement blocks into the water. > > > > So now we have a shore entering the gedanken?. You are making stuff as > > > it suits you, right? > > > Well, with shore or no shore, with naked or not naked women on that > > > shore, the objection stands. The observer on the boat does not know > > > who is moving: the boat with respect to the water/shore/naked women at > > > a speed v, or the water/shore/naked women with respect to the boat at > > > a speed -v. But it is also possible that, with respect to the center > > > of the Galaxy (if you introduce a shore, let us keeping introducing > > > things) the boat is moving at a speed v/2 while the water/shore/naked > > > women is moving at a speed -v/2. > > > - The Observer on the boat knows it is the boat moving relative to the > > shore. > > - The Observer on the boat knows the water is at rest with respect to > > the shore. > > - The Observer on the boat knows the boat is moving relative to the > > water at rest with respect to the shore. > > > > > > > - The distance the cement blocks were from the boat when the cement > > > > > > blocks entered the water. > > > > > > This I doubt you will be able to measure in a reliable way, unless you > > > > > somehow know beforehand the geometry of the experiment, which you have > > > > > not defined. > > > > > The Observer knows the cement blocks were dropped from 100ft > > > > outriggers off the front and back of the boat. > > > > So you are saying that both cement blocks were simultaneously dropped > > > from the boat, right? So what is the point of considering this water/ > > > shore/naked women thing in your gedanken. The boat observer already > > > knows that. > > > The Observer does not see the cement blocks enter the water. The > > Observer on the boat has to calculate if the cement blocks enter the > > water simultaneously based on the information I have been describing. > > > > > > > Is this enough information for the Observer on the boat to conclude > > > > > > the cement blocks entered the water simultaneously even if the waves > > > > > > the cement blocks make in the water do not reach the boat > > > > > > simultaneously? > > > > For your purpose, this is redundant information. The cement blocks > > > were dropped from the boat simultaneously, probably under command of > > > the boat observer. You are not giving any relevance to the observation > > > of both waves arriving at different times. Bad gedanken. > > > > Miguel Rios > > > I guess we have to start at the very basics then. The Observer on the > > boat releases a latch which allows the cement blocks to hit the water > > simultaneously. Is the Observer on the boat able to conclude the > > cement blocks entered the water simultaneously even though the wave > > from the cement block dropped off the front of the boat reaches the > > boat prior to the wave from the cement block dropped off the back of > > the boat? > > > Let's assume you at least agree to this. > > > The Captain on the boat noted the time difference between the wave > > hitting the front of the boat and the wave hitting the back of the > > boat. > > > Now, the latch is modified so the cement blocks can be dropped non- > > simultaneously and a different Observer is going to pull the latches. > > > The Captain is below deck when the latches are thrown and the cement > > blocks enter the water. The Captain below deck arrives on deck to > > detect the wave hitting the front of the boat and then the wave > > hitting the back of the boat. > > > Everything is the same as the previous experiment in terms of the > > speed of the boat and the length of the outriggers and so forth. > > > The time difference between the wave hitting the front of the boat and > > the wave hitting the back of the boat is the same as when the Captain > > pulled the lever in the first experiment and watched the cement blocks > > hit the water simultaneously. Even though the Captain did not see the > > cement blocks hit the water simultaneously this time, is the Captain > > able to determine the cement blocks hit the water simultaneously this > > time because the waves hit the boat the same time apart as the first > > experiment? > > More new additions to your gedanken assumptions? > > The point is your poor gedanken proofs nothing and, furthermore, it is > useless to determine the relativity of simultaneity, while Einstein's > single pharagraph does it quite fast and clear: > > "...When we say that the lightning strokes A and B are simultaneous > with respect to the embankment, we mean: the rays of light emitted at > the places A and B, where the lightning occurs, meet each other at the > mid-point M of the length A > B of the embankment. But the events A > and B also correspond to positions A and B on the train. Let M' be the > mid-point of the distance A > B on the travelling train. Just when > the flashes of lightning occur, this point M' naturally coincides with > the point M, but it moves towards the right in the diagram with the > velocity v of the train. If an observer sitting in the position M in > the train did not possess this velocity, then he would remain > permanently at M, and the light rays emitted by the flashes of > lightning A and B would reach him simultaneously, i.e. they would meet > just where he is situated. Now in reality (considered with reference > to the railway embankment) he is hastening towards the beam of light > coming from B, whilst he is riding on ahead of the beam of light > coming from A. Hence the observer will see the beam of light emitted > from B earlier than he will see that emitted from A. Observers who > take the railway train as their reference-body must therefore come to > the conclusion that the lightning flash B took place earlier than the > lightning flash A..." > > I'm afraid you will have to go back to the thought experiment design > room. > > Miguel Rios The Captain pulls the lever and watches the cement blocks hit the water simultaneously and notes the time difference between the wave hitting the front of the boat and the wave hitting the back of the boat. The next time the Captain pulls the lever and closes her eyes. The Captain opens her eyes to see the waves hit the front and back of the boat the same time interval apart as when the Captain watched the waves enter the water simultaneously. You are saying, even though the Captain knows the waves hit the boat the same interval apart as the first time the experiment was executed, since the Captain closed her eyes, the Captain is unable to determine the simultaneity of the blocks entering the water? You're joking, right? |