Wonderful!
in [Physics]
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From: mpc755 on 16 Dec 2009 21:56 On Dec 16, 5:01 pm, mpc755 <mpc...(a)gmail.com> wrote: > On Dec 16, 4:46 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Dec 16, 2:14 pm, mpc755 <mpc...(a)gmail.com> wrote: > > > > On Dec 16, 3:09 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Dec 16, 12:51 pm, mpc755 <mpc...(a)gmail.com> wrote: > > > > > > On Dec 16, 11:30 am, mpc755 <mpc...(a)gmail.com> wrote: > > > > > > > Ok, so let's not talk about frames of reference. The train is 100 > > > > > > billion light years away from the embankment. Is it physically > > > > > > possible for the light from lightning strikes at A' and B' to reach M' > > > > > > simultaneously as determined by an Observer at M' on the train and is > > > > > > it physically possible for the light from lightning strikes at A and B > > > > > > to reach M simultaneously as determined by an Observer at M if the > > > > > > train and the embankment are 100 billion light years apart and A and B > > > > > > are 1 mile each from M and A' and B' are one mile each from M'? > > > > > > Let's assume logic prevails and if the train and the embankment are > > > > > 100 billion light years apart, light from lightning strikes at A' and > > > > > B' can reach M' simultaneously as determined by an Observer at M' and > > > > > light from lightning strikes at A and B can reach M simultaneously as > > > > > determined by an Observer at M. > > > > > > So, when does SR 'kick in'? > > > > > > For some reason, in SR, in my animation, the train and the embankment > > > > > are too close to each other even though both exist in their own > > > > > regions of three dimensional space: > > > > > You apparently don't understand the train and the embankment scenario > > > > that Einstein was proposing. > > > > In that scenario, there are only TWO lightning strikes, not FOUR. > > > > > And you are wrong in thinking there are two frames that live in > > > > isolated regions of three-dimensional space. You have the impression > > > > that the train frame is the space inside the train and the embankment > > > > frame is the space outside the train. That is not what a frame of > > > > reference is. > > > > > >http://www.youtube.com/watch?v=jyWTaXMElUk > > > > > > For some reason, in SR, in my animation, the light from the lightning > > > > > strikes at A' and B' cannot reach M' simultaneously as determined by > > > > > an Observer at M' AND the light from the lightning strikes at A and B > > > > > cannot reach M simultaneously as determined by an Observer at M. > > > > > In SR's train and embankment scenario, there are only TWO lightning > > > > strikes, not four. > > > > In SR's train and embankment scenario? > > > > You mean in Einstein's train and embankment scenario. > > > > I'm saying the SR interpretation of my animation where there are four > > > lightning strikes. > > > Your animation -- which has the strikes at A' and B' occurring > > simultaneously in the rest frame of A, B, and M -- also has the light > > from those strikes arriving at M' simultaneously. This does not happen > > in nature, experimentally. > > Incorrect. If you perform the experiment where water is at rest > relative to the embankment and water is at rest relative to the train > and the embankment and the train occupy different regions of three > dimensional space, then my animation is correct. It doesn't matter how > close the train is to the embankment, as long as the water is at rest > relative to both the train and the embankment, the light from A and B > will reach M simultaneously and the light from A' and B' will reach M' > simultaneously, in nature. > Let's take this to the next step. The membrane between the train and the embankment allows the light to travel from the train to the embankment and vice verse. The light emitted from the lightning strike at A' travels through the water on the train. Some of the light passes through the membrane, travels through the water on the embankment and travels to the Observer at M. When the Observer at M determines when the lightning strike occurred at A', the Observer at M factors in the moving train, the water at rest on the train, the membrane, the water at rest on the embankment, and where A' *is* when the light reaches M. When the Observer at M' determines when the lightning strike occurred at A', the Observer at M' factors in the water at rest on the train and where A' *is* when the light reaches M'. Both Observers come to the same conclusion as to when the lightning strike occurred at A'.
From: GogoJF on 16 Dec 2009 22:05 On Dec 16, 5:03 pm, moro...(a)world.std.spaamtrap.com (Michael Moroney) wrote: > mpc755 <mpc...(a)gmail.com> writes: > >The train and embankment are 1 millimeter apart. A and A' are 1 > >millimeter apart, B and B' are 1 millimeter apart and M and M' are 1 > >millimeter apart at the time of the lightning strikes. A and B are 1 > >light year from M and A' and B' are 1 light year from M'. The train > >and embankment are moving at 1/4 the speed of light relative to one > >another. > ... > >Once there is only one knee-deep pool of water, and a single lightning > >strike at A/A' and a single lightning strike at B/B', where the light > >originates from and how the light travels depends upon which frame of > >reference the pool of water is at rest relative to. If the knee-deep > >pool of water is at rest relative to the embankment, measuring to the > >marks left on the train in order to determine where the light traveled > >from to M' is meaningless. Likewise, if the knee-deep pool of water is > >at rest relative to the train, measuring to the marks left on the > >embankment in order to determine where the light traveled from to M is > >meaningless. > > Now you're getting stupid trying to get your aether to be at rest in > all frames to explain light moving at c in all frames. But I'll have > fun with it. Someone on board the train (moving at 1/4 c) shines a light > beam toward the embankment at a right angle to the train motion. > 1) What is the velocity of the light beam relative to the aether, when > it's still travelling through the train? > 2) What is the velocity of the light beam relative to the aether, after > it has passed through the window of the train and it is now passing through > the aether of the embankment? > 3) What will someone on the embankment measuring the velocity of the beam > measure for its velocity? > > Now, the light is at one end of the train, A'. The light beam is aimed > almost toward B', but not quite. It is offset a tiny angle epsilon, > toward the embankment. (since the train is 2 light years long [A'-M'-B'] > but only 1 mm from the embankment, epsilon can be _very_ tiny) There is an > open window along its path. > > 1) What is the velocity of the light beam relative to the aether, when > it's still travelling through the train? > 2) What is the velocity of the light beam relative to the aether, after > it has passed through the window of the train and it is now passing through > the aether of the embankment? > 3) What will someone on the embankment measuring the velocity of the beam > measure for its velocity? Michael, can you name me a situation, where there is such a phenomenon, which travels at 1/4 c?
From: Michael Moroney on 16 Dec 2009 22:08 mpc755 <mpc755(a)gmail.com> writes: >On Dec 16, 8:34=A0pm, moro...(a)world.std.spaamtrap.com (Michael Moroney) >wrote: >> >> >> 1) What is the velocity of the light beam relative to the aether, when >> >> it's still travelling through the train? >> >Light travels at 'c' relative to the aether. >> >> OK. Since the angle is so small we can ignore the small effects of >> sin/cos of it being different from 0/1. So... the platform observer will >> see the light on the train moving at either 1.25 c or 0.75 c >The platform observer does not 'see the light on the train'. That is >one of the biggest misconceptions of light. You don't watch light >propagate like a thrown baseball. What you 'see' is light when it hits >your eye. That's why I added the 'dust' to the train. Some of the laser going from the back to the front would be scattered by the dust, so that the embankment observer could see the laser pulse propagate. Or, to put it another way. A 1 light year long train, travelling at c/4. When the front of the train is 1/4 light year away, the rear of the train is 1 1/4 light year away. At that time, a laser is fired from the rear to the front. One year later, the front of the train reaches the embankment observer since it was travelling at c/4 and was 1/4 light year away. At the same time, the laser pulse reaches the front of the train since it was travelling a distance of 1 light year for one year. Therefore, as far as the trackside observer is concerned, the light travelled 1 1/4 light year in 1 year, or 1.25 c. If firing the laser pulse also triggered a trackside laser firing along the track, light from it wouldn't reach us for another 3 months since it was 1 1/4 light year away. Light faster than light.
From: Michael Moroney on 16 Dec 2009 22:23 GogoJF <jfgogo22(a)yahoo.com> writes: >Michael, can you name me a situation, where there is such a >phenomenon, which travels at 1/4 c? This is a mutation of Albert Einstein's famous train thought experiment which he used to help explain special relativity. It involves imagining a train passing a platform at a relativistic speed and when the middle of the train passes an observer on the platform, the observer sees lightning bolts strike the front and rear of the train simultaneously. What does a second observer in the middle of the train (and on it) observe? mpc755 doesn't understand the thought experiment and think jhe has his own answer to what happens. There is, of course, no such train.
From: mpc755 on 16 Dec 2009 22:32
On Dec 16, 10:08 pm, moro...(a)world.std.spaamtrap.com (Michael Moroney) wrote: > mpc755 <mpc...(a)gmail.com> writes: > >On Dec 16, 8:34=A0pm, moro...(a)world.std.spaamtrap.com (Michael Moroney) > >wrote: > > >> >> 1) What is the velocity of the light beam relative to the aether, when > >> >> it's still travelling through the train? > >> >Light travels at 'c' relative to the aether. > > >> OK. Since the angle is so small we can ignore the small effects of > >> sin/cos of it being different from 0/1. So... the platform observer will > >> see the light on the train moving at either 1.25 c or 0.75 c > >The platform observer does not 'see the light on the train'. That is > >one of the biggest misconceptions of light. You don't watch light > >propagate like a thrown baseball. What you 'see' is light when it hits > >your eye. > > That's why I added the 'dust' to the train. Some of the laser going from > the back to the front would be scattered by the dust, so that the > embankment observer could see the laser pulse propagate. > But the light which is reflected by the dust is still going to travel through the aether which is at rest relative to the embankment. You're still not 'seeing the light propagate on the train'. What you are 'seeing' is light reflected by dust particles traveling at 'c' relative to the aether. > Or, to put it another way. A 1 light year long train, travelling at c/4. > When the front of the train is 1/4 light year away, the rear of the train > is 1 1/4 light year away. At that time, a laser is fired from the rear to > the front. One year later, the front of the train reaches the embankment > observer since it was travelling at c/4 and was 1/4 light year away. At > the same time, the laser pulse reaches the front of the train since it was > travelling a distance of 1 light year for one year. Therefore, as far as > the trackside observer is concerned, the light travelled 1 1/4 light year > in 1 year, or 1.25 c. Again, this is incorrect. In your gadenken, I'm assuming the aether is at rest relative to the train. When the light reaches the Observer on the embankment, the light has traveled from where the back of the train *is*. The light has traveled 1 light year from where the back of the train *is* to where the Observer on the embankment is. Since the aether is at rest relative to the train, where the lightning strike occurred in three dimensional space relative to the Observer on the embankment is meaningless. Light travels at 'c' relative to the aether. I don't know how else to explain this but with flashes of light in water. There is a round pool on the train. The side of the pool is made of glass. There are Observers on the train with their faces pushed up against the glass. There is an Observer on the embankment. A flash goes off in the middle of the pool. It just so happens when the flash travels through the water, travels through the glass, and is about to reach the Observers on the train, the pool is right next to the Observer on the embankment. The Observer on the embankment presses his face against the glass just like the Observers on the train do. The light travels the same distance to ALL of the Observers. The light has traveled from where the center of the pool *is* to where the Observers on the train *are* when the Observers on the train see the light. The light has traveled from where the center of the pool *is* to where the Observer on the embankment *is* when the Observer on the embankment sees the light. The light has traveled relative to the water which is at rest relative to the train. In your gadenken, since I am assuming the aether is at rest relative to the train, the light has traveled at 'c' relative to the aether which is at rest relative to the train. In you gadenken, if an Observer on the embankment and an Observer on the train are standing side by side when the light reaches both of them, the light has traveled the same distance to each of them because the light is traveling relative to the aether, and besides the last instant where the light is no longer on the train but on the embankment right before it reaches the Observer on the embankment, the light had traveled through the aether which is at rest relative to the train. |