Ballistic Theory, Progress report...Suitable for 5yo Kids
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From: Jeff Root on 15 Sep 2005 17:12 Jim Greenfield replied to George Dishman: >> To the person on the car, the car is not moving but >> the Earth, Sun, galaxies and clusters are moving. >> You speak about "net motion" as if it had some other >> meaning but it just means combining several, for >> example combining the motion of the galaxies relative >> to the Sun to that of the Sun relative to the railcar >> to get the motion of the galaxies relative to the >> railcar. > > The old chestnut! If I could plot the center of the universe, > with a good enough computer, FoRs become redundant, because > ALL calculations to be made from there. :-( A computer isn't needed. The ability to see the entire Universe is needed. No edge has been seen, so if there is a center, it might be anywhere-- even someplace beyond our ability see. But the center of the Universe would be an arbitrary reference point, no better than any other. If the Universe changes shape, the center could move around, anyway. >> In the first situation, the light moves vertically >> from the ceiling to the floor and through the hole. >> It goes on to hit the centre of the Earth which is >> directly below at all times. In the second scenario, >> the light moves vertically from the ceiling to the >> floor and through the hole. > > No. From the instant photon leaves bulb, it is going to > miss earth center. George didn't say it wouldn't. You never said what you mean by "vertical". > Hole in floor hasn't much to do with anything- all I was > trying to show is that photon path is altered by train > motion, and travels a longer (diagonal) path through the > universe, whether the passenger is aware of that, or not. Relative to the railcar, the light moves vertically. Relative to the Earth, it moves diagonally. > Smack for Jeff! > He says the clocks of passenger (pa) and platform > observer (po) are operating together. Wrong. I never said any such thing. You keep changing the names for things, and when you change them they usually don't improve any. "pa" and "po" have the advantage of brevity, but are much too easily confused, which is completely avoidable. > I am not referring to acceleration- ONLY velocity. > Remember, the pa fell asleep. This is important, and > goes back to our discussions on doppler (trains) > Detecting acceleration is a given (?), it is the v > under discussion. You say that the passenger failed to detect acceleration because he was asleep, and that detecting acceleration is a given. What conclusion can be drawn from those two assertions? > Think on the scenario for Lorentz contraction due to velocity. > Engine driver shines a beam back down the moving (forward)train. > As the rear is coming on to meet the beam, he deduces that the > train has shrunk, as c was the same as for a stationary train. Wrong. If you are going to apply the Lorentz transforms, you have to apply them correctly. No change in the train or in the light beam will be detected. > The guard shines his beam forward; as the engine is going > AWAY FROM the beam, HE deduces that the train has STRETCHED. Same error. > Nothing happens to the train!!!!!!!!!!! According to special relativity. Correct. > BOTH are victims of illusion, They see no illusion. > and when doing their calculations later, should realise that > their motion DID NOT CEASE when their respective flashes were > sent. They don't need to do any calculations to determine whether the train suddenly stopped. -- Jeff, in Minneapolis
From: Jeff Root on 15 Sep 2005 19:52 Jim Greenfield replied to Jeff Root: You deleted this question without answering it: | What gives you the idea that the person on the train has | been tricked or is mistaken about the true situation? | He sees the light go from the ceiling straight down to the | floor, and that is exactly what happens. What makes you think the passenger on the train would be mistaken about the train's motion relative to the Earth? That seems to be central to your argument, but you have given no reason for it. >> I've never used the term "time dilation", and I don't know >> whether Einstein did, either. It is used to describe the >> effects of relative motion on measurements, and I suspect >> it can be misleading. I will assume that it represents the >> relation t' = (t-((v/c^2)*x))/SQRT(1-(v^2/c^2)), in which >> case I have no problem with it. > > .and gravity! Huh? Gravity is in the domain of general relativity. We're talking about SR. The Lorentz transforms don't say anything about the effects of gravity. > But you are in conflict with your teacher, because George > says perfect clocks measure different intervals for the > SAME event. (flash from ceiling to floor) You were mistaken in thinking I said that clocks measure the same time interval if they are moving relative to each other. >> > because the passenger sees a different length path for the >> > light, than does a trackside observer (longer therefore more >> > time elapsed for photon journey when train moving on track). >> > Here we have established that the passenger was mistaken, >> > due to lack of information; >> >> No, you haven't established any such thing. The passenger >> sees a path straight down from the ceiling to the floor, >> and the trackside observer sees a longer, diagonal path >> from the ceiling to the floor. Both observations are 100% >> correct and accurate. > > if that photon was a ball, would both measure it to have the > same kinetic energy? No. the kinetic energy relative to the observer on the ground is greater than the kinetic energy relative to the passenger on the train. Similarly, the energy of a photon relative to the observer on the ground is greater than the energy of that same photon relative to the passenger. >> > when appraised of the true situation (that the passenger >> > slept through the accelleration), both observers agree that >> > there were NO alterations to time taken from ceiling to floor, >> > because in the moving scenario, both agree the light travels >> > the diagonal (longer), and takes the SAME amount of time to do >> > so, because it is moving faster. (see "Jim's Motion Detector") >> >> No, the trackside observer does not see the light move >> faster. He still sees the light move at c. > > Good. Then he will stop his watch when the photon strikes the > floor, which will be AFTER (his identical clock) that shown on > the passengers. The two clocks do not remain synchronized. >> The trackside observer agrees that the passenger sees a >> short, straight-down path, which takes a short time for >> the light to travel. > > Why? He can only know what pa tells him; he can't see inside > the van. In that case, the person standing on the ground isn't observing anything, and contributes nothing to the thought experiment. The thought experiment is then purposeless. You still didn't answer these questions clearly: >> >> Next, WHY was the train rider sure the beam was vertical >> >> relative to the Earth? You didn't say. What observation >> >> was his belief based on? You didn't say. If the rider >> >> could not see outside the car, and had no knowledge of >> >> whether it was moving or not, then surely he would know >> >> that he could *not* know whether the beam was vertical >> >> relative to the Earth. Do you agree? and my previous request for clarification: | Why would the passenger think he is stationary wrt the | ground? If he can't see out the window, and doesn't know | whether the train is moving wrt the Earth, then he will | know that he doesn't know. He won't assume that the train | is stationary on the track. If your argument depends on the passenger being ignorant, and the person on the ground not observing anything, you don't have anything at all. >> > Now you have a passenger who "sees/knows" that the ray which >> > was heading for earth center (or wherever) has had its velocity >> > altered. >> >> If he was ignorant of measurements of the speed of light >> under a variety of conditions, then he would think that. >> If he knew about those observations, he would not. >> Instead, he would know that the speed of light is c. > > This is somewhat sly; experiments which unambiguously test light > speed IN A VACUUM comparing between moving and stationary sources, > have NEVER been done!!! The nearest would be the highly speculative > and assumptive data used to look at emr from binaries, and as the > data was collected and analysed USING c=c+v in the first place, > it is worthless. Particle beams at near-light speed travel in a vacuum. They are often kept circulating in storage rings for hours at a time. They do not bump into the walls of the storage rings because the timing of the magnetic fields takes relativistic effects into account. GPS satellites operate in vacuum. You know that the timing is precise to within a few nanoseconds, and that if relativistc effects (SR and GR) were not taken into account, the timing would be off by microseconds per day. Space probes in deep Space, such as the Hayabusa spacecraft now orbiting asteroid Itokawa, are in vacuum and move at high speeds relative to Earth. Their positions relative to Earth are often very well known from triangulation on other Solar System objects, done by the spacecraft. The communication time lags can often be measured very precisely. No hint that the speed of light is anything other than c. If interpretations of observations of binary stars are based on the assumption that c is constant, and the interpretation is that the stars are orbiting each other in elliptical orbits, rather than some other pattern, then the observations support the assumption. That's enough for now. I'll probably continue this later. -- Jeff, in Minneapolis
From: Henri Wilson on 15 Sep 2005 20:02 On Wed, 14 Sep 2005 23:02:26 +0100, "George Dishman" <george(a)briar.demon.co.uk> wrote: I left out the '1'. see www.users.bigpond.com/hewn/group1.jpg Sagnac says nothing about how light travels across empty space. HW. www.users.bigpond.com/hewn/index.htm Sometimes I feel like a complete failure. The most useful thing I have ever done is prove Einstein wrong.
From: Eric Gisse on 15 Sep 2005 21:30 Henri Wilson wrote: [snip] When are you going to reproduce the two seperate derivations that both George and myself have asked you for? If you actually had a degree in applied math, as you have stated in the past, it shouldn't be too difficult for you to reproduce something you already did.
From: Paul B. Andersen on 16 Sep 2005 08:06
Henri Wilson wrote: > On Tue, 13 Sep 2005 12:34:46 +0200, "Paul B. Andersen" > <paul.b.andersen(a)deletethishia.no> wrote: > > >>Henri Wilson wrote: >> >>>Use a four mirror system. >> >>Paul B. Andersen wrote January 2005: >>| Done. >>| In less than one hour. >>| To a first order approximation, (that is, ignoring >>| terms containing higher than first order of >>| the tangential mirror speed v) the light will use >>| the same time in both directions. >>| The math isn't very hard, but it isn't trivial either. >>| I won't bother to go through all the math in this awkward >>| medium, but I will write the first order terms: >>| The length of one chord of the light path will be: >>| d = srt(2)*r + v*t/sqrt(2) >>| where r is the radius of the circle tangenting the mirrors, >>| and t is the time the light uses to traverse the chord. >>| The speed of the light will be: >>| c' = c + v/sqrt(2) >>| Note that these equations are valid for both direction, >>| v being negative for the beam going in the opposite direction. >>| So we have: >>| c'*t = d >>| c*t + v*t/sqrt(2) = sqrt(2)*r + v*t/sqrt(2) >>| t = sqrt(2)*r/c >>| The ballistic theory predicts that the time >>| has no first order dependency on the speed! >>| >>| The sagnac effect IS a first order effect! >>| >>| You are proven wrong. >> >>Henri Wilson responded: >>| I did that calculation a long time ago. >> >> >>So why keep discussing what is settled a long time ago? >>The ballistic theory predicts no Sagnac effect. >>The ballistic theory is falsified. > > > Rubbish. What's rubish? The calculation you did a long time ago showing that the ballistic theory predicts that the time has no first order dependency on the speed? > You know that the sagnac supports LET if anything. Quite. Sagnac confirms LET, Michelson's ether theory and SR. It falsifies the ballistic theory. > It does not rfute the BaT because the light emitted by the source is moving > normal to hte next mirror IN THAT MIRROR'S FRAME. It is NOT moving at c+v wrt > that mirror at all. Well said. That's why Sagnac falsifies BaT. Paul |