Exactly why the theories of relativity are complete nonsense - the basic mistake exposed!
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From: artful on 24 Feb 2010 21:24 On Feb 25, 1:01 pm, Arindam Banerjee <adda1...(a)bigpond.com> wrote: > On Feb 23, 5:21 am, spudnik <Space...(a)hotmail.com> wrote: > > > so, what is the *same* about the waves & the particles? > > They both have velocity that changes with the speed of the emitter > with respect to any reference. Except if we're talking about light, which experiment has found always has the same speed regardless of the speed of the emitter (ie ballistic / emission theories are ruled out experimentally). And except where we're talking about sound, where the speed of the sound has nothing to do with the speed of the emitter.. only the speed of the air and the observer (listener).
From: spudnik on 24 Feb 2010 22:49 I vote for putting sonar & radar on the trainlaunched rocket; what will it cost, and how superpredictable are the results? thus: it's just a matter of time before a big one, or "one's turn" for it; responsible forecasts use big percentages (from the USGS e.g. .-) I have to get on the local Rep's case about cap&trade, although it would certainly slow down any such tectonic fall-out of carbon dioxide. (we just need a small tax on carbon, I guess.) --les OEuvres! http://wlym.com --Stop Cheeny, Rice and the ICC's third British invasion of Sudan! http://larouchepub.com
From: spudnik on 24 Feb 2010 22:50 son, do you know what *commentarium ad hominem* is? > Gosh, people here don't know the fundamentals about science!- Hide quoted text - thus: I vote for putting sonar & radar on the trainlaunched rocket; what will it cost, and how superpredictable are the results? thus: it's just a matter of time before a big one, or "one's turn" for it; responsible forecasts use big percentages (from the USGS e.g. .-) I have to get on the local Rep's case about cap&trade, although it would certainly slow down any such tectonic fall-out of carbon dioxide. (we just need a small tax on carbon, I guess.) --les OEuvres! http://wlym.com --Stop Cheeny, Rice and the ICC's third British invasion of Sudan! http://larouchepub.com
From: Zinnic on 25 Feb 2010 08:51 On Feb 24, 3:10 pm, PD <thedraperfam...(a)gmail.com> wrote: > On Feb 24, 2:37 pm, Zinnic <zeenr...(a)gate.net> wrote: > > > > > > > On Feb 24, 10:50 am, PD <thedraperfam...(a)gmail.com> wrote: > > > > On Feb 24, 9:55 am, Zinnic <zeenr...(a)gate.net> wrote: > > > > > On Feb 24, 8:56 am, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > On Feb 23, 6:19 am, Arindam Banerjee <adda1...(a)bigpond.com> wrote: > > > > > > > On Feb 23, 1:11 pm, Zinnic <zeenr...(a)gate.net> wrote: > > > > > > > > On Feb 21, 11:24 am, Marshall <marshall.spi...(a)gmail.com> wrote: > > > > > > > > > On Feb 21, 4:02 am, Arindam Banerjee <adda1...(a)bigpond.com> wrote: > > > > > > > > > > On Feb 20, 5:20 am, Zinnic <zeenr...(a)gate.net> wrote: > > > > > > > > > > > Arindam claims that the propagation of light and sound are analogous > > > > > > > > > > to propagation of projectiles from a moving platform. My point is that > > > > > > > > > > it is demonstrable that the projectile analogy does NOT hold for > > > > > > > > > > sound. > > > > > > > > > > So why not set up an experiment to prove this one way or the other, > > > > > > > > > This idea interests me. I am clear on how one uses various microphones > > > > > > > > to test arrival time of sound. What is less clear is a good way of > > > > > > > > having a controlled, in-motion emitter. > > > > > > > > > I have two thoughts: > > > > > > > > > 1) Put a speaker on a small vehicle on a track. This would provide > > > > > > > > linear speed but seems hard to control. > > > > > > > > 2) Put a speaker on the end of an arm that is rotating. Have the > > > > > > > > speaker emit a pulse when the arm is 90 degrees to the angle > > > > > > > > to the mics. This is not a linear path, but maybe it doesn't matter. > > > > > > > > It also has the advantage that you could compare the time > > > > > > > > difference of arrival at the two mics when the speaker emits > > > > > > > > at any point on its circular trajectory. > > > > > > > > > Anyone care to comment. It seems like a fun science project.. > > > > > > > > > Marshall > > > > > > > > I have suggested firing a rocket vertically from a speeding train half > > > > > > > way between two listening/viewing stations . Entirely feasible but IMO > > > > > > > not necessary because I believe the question has already been settled > > > > > > > by sonar technology. However, I am still searching for links. > > > > > > > Zinnic- Hide quoted text - > > > > > > > > - Show quoted text - > > > > > > > What is strange, is that an experiment to prove this most basic point > > > > > > is not any standard one! > > > > > > Anyone who has watched a car race from the stands does this > > > > > experiment. This means that there are hundreds of thousands of > > > > > spectator/experimenters every year. Is this not standard?- Hide quoted text - > > > > > > - Show quoted text - > > > > > This tells us nothing about the intrinsic speed (in air) of the sound > > > > wavefront emitted from approaching and receding sound sources (cars). > > > > No, it does, because the amount of the shift (which is clearly > > > observable -- the pitch is numerically coupled to the frequency) > > > depends on the ratio of the speed of the source and the speed of the > > > signal in air. So if you know the speed of the source (from, say, the > > > speedometer or by timing the car's travel over a length of the track), > > > then you know the speed of the signal in the air. (Of course, you can > > > do the opposite as well. If you know the speed of the signal in the > > > air from another measurement, you can find the speed of the car using > > > the frequency shift.) > > > > > It demonstrates only the different intrinsic frequency/wavelength of > > > > the sound > > > > The *intrinsic* frequency, which is the frequency of the source, is > > > not changing. Only the observed one does. > > > I believe your last statement re frequency from a stationary versus a > > moving sound source is incorrect. > > We will agree that a change in intrinsic frequency accompanied by the > > corresponding inverse change in wavelength does not by definition > > (speed = frequency x wavelength) change the intrinsic speed (in air) > > of the sound wavefront. > > However, my understanding is that movement of the sound source does > > change the actual wavelength of the sound emmitted along with the > > corresponding change in frequency so that there is no change in speed > > of the wave front. > > And again, let's be careful here. If you have a source that is > emitting at 250 Hz, then it is producing a wavefront every 4 ms. That > number does not change when the source is moving relative to the > medium. A new wavefront is still created every 4 ms (250 Hz). However, > at the *receiver* in front of the motion of the source, this frequency > is heard as higher, because the wavefronts are closer together > compared to those from a stationary source. That is, the receiver may > receive those wavefronts every 3 ms apart, even though they are being > produced every 4 ms. The frame of reference is the air medium. Thus, as you say, the wave fronts ot the 'note' generated are closer together (compressed) when the train is moving towards a stationary receiver.That is the net frequency/wavelength will be higher/lower than that of the same 'note' emitted from a stationary train. Conversely, the frequency/wavelength will be lower/higher when the train is moving away. That is, a REAL difference in frequency in air of the emitted 'note 'is responsible for the observed Doppler effect. As you know, only an APPARENT difference in frequency in air is responsible for the Doppler effect when the emitter is stationary and the receiver is moving in air. > > That is, the motion of the source compresses or > > decompresses the air oscillations resulting in an intrinsic change in > > the wavelength/frequency of the resulting sound wave form. > > This does not occur when the emitter is stationary and the receptor is > > in motion. In this case there is no change in the actual (intrinsic) > > wavelength/frequency of the sound emitted but only an apparent > > change because the number of air compression oscillations experienced > > per unit time (frequency of experience) is changed by the motion of > > the receiver. > > > Given this, do you believe that the two different frequencies > > recorded for a sound source approaching (+v ) and receding (-v) > > can be used to calculate whether or not the intrinsic speed of sound > > in air changes when the source passes the receiver? > > If you measure the speed of the sound source independently, yes. That > is, if you timed the source by watching it run through two red lights > a known distance apart, you would know what V is, and then by > measuring the shifted frequencies, you could determine what S is. > But that is my question. How does one determine the speed of sound from the different frequencies recorded (at a stationary site) for the same 'note' generated by approaching and receding emitters? Can you explain the math for doing this? > > That is approaching at S + v , receding at S - v, or no difference. > > Unfortunately, the math required is beyond my capacity :-( > > Zinnic- Hide quoted text -
From: Zinnic on 25 Feb 2010 09:32
On Feb 24, 10:50 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > Zinnic wrote: > > On Feb 24, 8:30 am, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > >> Marshall wrote: > >>> [... measuring the speed of sound from a moving source] > >> Get a pair of microphones, some long cords for them, and a laptop with stereo > >> microphone in. Go set up near a train track, with the microphones separated as > >> far as possible alongside the track. Wait for a passing train. Use either its > >> basic noise, or its horn. > > I fail to see how this set up would allow one to assess more than the > > speed of the train. Explain how your separated microphones can be > > used to assess the speed (in air) of the sound wavefront emitted as > > the train approaches and recedes. > > It should be obvious: Set up in a place such that the train will blow its horn > while approaching both your microphones, as you are recording them. From the > recording you can easily determine the time the horn is first heard by each > microphone. From that time difference and the distance between the microphones > you can compute the speed of the horn's sound in the air. > > You could also do this just from the running noise of the train, > but that would probably require a correlation analysis to > determine the time delay. If you don't know what this means, > ignore it and be sure to use the horn. > > For a 20-foot separation (easily achieved), the time difference will be roughly > 20 milliseconds, which for recording at 44.1 kHz is more than 800 samples.. That > implies an accuracy of perhaps 0.2% or about +-2 ft/sec -- trains move much > faster. You must measure the separation to better than 1/4 inch to achieve that > accuracy. Larger separation would permit better resolution. Try to find fast > trains. You could also do this beside an empty country road with a friend > driving a car and blowing its horn at the right place. Be sure to measure the > wind, temperature, humidity, and barometric pressure. > > Tom Roberts Thanx for your response. I entirely agree that it is essential to measure the time for a short sound blast to travel between two points. For example, from its point of origin to its point of reception. Your set up would allow facile testing of variation (if any) in the amount of time (hence speed) for blasts from moving sources to reach a stationary receiver. I am convinced experimental set ups similar to yours have already been used to establish that the speed of sound thru air is not changed by the speed of the emitter. My contention in this thread is that the real or apparent changes in frequency that explain the (two) Doppler effects are not indicative of changes in the actual speed of sound in air. Regards Zinnic |