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The evidence for light speed delay extrapolation beyond a second
is confounded by the delays of packing and unpacking bits in the uplink and downlink streams etc.. Also the software for communications between earth and the craft assumes light speed delay extrapolation. How to test it? 1)The Mars Rover could wave in response to a command from the Earth and successive images from the cameras before during and after this command might show it. 2) The Pioneer 10 Doppler Data could show that data was only received when transmission was going on at the same time at the same or other site in view of the craft and that the Doppler shifts were more accurately predicted on this assumption. The data is available at http://bestweb.net/~sansbury/Doppler |
#2
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![]() "ralph sansbury" wrote in message ... The evidence for light speed delay extrapolation beyond a second is confounded by the delays of packing and unpacking bits in the uplink and downlink streams etc.. Also the software for communications between earth and the craft assumes light speed delay extrapolation. How to test it? 1)The Mars Rover could wave in response to a command from the Earth and successive images from the cameras before during and after this command might show it. 2) The Pioneer 10 Doppler Data could show that data was only received when transmission was going on at the same time at the same or other site in view of the craft and that the Doppler shifts were more accurately predicted on this assumption. The data is available at http://bestweb.net/~sansbury/Doppler Previous Discussion with William Owen of NASA( He acknowledges that he does not know the details of how the radio science time processes the data but no one from these teams has entered this discussion): WO Here are some examples:[of evidence that the speed of light delay extrapolates beyond a second] 1)The eclipses of Jupiter's moons.... RS Cassini said that Roemer's delays could have been due to changes in the observability of Jupiter's moons from the earth. WO 2)The light curves of binary stars are shifted in phase according to the earth's position in its orbit and so it is necessary to change the time of observation from what it is on the ground to what it is when the same light wave passes the sun. For example an eclipse of V471 Tauri lasts ten minutes but this recorded as occurring ten minutes before it is actually observed. RS I gather that the time between eclipses is more regular when you do this but that is an imposed regularity and need have no other significance. WO Radar ranging to the planets has a round trip light time as expected... RS If you look at the details you will see that the analysis of the time series of radar noise from the direction of the planet eg Venus is done by starting the time series at various microsecond interval near the expected time of the reflected signal and selecting the time series that most resembles the sent time series and attributing variations to surface irregulaties. This map needless to say has never been confirmed in any detail by later radar data using spacecraft orbiting Venus. WO Laser ranging to retroreflectors left on the moon's surface; RS The return signals are very weak and the few seconds delay of the return signals and atmospheric scattering do not permit a precise confirmation that the delay is greater than two seconds. WO Countinual Ranging Code indicate the speed of light extrapolates. RSYour word "continual" suggests that a ranging signal could be going out during the same time interval as an incoming ranging signal is received as expected and the incoming ranging signal could be due to the just sent outgoing ranging signal. WOI can ask around and find out *exactly* how it is done, but the nuts and bolts of if must work soemthing like this. First, the spacecraft must be told to point its antenna at the earth and keep its "ears"open. These commands to the attitude system and to the radio system are typically included in a "sequence" of commands that are sent to the spacecraft days or weeks in advance. Second the particular DSN antenna must also be configured correctly. Then when the right time comes, the antenna starts transmitting the range code dand it does this continuously for the prescribed time, perhhaps as long as 10 or 12 hours. As the time approaches for the return signal to arrive, either that antenna *or a different one* listens for the incoming signal. The arrival time of the bits is determined, compared to the known transmittal time of the same bits, and the difference is the round trip light time" which is in essence the observation that we use in our orbit determination process, And the piece of this that speaks particularly to your objection is that the range code has a beginning and an end. True, the bit pattern repeats after a while, but if the return signal also has a beginning and an end, would that not satisfy you?...the code repeats at least for the Mark 1 ranging system every 2 and 2/3 seconds about. RS But this is not long enough. So there is no way of telling if your are receiving a part of this code that was sent a few seconds before or that was sent hours before. And isnt it the case that the estimation of craft location is based not only on estimates of light speed delay but on previous estimates of position going back to launch and maybe small corrections at that time due to Doppler etc and Newtonian forces mainly the sun and Jupiter on the craft after it has left earth? WOYes |
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![]() "ralph sansbury" wrote in message ... 1)The eclipses of Jupiter's moons.... RS Cassini said that Roemer's delays could have been due to changes in the observability of Jupiter's moons from the earth. Ralph, why not repeat the observations yourself? George |
#4
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![]() "George Dishman" wrote in message ... "ralph sansbury" wrote in message ... 1)The eclipses of Jupiter's moons.... RS Cassini said that Roemer's delays could have been due to changes in the observability of Jupiter's moons from the earth. Ralph, why not repeat the observations yourself? George George, you miss the point. The point is that the observed greater delays in the emergence of a moon from Jupiter's shadow when the earth was further from Jupiter are attributable to the difference in the line of sight between Jupiter and Earth at these different relative orientations. Astronomers since Cassini know this. Now with more and better observations of Jupiter etc it is perhaps not just a possible interpretation but the only interpretation. |
#5
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![]() "ralph sansbury" wrote in message ... "George Dishman" wrote in message ... "ralph sansbury" wrote in message ... 1)The eclipses of Jupiter's moons.... RS Cassini said that Roemer's delays could have been due to changes in the observability of Jupiter's moons from the earth. Ralph, why not repeat the observations yourself? George, you miss the point. The point is that the observed greater delays in the emergence of a moon from Jupiter's shadow when the earth was further from Jupiter are attributable to the difference in the line of sight between Jupiter and Earth at these different relative orientations. Astronomers since Cassini know this. Now with more and better observations of Jupiter etc it is perhaps not just a possible interpretation but the only interpretation. Well isn't that the point? The line-of-sight distance changes and there is a matching delay in the observed time of the transit. The ratio of these gives the speed of light. If there was a problem with observability, which I take to mean some events were not observable for example due to cloud cover, it has long since been eliminated. George |
#6
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![]() "George Dishman" wrote in message ... "ralph sansbury" wrote in message ... "George Dishman" wrote in message ... "ralph sansbury" wrote in message ... 1)The eclipses of Jupiter's moons.... RS Cassini said that Roemer's delays could have been due to changes in the observability of Jupiter's moons from the earth. Ralph, why not repeat the observations yourself? George, you miss the point. The point is that the observed greater delays in the emergence of a moon from Jupiter's shadow when the earth was further from Jupiter are attributable to the difference in the line of sight between Jupiter and Earth at these different relative orientations. Astronomers since Cassini know this. Now with more and better observations of Jupiter etc it is perhaps not just a possible interpretation but the only interpretation. Well isn't that the point? The line-of-sight distance changes and there is a matching delay in the observed time of the transit. There need be no delay at all. Look out the window at a car driving by. If you are at various distances from the window and at different positions in the room the car will come into view and disappear from view at different times. Nothing to do with the speed of light. The ratio of these gives the speed of light. If there was a problem with observability, which I take to mean some events were not observable for example due to cloud cover, it has long since been eliminated. George |
#7
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ralph sansbury wrote:
"ralph sansbury" wrote in message ... The evidence for light speed delay extrapolation beyond a second is confounded by the delays of packing and unpacking bits in the uplink and downlink streams etc.. Also the software for communications between earth and the craft assumes light speed delay extrapolation. How to test it? 1)The Mars Rover could wave in response to a command from the Earth and successive images from the cameras before during and after this command might show it. 2) The Pioneer 10 Doppler Data could show that data was only received when transmission was going on at the same time at the same or other site in view of the craft and that the Doppler shifts were more accurately predicted on this assumption. The data is available at http://bestweb.net/~sansbury/Doppler Previous Discussion with William Owen of NASA( He acknowledges that he does not know the details of how the radio science time processes the data but no one from these teams has entered this discussion): WO Here are some examples:[of evidence that the speed of light delay extrapolates beyond a second] 1)The eclipses of Jupiter's moons.... RS Cassini said that Roemer's delays could have been due to changes in the observability of Jupiter's moons from the earth. WO 2)The light curves of binary stars are shifted in phase according to the earth's position in its orbit and so it is necessary to change the time of observation from what it is on the ground to what it is when the same light wave passes the sun. For example an eclipse of V471 Tauri lasts ten minutes but this recorded as occurring ten minutes before it is actually observed. RS I gather that the time between eclipses is more regular when you do this but that is an imposed regularity and need have no other significance. I'll just comment on this one since BD +16d516 (V471 Tau) has long been one of my favorite objects. Actually, Bill Owen was slightly off as V471 has eclipses about every 12.5 hours and the ingress to eclipse takes about 60 seconds (the duration is about 60 minutes ... quick question I ask my students (I probably asked Bill years ago) .... what is the approximate ratio of radii of the stars involved). I nearly missed my first observation of a V471 eclipse (many years ago) because I had neglected to include the light-time correction in my planning and was about to take one more observation of the comparison star when I saw the strip chart recorder dropping rapidly in U. If light-time is taken into effect, the eclipses of V471 are easily predicted to an accuracy of a second in time, without it one has to assume that the time of eclipses is exactly modulated by a function that mimics the earth's orbital motion. The same is true of all eclipsing systems but few have such a sharply defined eclipse as V471. -- John Oliver Associate Professor Associate Chair/Undergraduate Coordinator Department of Astronomy University of Florida Project AST@RHO http://astrho.astro.ufl.edu see the night sky at http://concam.net/rh/ |
#8
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![]() "John Oliver" wrote in message news:UobTb.1809$Yj.1735@lakeread02... ralph sansbury wrote: "ralph sansbury" wrote in message ... The evidence for light speed delay extrapolation beyond a second is confounded by the delays of packing and unpacking bits in the uplink and downlink streams etc.. Also the software for communications between earth and the craft assumes light speed delay extrapolation. How to test it? 1)The Mars Rover could wave in response to a command from the Earth and successive images from the cameras before during and after this command might show it. 2) The Pioneer 10 Doppler Data could show that data was only received when transmission was going on at the same time at the same or other site in view of the craft and that the Doppler shifts were more accurately predicted on this assumption. The data is available at http://bestweb.net/~sansbury/Doppler Previous Discussion with William Owen of NASA( He acknowledges that he does not know the details of how the radio science time processes the data but no one from these teams has entered this discussion): WO Here are some examples:[of evidence that the speed of light delay extrapolates beyond a second] 1)The eclipses of Jupiter's moons.... RS Cassini said that Roemer's delays could have been due to changes in the observability of Jupiter's moons from the earth. WO 2)The light curves of binary stars are shifted in phase according to the earth's position in its orbit and so it is necessary to change the time of observation from what it is on the ground to what it is when the same light wave passes the sun. For example an eclipse of V471 Tauri lasts ten minutes but this recorded as occurring ten minutes before it is actually observed. RS I gather that the time between eclipses is more regular when you do this but that is an imposed regularity and need have no other significance. I'll just comment on this one since BD +16d516 (V471 Tau) has long been one of my favorite objects. Actually, Bill Owen was slightly off as V471 has eclipses about every 12.5 hours and the ingress to eclipse takes about 60 seconds (the duration is about 60 minutes ... quick question I ask my students (I probably asked Bill years ago) ... what is the approximate ratio of radii of the stars involved). I nearly missed my first observation of a V471 eclipse (many years ago) because I had neglected to include the light-time correction in my planning and was about to take one more observation of the comparison star when I saw the strip chart recorder dropping rapidly in U. If light-time is taken into effect, the eclipses of V471 are easily predicted to an accuracy of a second in time, without it one has to assume that the time of eclipses is exactly modulated by a function that mimics the earth's orbital motion. The same is true of all eclipsing systems but few have such a sharply defined eclipse as V471. Could you expand on this and the possibility that this is not due to the speed of light delay. -- John Oliver Associate Professor Associate Chair/Undergraduate Coordinator Department of Astronomy University of Florida Project AST@RHO http://astrho.astro.ufl.edu see the night sky at http://concam.net/rh/ |
#9
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![]() "ralph sansbury" wrote in message ... "John Oliver" wrote in message news:UobTb.1809$Yj.1735@lakeread02... ralph sansbury wrote: "ralph sansbury" wrote in message ... The evidence for light speed delay extrapolation beyond a second is confounded by the delays of packing and unpacking bits in the uplink and downlink streams etc.. Also the software for communications between earth and the craft assumes light speed delay extrapolation. How to test it? 1)The Mars Rover could wave in response to a command from the Earth and successive images from the cameras before during and after this command might show it. 2) The Pioneer 10 Doppler Data could show that data was only received when transmission was going on at the same time at the same or other site in view of the craft and that the Doppler shifts were more accurately predicted on this assumption. The data is available at http://bestweb.net/~sansbury/Doppler Previous Discussion with William Owen of NASA( He acknowledges that he does not know the details of how the radio science time processes the data but no one from these teams has entered this discussion): WO Here are some examples:[of evidence that the speed of light delay extrapolates beyond a second] 1)The eclipses of Jupiter's moons.... RS Cassini said that Roemer's delays could have been due to changes in the observability of Jupiter's moons from the earth. WO 2)The light curves of binary stars are shifted in phase according to the earth's position in its orbit and so it is necessary to change the time of observation from what it is on the ground to what it is when the same light wave passes the sun. For example an eclipse of V471 Tauri lasts ten minutes but this recorded as occurring ten minutes before it is actually observed. RS I gather that the time between eclipses is more regular when you do this but that is an imposed regularity and need have no other significance. I'll just comment on this one since BD +16d516 (V471 Tau) has long been one of my favorite objects. Actually, Bill Owen was slightly off as V471 has eclipses about every 12.5 hours and the ingress to eclipse takes about 60 seconds (the duration is about 60 minutes ... quick question I ask my students (I probably asked Bill years ago) ... what is the approximate ratio of radii of the stars involved). I nearly missed my first observation of a V471 eclipse (many years ago) because I had neglected to include the light-time correction in my planning and was about to take one more observation of the comparison star when I saw the strip chart recorder dropping rapidly in U. If light-time is taken into effect, the eclipses of V471 are easily predicted to an accuracy of a second in time, without it one has to assume that the time of eclipses is exactly modulated by a function that mimics the earth's orbital motion. The same is true of all eclipsing systems but few have such a sharply defined eclipse as V471. Could you expand on this and the possibility that this is not due to the speed of light delay. In the case of Bradley's observations of stars in the tail of the great bear as instances of stellar aberration, the roughly 30second of arc change in position of the stars when viewed six months apart could be regarded as due to a 3nanosecond delay before their light registered on the rods of the retina of the viewer. So as the earth moved 1meter at the rate of 67000miles/hr in one direction and then six months later in the opposite direction while the polar star was being observed, it would appear to be coming from slightly different positions on the heavenly sphere. This was interpreted as the speed of light relative to the speed of the earth but could equally well be interpreted as the response time to the source of light. Maybe something similar is going on here with respect to the time before the changes in light strength register on the rods of the antenna of the observers eye or on the photoelectric surface aimed at the light source. |
#10
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![]() "ralph sansbury" writes: [ Oliver writes: ] in U. If light-time is taken into effect, the eclipses of V471 are easily predicted to an accuracy of a second in time, without it one has to assume that the time of eclipses is exactly modulated by a function that mimics the earth's orbital motion. The same is true of all eclipsing systems but few have such a sharply defined eclipse as V471. Could you expand on this and the possibility that this is not due to the speed of light delay. There are lots of binary systems where precision timing can be performed. These include eclipsing systems and binary pulsars. In the case of binary pulsars, the timing residuals can be as small as ~35 NANOseconds ( = 10 meters of light travel ). Without correction for light travel time effects, all binaries show a 365.25 day periodic variations in their times of detection of pulsations or eclipses. So the question is: could it really be that all the binaries in the solar system have a planet with 365.25 day period? And furthermore, that the inclinations of those planets are somehow exactly aligned with the plane of the ecliptic? (because light travel time effects scale as cos(ecliptic_latitude)) And further yet, could it really be that radar ranging time to spacecraft, Venus and other asteroids, always scale as the distance between the earth and the target, is just a coincidence? And still further, do we really believe that pulsars' pulsations, and the unique stochastic variations of distant AGN used for VLBI studies, both have time delays which vary *exactly* according to the motion of the observatory(ies) around the earth's center? The answer is of course, NO, to all of these questions. It is not a coincidence that all of these phenomena are observed. One cannot simply explain away each and every binary star system, every spacecraft, every planet, every VLBI observation as coincidental source variations, because then that makes a bigger problem of thousands of unexplained coincidences. There is one simple explanation for all of these phenomena: finite light travel time. CM |
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