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Natural Science Forum / Physics / Relativity / February 2005Question About Starlight.
Can any SRian please give reasons why all starlight should not spend its lifetime traveling through space at c relative to its original source? It has no contact with any other body...so why should that speed change? HW. www.users.bigpond.com/hewn/index.htm > Can any SRian please give reasons why all starlight should not spend its > lifetime traveling through space at c relative to its original source? I have no idea what an SRian might be. Perhaps it is something related to an EVOLian in the eyes of a fanatic creationist. But anyway, stars tend to move with respect to you, so "the rate of change of the distance between the light and the star as calculated or observed by *you*" aka "the closing speed between light and star according to *you*" aka [Dangerous Terminology Warning] "the relative speed between light and star as seen by *you*" can have any value between 0 and (not including) 2c. As seen from the star, the light always has speed c, since, like you can guess, the star has speed 0 with respect to itself. > It has no contact with any other body...so why should > that speed change? I hope you are intelligent enough to answer this yourself. Dirk Vdm >> Can any SRian please give reasons why all starlight should not spend its >> lifetime traveling through space at c relative to its original source? [quoted text clipped - 11 lines] > "the relative speed between light and star as seen by *you*" >can have any value between 0 and (not including) 2c. I'm sorry but I cannot see how you or I enter into this problem. >As seen from the star, the light always has speed c, >since, like you can guess, the star has speed 0 with [quoted text clipped - 4 lines] > >I hope you are intelligent enough to answer this yourself. If you accept that the speed does not change then you accept that light from different parts of a star's orbit will take different times to traverse a fixed distance to a distant body. You are then accepting the ballistic theory of light and the fact that most variable star brightness curves are a direct consequence of it. >Dirk Vdm HW. www.users.bigpond.com/hewn/index.htm > >> Can any SRian please give reasons why all starlight should not spend its > >> lifetime traveling through space at c relative to its original source? [quoted text clipped - 22 lines] > > > >I hope you are intelligent enough to answer this yourself. Yet, I had left a *very* obvious clue with the asterisks around the you-word, but you decided to make a joke of it. Ah well... > If you accept that the speed does not change then you accept > that light from different parts of a star's orbit ... has the same speed by anyone who directly measures it. However, if you (yes, you again, but to avoid frightening you, I won't use the asterisks this time) would calculate the *closing speed* between the light and the different parts of the orbit, you would find different values. But you would *never* observe different values yourself, nor would anyone else who is composing a brightness curve. So I would not even be remotely *interested* in the following: > will take different times to traverse a fixed > distance to a distant body. > You are then accepting the ballistic theory of light and the > fact that most variable star brightness curves are a direct > consequence of it. Obviously not. Now, go back to the upper part of my previous post and try to *understand* with your brain why every word is there and what it precisely means, and again, have an honest go at answering your own question: | "It has no contact with any other body...so why should | that speed change?" Dirk Vdm >> >> Can any SRian please give reasons why all starlight should not spend its >> >> lifetime traveling through space at c relative to its original source? [quoted text clipped - 31 lines] > >... has the same speed by anyone who directly measures it. Nobody is measuring it. >However, if you (yes, you again, but to avoid frightening you, >I won't use the asterisks this time) would calculate the >*closing speed* between the light and the different parts of >the orbit, you would find different values. But you would >*never* observe different values yourself, nor would anyone >else who is composing a brightness curve. .....and you have proof of this????? >So I would not even be remotely *interested* in the following: > [quoted text clipped - 11 lines] > | "It has no contact with any other body...so why should > | that speed change?" You must be plain dumb if you cannot see that light from different parts of a star's orbit will not travel at the same speed through space. . >Dirk Vdm HW. www.users.bigpond.com/hewn/index.htm > >> >> Can any SRian please give reasons why all starlight should not spend its > >> >> lifetime traveling through space at c relative to its original source? [quoted text clipped - 11 lines] > >> > "the relative speed between light and star as seen by *you*" > >> >can have any value between 0 and (not including) 2c. [snip] > >Now, go back to the upper part of my previous post > >and try to *understand* with your brain why every [quoted text clipped - 6 lines] > different parts of a > star's orbit will not travel at the same speed through space. Wilson, you asked two questions. As an answer to the first question, I gave you a little terminology lesson, so you could use that to answer your second question. I am not interested one bit in whatever it is that you happen to give the label "ballistic theory". I have given you the opportunity to show us that you have enough intelligence to answer your *own* second question in the context of the terminology context that I provided as an answer to your first question. Surely you can do *that*? Dirk Vdm >> >> >> Can any SRian please give reasons why all starlight should not spend its >> >> >> lifetime traveling through space at c relative to its original source? [quoted text clipped - 37 lines] > >Dirk Vdm As usual, you show a complete inability to contribute usefully to a scientific discusion. Why do you bother? HW. www.users.bigpond.com/hewn/index.htm > >> >> >> Can any SRian please give reasons why all starlight should not spend its > >> >> >> lifetime traveling through space at c relative to its original source? [quoted text clipped - 41 lines] > to a scientific discusion. > Why do you bother? Scientific discussion? You ask two questions. I give the answer to the first question so you can learn something by honestly trying to answer your second question, while using the information you just requested and received. Since you obviously seem not prepared (or unable) to do that, I ask you: why do you bother asking questions if you are not interested in the answers? Dirk Vdm >> >> >> >> Can any SRian please give reasons why all starlight should not spend its >> >> >> >> lifetime traveling through space at c relative to its original source? [quoted text clipped - 52 lines] > >Dirk Vdm I see you have applied the SRian 'last resort' tactics. When all else fails, accuse your oponent of 'not understanding' relativity. I can assure you it is only those who fully understand it who can see why it is 100% drivel. HW. www.users.bigpond.com/hewn/index.htm > >> >> >> >> Can any SRian please give reasons why all starlight should not spend its > >> >> >> >> lifetime traveling through space at c relative to its original source? [quoted text clipped - 59 lines] > I can assure you it is only those who fully understand it who can see why it is > 100% drivel. Wilson, my second, third, and fourth replies didn't have *anything* to do with relativity. They were entirely about human interaction and your way of practicing it. You asked a technical question, I give a very carefully worded and honest reply and a simple exercise to allow you to convince me that you understood the answer. I really am not trolling or pulling your leg or something Do you want help with the second question? Dirk Vdm > > >> >> >> >> Can any SRian please give reasons why all starlight should not spend its > > >> >> >> >> lifetime traveling through space at c relative to its original source? [quoted text clipped - 70 lines] > > Dirk Vdm Henri, Dirk is probably good enough at mathematics to make some sense of the iso-extinction contour data I posted to you some whiles ago. http://www.ingentaconnect.com/content/klu/astr/2002/00000280/F0020001/00406931 }}} [PDF] METHODS TO ACCOUNT FOR INTERSTELLAR EXTINCTION 1. Introduction File Format: PDF/Adobe Acrobat ... their location on the sky will trace the corresponding absorption contour. ... reddening as discussed in the previous Section, and iso-extinction contours may be }}} After all, isn't that the crux of you beef with de Sitter anyway ? If you kids can play nice for a whole week I promise I'll leave Google-Beta alone and we'll all be better off for it. :-) Sue... > > > >> >> >> >> Can any SRian please give reasons why all starlight should not spend its > > > >> >> >> >> lifetime traveling through space at c relative to its original source? [quoted text clipped - 88 lines] > > Sue... I don't think anyone is interested in your random references to random articles. Dirk Vdm > > > > >> >> >> >> Can any SRian please give reasons why all starlight should not spend its > > > > >> >> >> >> lifetime traveling through space at c relative to its original source? [quoted text clipped - 93 lines] > > Dirk Vdm You don't know whether it is random or not or you would know it is $40 cheaper here: http://www.astro.lt/gaia/proceedings/15/knude1.pdf or here: http://adsabs.harvard.edu/abs/2002Ap&SS.280...97K Sue... >> > I see you have applied the SRian 'last resort' tactics. >> > [quoted text clipped - 29 lines] >If you kids can play nice for a whole week I promise I'll leave Google-Beta alone >and we'll all be better off for it. :-) Extinction is a major factor. I have now also shown that the thermal speeds of source molecules and the source star's own equatorial speed can profoundly affect the shape of any ballistically predicted brightness curve. In particular, the 'bright flashes and double images' that were the main argument behind DeSitter's 'disproof' will not necessarily occur as he expected. >Sue... HW. www.users.bigpond.com/hewn/index.htm > have no idea what an SRian might be. A kind of brandy they drink on Star Trek! =[ d > Can any SRian please give reasons why all starlight should not spend its > lifetime traveling through space at c relative to its original source? In SR/GR, the light ray at each point along its trajectory simply travels along the path that is a smooth continuation of the path it was on an instant before; this is known as a null geodesic. In particular, at each point only local information is involved in determining the light ray's path. This is obviously completely unrelated to it source, once it is ~0.001 mm away from its source. > It has no contact with any other body...so why should that speed change? It has no "contact" with its source, either. So why should the source influence or determine its propagation far away? (0.001 mm is "far away" here, as is a billion lightyears....) For instance, imagine the light ray enters an optical medium, and suddenly moves with speed c/n -- how does its source affect or determine this? Ditto for when it leaves and resumes speed c.... All physics is local. All modern fundamental theories of physics obey that dictum. And it seems rather unlikely that any sensible theory could violate it (hmmm -- at least for distances much larger than the Planck scale). Tom Roberts tjroberts@lucent.com >> Can any SRian please give reasons why all starlight should not spend its >> lifetime traveling through space at c relative to its original source? [quoted text clipped - 3 lines] >this is known as a null geodesic. In particular, at each point only local >information is involved in determining the light ray's path. Tom, my question related to travel in completely empty space. There are no 'points', local or otherwise in such. >This is obviously completely unrelated to it source, once it is ~0.001 mm away >from its source. Tom, do you agree that light cannot traverse a 'length of space' in zero time? The question is, "what determines the time it DOES take?" We can specify a length in space, using a rod...... and rod lengths are constant no matter how they are moved. >> It has no contact with any other body...so why should that speed change? > >It has no "contact" with its source, either. So why should the source influence >or determine its propagation far away? (0.001 mm is "far away" here, as is a >billion lightyears....) Are you claiming that light DOES NOT move at c wrt its source? In completely empty space, does light have any speed determining reference other than its source? > For instance, imagine the light ray enters an optical medium, and > suddenly moves with speed c/n -- how does its source affect or > determine this? Ditto for when it leaves and resumes speed c.... Obviously the speed of the medium wrt the source also influences the light's speed IN THE MEDIUM, ""wrt the source"". However the question referred to light's travel through completely empty space, until it reaches a target. Since it encounters nothing that might alter its 'speed' (wrt its source) why should that speed not always remain at c wrt the (original) source. And that being obviously true, how can light from differently moving sources take the same time to traverse the same length of empty space? v<-S1__________________________O v->S2 Sources S1 and S2 emit a light pulse towards O as they pass. It is clearly impossible for both pulses to reach O at the same instant since the pulses are clearly both moving at c wrt their individual sources. To support YOUR view, you must revert to aether theory....ie, a property of space alone determines light's speed between any two 'points'. >All physics is local. All modern fundamental theories of physics obey that >dictum. And it seems rather unlikely that any sensible theory could violate it >(hmmm -- at least for distances much larger than the Planck scale). Well we need not refer to what happens to light as it travels through billion of LYs of empty space as 'physics'. Let's call it cosmology. Physics clearly cannot handle such an important question as "what is light doing when it is not being observed?". >Tom Roberts tjroberts@lucent.com HW. www.users.bigpond.com/hewn/index.htm >>>Can any SRian please give reasons why all starlight should not spend its >>>lifetime traveling through space at c relative to its original source? [quoted text clipped - 5 lines] > > Tom, my question related to travel in completely empty space. As was my answer. > There are no 'points', local or otherwise in such. In my discussion, a point is merely a location along the light ray's path. >>This is obviously completely unrelated to it source, once it is ~0.001 mm away >>from its source. > > Tom, do you agree that light cannot traverse a 'length of space' in zero time? Yes, as long as one specifies in what frame the "time" is measured. > The question is, "what determines the time it DOES take?" The relationship between the frame in which the time is measured and the local lightcone structure of the spacetime through which the light is traveling. > We can specify a length in space, using a rod...... and rod lengths are > constant no matter how they are moved. Sure. The same is true for clock intervals. Using some inertial frame: locate two clocks at the ends of your rod, synchronize those clocks, and then rod and clocks can be used to measure the speed of light that travels along the rod. So what? >>>It has no contact with any other body...so why should that speed change? >>It has no "contact" with its source, either. So why should the source influence >>or determine its propagation far away? (0.001 mm is "far away" here, as is a >>billion lightyears....) > > Are you claiming that light DOES NOT move at c wrt its source? In GR, yes; in SR, no. But one must be more precise (it is the inertial frame of the source that matters, not the source itself). In both SR and GR, at each point along its path, light travels with speed c relative to any LOCALLY-INERTIAL frame. This need have no relationship whatsoever to its source. Note, however, in SR any inertial frame can be extended to cover the entire manifold, so the locally-inertial frame of the source can be extended to any point along the light ray's path, so in SR the light ray travels with speed c relative to the inertial frame of its source everywhere along its path. Ditto for any other locally-inertial frame in SR. This does not hold in GR, as such an extension of a locally- inertial frame is in general not possible. > In completely empty space, does light have any speed determining reference > other than its source? Yes. The local lightcone structure of spacetime. That is _ALL_ that matters for the speed of light in SR/GR. > [...] Tom Roberts tjroberts@lucent.com >>>>Can any SRian please give reasons why all starlight should not spend its >>>>lifetime traveling through space at c relative to its original source? [quoted text clipped - 18 lines] > >Yes, as long as one specifies in what frame the "time" is measured. Oh? Do you know of a frame in which light takes ZERO time to traverse a set distance? >> The question is, "what determines the time it DOES take?" > >The relationship between the frame in which the time is measured and the local >lightcone structure of the spacetime through which the light is traveling. Is that a lightcone based on constant c? You are assuming the second postulate its true. >> We can specify a length in space, using a rod...... and rod lengths are >> constant no matter how they are moved. [quoted text clipped - 3 lines] >clocks can be used to measure the speed of light that travels along the rod. So >what? So, TOM, if the light souce IS NOT at rest wrt the rod, what will the answer be? >>>>It has no contact with any other body...so why should that speed change? >>>It has no "contact" with its source, either. So why should the source influence [quoted text clipped - 12 lines] >relative to the inertial frame of its source everywhere along its path. Ditto >for any other locally-inertial frame in SR. That's the second postulate, yes. But it doesn't answer my question. > This does not hold in GR, as such an extension of a locally- > inertial frame is in general not possible. [quoted text clipped - 4 lines] >Yes. The local lightcone structure of spacetime. That is _ALL_ that matters for >the speed of light in SR/GR. No I don't think you are answering my question Tom. Let me rephrase it again. v<-S1__________________________> v->S2 Relatively moving sources, S1 and S2 simultaneously emit a light pulse in a particular direction as they pass. According to SR, those pulses remain adjacent as they move through space. What is the physical process that causes this to happen? > > [...] > >Tom Roberts tjroberts@lucent.com HW. www.users.bigpond.com/hewn/index.htm [snip] > What is the physical process that causes this to happen? Why do you ask when you know nobody will give you an answer that satisfies you? [snip] > [snip] > > > What is the physical process that causes this to happen? > > Why do you ask when you know nobody will give you an > answer that satisfies you? Perhaps he asks questions with the only purpose of starting another discussion. That is what I experienced on this thread. I think he very clearly showed that his intentions are those of a troll. He could just as well go to a biology newsgroup and ask a technical question about selective environmental pressure, getting a technical answer, and then tell the person who was kind enough to help, that his "arguments" are those of a creationist like himself. He has been doing exactly this for years on this newsgroup. I had decided to give him another chance, but apparently he really can't help it. I think he sees himself as a smart and devious little man, but alas, he is so transparent that it's almost tragical :-) Dirk Vdm >> [snip] >> [quoted text clipped - 18 lines] > >Dirk Vdm This experiment shows that SR is dead. <-vS1__________________________>p1,p2 ->vS2 Two relatively moving sources emit a pulse of light as they pass. According to SR, the two pulses will travel through empty space together. Please explain how and why this should happen. Note: there are NO observers involved here. Also note: SR claims that the pulses travel together because it says that if an observer anywhere DOES suddenly get in their way, they will strike him simultaneously. So either SR must assume that properties of space cause the pulses to acquire a common speed or it claims that at least one of the pulses does NOT travel at c wrt its source. Particularly note: If the light sources are replaced by loud speakers moving through air and they emit a 'beep' as they pass, the two beeps WILL travel through air together. So SR assumes light in space is analogous to sound in air. SR is clearly just an alternative aether based theory. HW. www.users.bigpond.com/hewn/index.htm Sometimes I feel like a complete failure. The only useful thing I have ever done is prove Einstein wrong. > >> [snip] > >> [quoted text clipped - 20 lines] > > This experiment shows that SR is dead. Interesting, funny and entertaining, but identical to the new thread you just started, so take your bags and move. Dirk Vdm (cut) > Two relatively moving sources emit a pulse of light as they pass. > [quoted text clipped - 3 lines] > > Note: there are NO observers involved here. Nobody knows why the speed of light is the only speed there is, any more than there is an explanation for why electrons have the specific charge they do- it's a given law of nature. We DO know that light does not travel at speed c solely with respect to the SOURCE. There are plenty of multiple star systems in our galaxy, many with orbital planes close to our line of sight. Considering the large distances, measured in light years or light centuries, in some of these cases the earlier light from a star travelling AWAY from us in its orbit, travelling at c-v, would have time to be passed up by light travelling at c+v later in the orbit. We would have cases of multiple images of the same star at different parts of the orbit. We NEVER see such an occurrence in our galaxy, therefore we know that light travels at speed c and not c+v . Of course we have a few multiple images of GALAXIES, not stars, but these are due to General Relativistic bending of starlight.- A. McIntire (cut) >> >"Eric Gisse" <jowr.pi@gmail.com> wrote in message >news:1109505831.718057.46540@f14g2000cwb.googlegroups.com... [quoted text clipped - 24 lines] >not stars, but these are due to General Relativistic bending of >starlight.- A. McIntire You are obviously new here and unaware of the intense discussion currently being undertaken with regard to variable stars and the resons why DeSitter was wrong. The ballistic theory stands up to all criticism. >(cut) HW. www.users.bigpond.com/hewn/index.htm Sometimes I feel like a complete failure. The only useful thing I have ever done is prove Einstein wrong. [snip] > The ballistic theory stands up to all criticism. ...that Henri Wilson allows. [snip] |
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