Speed of Light: A universal Constant?
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From: bz on 24 Jun 2005 20:51 "Arthur Dent" <jp006t2227(a)blueyonder.co.uk> wrote in news:1119649563.403402.140870(a)g44g2000cwa.googlegroups.com: > > > Randy Poe wrote: >> Arthur Dent wrote: >> > Let there be a source of light moving in an elliptical orbit, the >> > barycentre of which is exactly 100 light years away. >> > On a Sunday, 100 years ago, let the source emit light from position A, >> > D >> > C A -----------------> >> > B >> > >> > and let this light arrive on Earth on Sunday of this coming week. >> >> I'm sure others knowledgable about Cepheid variables will >> be able to critique the details of this model (for >> one thing, it will make very specific predictions >> about the non-sinusoidal variation in intensity which >> I suspect don't match up with the data). > >> But let me look at some more elementary points. >> >> > It has taken exactly 100 years to travel across the intervening >> > distance. >> > On Monday (100 years ago), the star has moved to B and is moving away >> > from the Earth at velocity v. >> > It emits light that is approaching us at c-v, and being slightly >> > slower, it takes 100 years and one day to get here, and arrives on >> > Tuesday of next week instead of Monday, a day late. >> > On Tuesday, 100 years ago, it has moved to C, and there being no >> > component of velocity v to be added to the light, it again takes >> > exactly 100 years and arrives here on Tuesday of next week, on time. >> >> So you are saying that the semimajor axis of this orbit >> is two light days, that light at velocity c takes two >> days longer from C than from A to reach Earth. Also >> that the star has traversed from A to C in two days. > > It takes the Earth a year to orbit the sun,six months from A to C, but > I would never claim the semimajor axis of the Earth's orbit was > anything other than about 8 light minutes. > Yes, it take two days for the star to get from A to C, but it doesn't > take light that long and the semi major axis isn't two light days. > I suspect you are confused. He took the 100 vs 101 days. I almost made the same mistake myself. If I didn't make any errors, the star is traveling at 1% of c, or 6.706e6 mph (2.998e3 km/s). The circumference / perimeter of the orbit is 6.438e8 mi (1.036e9 km). Radus 1.025e8 mi (1.649e8 km) 1.102 AU What masses can be orbit at 1.1 AU in 4 days? Well if one of the stars has the mass of our sun, the other need 7145 times the mass of our sun. Assuming the density of both stars is the same as our sun, the other star is going to be 24 times the diameter of our sun. I am not sure what that translates into in magnitude, but it is going to bright. Y'all check my figures. -- bz please pardon my infinite ignorance, the set-of-things-I-do-not-know is an infinite set. bz+sp(a)ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap
From: Jerry on 24 Jun 2005 21:59 Arthur Dent wrote: > Jerry, I'm going to try (probably with futility) to > explain Henri's viewpoint, and mine. We do understand yours. And I understand yours. You have a philosophical prejudice against facts that are contrary to your intuitions. > The model we employ is that the speed of light is > added to the speed of the source. Contradicted by every peer-reviewed experiment and observational analysis intended to determine whether this may be so for over a century. > Using a simple example, I will now try to show you > variability as it appears in the c+v model. > Let there be a source of light moving in an elliptical > orbit, the barycentre of which is exactly 100 light years > away. On a Sunday, 100 years ago, let the source emit > light from position A, > D > C A -----------------> > B > > and let this light arrive on Earth on Sunday of this > coming week. It has taken exactly 100 years to travel > across the intervening distance. > On Monday (100 years ago), the star has moved to B and > is moving away from the Earth at velocity v. > It emits light that is approaching us at c-v, and being > slightly slower, it takes 100 years and one day to get > here, and arrives on Tuesday of next week instead of > Monday, a day late. On Tuesday, 100 years ago, it has > moved to C, and there being no component of velocity v > to be added to the light, it again takes exactly 100 > years and arrives here on Tuesday of next week, on time. > On Wednesday 100 years ago the star has moved to D, > the light takes 99 years and 364 days to travel the void, > and it arrives on Tuesday of next week, a day early. > Thus we see the light from the star at B, C and D, > Monday, Tuesday and Wednesday 100 years ago on Tuesday > of next week, and the light from A on Sunday. The cycle > then repeats, and the star appears to be varying. We have > no telescopes to resolve the positions A,B,C and D, we > can only measure the red shift we observe. > You assume the speed of light is exactly c according > to Einsteinian relativity and the star is intrinsically > varying, attributing the shift to the surface of the star > expanding and contracting. So does the guy who wrote your > software, and just about every other astronomer in this > world. > > Henri and I assume the speed of light is varying according > to Galilean relativity, attributing the shift to the > motion of the star, treating > it as a constant emitter. > > The cepheid is intrinsically varying, we can see it is, > and it is untuitive to believe our eyes. > BUT... it is equally as intuitive to add velocities, and > when we do we expect to find variation in intensity > as I've shown above, the light from B,C, and D arrives > on Tuesday, and we cannot trust our eyes. > So how can we resolve this difference of opinion without > getting hot under the collar with each party insisting > they are the one that is right? Visiting the star would > do it, but that isn't practical. > We have to resolve it with the data that is available. > > Let me hear your suggestion, and then I'll tell you mine. Unfortunately, your model can fit only the GROSS features of Cepheid light curves. As pointed out by myself and others, BaT utterly fails to explain the fact that Cepheid light curves taken at different wavelengths are different, it predicts Doppler effects that are at odds with what are actually observed, it is incapable of explaining the large random variations in peak-to-peak timing that are observed in high resolution photometric measurements, nor is it capable of explaining variations in peak-to-trough magnitude that occur from cycle to cycle. Bat has no explanation for the Mv = -2.80 Log(P) - 1.43 relationship between period and luminosity, and so on and so forth. Please explain RU Cam in terms of BaT: -------------------------------------------- AAVSO Photoelectric Observations of RU Cam John R. Percy and Yvonne Tang RU Cam is a population II Cepheid which "stopped pulsating" in 1965-66. Actually, it did not stop pulsating completely; the amplitude decreased from over a magnitude to about 0.20, and remained stable at that level from 1967 to 1982, according to the work of Bela Szeidl and his colleagues. The period has fluctuated erratically between 17.4 and 26.6 days, but this may be the result of random, cycle-to-cycle fluctuations. As noted below, the HIPPARCOS satellite found a mean period and amplitude of 22.24 days and 0.20 magmitude, during its 3.5-year mission. http://www.aavso.org/observing/programs/pep/pepnewsletter/may1998/main.shtml Jerry
From: Arthur Dent on 25 Jun 2005 03:31 bz wrote: > "Arthur Dent" <jp006t2227(a)blueyonder.co.uk> wrote in > news:1119649563.403402.140870(a)g44g2000cwa.googlegroups.com: > > > > > > > Randy Poe wrote: > >> Arthur Dent wrote: > >> > Let there be a source of light moving in an elliptical orbit, the > >> > barycentre of which is exactly 100 light years away. > >> > On a Sunday, 100 years ago, let the source emit light from position A, > >> > D > >> > C A -----------------> > >> > B > >> > > >> > and let this light arrive on Earth on Sunday of this coming week. > >> > >> I'm sure others knowledgable about Cepheid variables will > >> be able to critique the details of this model (for > >> one thing, it will make very specific predictions > >> about the non-sinusoidal variation in intensity which > >> I suspect don't match up with the data). > > > >> But let me look at some more elementary points. > >> > >> > It has taken exactly 100 years to travel across the intervening > >> > distance. > >> > On Monday (100 years ago), the star has moved to B and is moving away > >> > from the Earth at velocity v. > >> > It emits light that is approaching us at c-v, and being slightly > >> > slower, it takes 100 years and one day to get here, and arrives on > >> > Tuesday of next week instead of Monday, a day late. > >> > On Tuesday, 100 years ago, it has moved to C, and there being no > >> > component of velocity v to be added to the light, it again takes > >> > exactly 100 years and arrives here on Tuesday of next week, on time. > >> > >> So you are saying that the semimajor axis of this orbit > >> is two light days, that light at velocity c takes two > >> days longer from C than from A to reach Earth. Also > >> that the star has traversed from A to C in two days. > > > > It takes the Earth a year to orbit the sun,six months from A to C, but > > I would never claim the semimajor axis of the Earth's orbit was > > anything other than about 8 light minutes. > > Yes, it take two days for the star to get from A to C, but it doesn't > > take light that long and the semi major axis isn't two light days. > > I suspect you are confused. > > He took the 100 vs 101 days. I almost made the same mistake myself. > > If I didn't make any errors, > the star is traveling at 1% of c, or 6.706e6 mph (2.998e3 km/s). > The circumference / perimeter of the orbit is 6.438e8 mi (1.036e9 km). > Radus 1.025e8 mi (1.649e8 km) 1.102 AU > > What masses can be orbit at 1.1 AU in 4 days? Well if one of the stars has > the mass of our sun, the other need 7145 times the mass of our sun. > > Assuming the density of both stars is the same as our sun, the other star > is going to be 24 times the diameter of our sun. > > I am not sure what that translates into in magnitude, but it is going to > bright. > > Y'all check my figures. > > > > > -- > bz > > please pardon my infinite ignorance, the set-of-things-I-do-not-know is an > infinite set. > > bz+sp(a)ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap Egads, try to explain a simple principle and the confusion is rife. Sarcasm mode: What 100 days would that be, I wonder... Did I mention 101 days somewhere? I don't think so. Let me see I can get anyone to understand without getting them confused. "Let there be a source of light moving in an elliptical orbit, the barycentre of which is exactly 100 light years away." Is there 100 days or 101 days mentioned in that? No, I didn't think so. There is 36525 days mentioned, because there are 365.25 days in a year, if y'all want to drawl my figures. "On a Sunday, 100 years ago, let the source emit light from position A, D C A -----------------> B and let this light arrive on Earth on Sunday of this coming week." So the light left the star in June of 1905, on a Sunday, and travelled 36,525 light-days (that is a unit of distance, and rounded) at 300,000 km/second (that is a speed, also rounded) and gets here next Sunday. Drawn to scale, the Earth is off to the right of the screen (in the direction of the arrow) a little way. Not in the next room, not in the next city, but on the next continent. I don't know what it is in meters, nor am I going to work it out, but its a helluva lot. 36,525 days * 60 seconds * 60 minutes * 24 hours * 300,000 kilometers. I'll call this distance d, then y'all won't have to check my figures. "On Monday (100 years ago), the star has moved to B and is moving away from the Earth at velocity v. It emits light that is approaching us at c-v, and being slightly slower, it takes 100 years and one day to get here, and arrives on Tuesday of next week instead of Monday, a day late." That's emission on a Monday in June of 1905. The star had some velocity away from us. It also has a tiny bit of distance further away from us but that gets lost in rounding up, the change in distance is extremely UNimportant. What IS important is the change in speed. The light emitted takes a day longer to reach us. That's 36526 days instead of 36525 days. That's because that big number, d, that I didn't work out, divided by the speed, c-v, as in t = d/(c-v) is slightly more than 36525 = d/c. If you want to work out the value of v, 36525 days = d/c and 36526 days = d/(c-v) You now have two simultaneous equations. Subtracting one from the other, 1 day = d/(c-v) - d/c. I'm not sure if anyone here can manage it except Henri, or even care, it is quite trivial and within the capabilities of a gifted 12-year-old, although beyond the reach of Randy. v is quite small when compared to c and the distance from A to B (which takes light in the order of 100 seconds and the star a day), is quite small, certainly not anything like 1 AU, when compared to d, which is quite large and takes light 100 years. If you really want to quantify the situation instead of simply looking at it qualitatively, it might be advisable to understand it first. Would you care to examine your figures again, because I think you almost made a mistake in thinking 101 days has anything to do with the problem? End sarcasm mode. Arthur Dent.
From: Arthur Dent on 25 Jun 2005 04:52 Jerry wrote: > Arthur Dent wrote: > > Jerry, I'm going to try (probably with futility) to > > explain Henri's viewpoint, and mine. We do understand yours. > > And I understand yours. You have a philosophical prejudice > against facts that are contrary to your intuitions. I could level the same accusation against you. What you call "facts" are phenomena that you interpret according to your beliefs, and not empirical data which is subject to the mind of the observer. However, calling the other litigant in a dispute "prejudiced" serves no purpose, even if he is. > > > The model we employ is that the speed of light is > > added to the speed of the source. > > Contradicted by every peer-reviewed experiment and > observational analysis intended to determine whether > this may be so for over a century. If you are going to use "peer reviewed for over a century" as argument, Ptolemy's view of the geocentric universe was peer reviewed for over 1400 years, you are outdone. The empirical data hasn't changed, only our view of it. Ptolemy's peers had a philosophical prejudice against facts that are contrary to their intuitions. Unfortunately your argument is prejudicial, irrelevant, and carries no weight. > > Using a simple example, I will now try to show you > > variability as it appears in the c+v model. > > Let there be a source of light moving in an elliptical > > orbit, the barycentre of which is exactly 100 light years > > away. On a Sunday, 100 years ago, let the source emit > > light from position A, > > D > > C A -----------------> > > B > > > > and let this light arrive on Earth on Sunday of this > > coming week. It has taken exactly 100 years to travel > > across the intervening distance. > > On Monday (100 years ago), the star has moved to B and > > is moving away from the Earth at velocity v. > > It emits light that is approaching us at c-v, and being > > slightly slower, it takes 100 years and one day to get > > here, and arrives on Tuesday of next week instead of > > Monday, a day late. On Tuesday, 100 years ago, it has > > moved to C, and there being no component of velocity v > > to be added to the light, it again takes exactly 100 > > years and arrives here on Tuesday of next week, on time. > > On Wednesday 100 years ago the star has moved to D, > > the light takes 99 years and 364 days to travel the void, > > and it arrives on Tuesday of next week, a day early. > > Thus we see the light from the star at B, C and D, > > Monday, Tuesday and Wednesday 100 years ago on Tuesday > > of next week, and the light from A on Sunday. The cycle > > then repeats, and the star appears to be varying. We have > > no telescopes to resolve the positions A,B,C and D, we > > can only measure the red shift we observe. > > You assume the speed of light is exactly c according > > to Einsteinian relativity and the star is intrinsically > > varying, attributing the shift to the surface of the star > > expanding and contracting. So does the guy who wrote your > > software, and just about every other astronomer in this > > world. > > > > Henri and I assume the speed of light is varying according > > to Galilean relativity, attributing the shift to the > > motion of the star, treating > > it as a constant emitter. > > > > The cepheid is intrinsically varying, we can see it is, > > and it is untuitive to believe our eyes. > > BUT... it is equally as intuitive to add velocities, and > > when we do we expect to find variation in intensity > > as I've shown above, the light from B,C, and D arrives > > on Tuesday, and we cannot trust our eyes. > > So how can we resolve this difference of opinion without > > getting hot under the collar with each party insisting > > they are the one that is right? Visiting the star would > > do it, but that isn't practical. > > We have to resolve it with the data that is available. > > > > Let me hear your suggestion, and then I'll tell you mine. > > Unfortunately, your model can fit only the GROSS features > of Cepheid light curves. Unfortunately, your model can fit only the GROSS features of eclipsing variable light curves. > As pointed out by myself and > others, BaT utterly fails to explain the fact that Cepheid > light curves taken at different wavelengths are different, > it predicts Doppler effects that are at odds with what are > actually observed, it is incapable of explaining the large > random variations in peak-to-peak timing that are observed > in high resolution photometric measurements, nor is it > capable of explaining variations in peak-to-trough magnitude > that occur from cycle to cycle. I don't know what "Bat" is suppose to stand for, but I'm guessing it is a term Henri coined to describe c+v. Bat has no explanation for > the Mv = -2.80 Log(P) - 1.43 relationship between period > and luminosity, and so on and so forth. Relativity has no explanation for the light curve of Algol. The supposed eclipse is 10 hours in the period of 70 hours, making 52 degrees in the 360 degree orbit. That places an upper limit on the separation of the two bodies, 4.56 stellar radii of the larger, the system is unstable and so on and so forth. Please explain. > > Please explain RU Cam in terms of BaT: > -------------------------------------------- > AAVSO Photoelectric Observations of RU Cam > John R. Percy and Yvonne Tang > RU Cam is a population II Cepheid which "stopped pulsating" > in 1965-66. Actually, it did not stop pulsating completely; > the amplitude decreased from over a magnitude to about 0.20, > and remained stable at that level from 1967 to 1982, > according to the work of Bela Szeidl and his colleagues. > The period has fluctuated erratically between 17.4 and 26.6 > days, but this may be the result of random, cycle-to-cycle > fluctuations. As noted below, the HIPPARCOS satellite found > a mean period and amplitude of 22.24 days and 0.20 magmitude, > during its 3.5-year mission. > http://www.aavso.org/observing/programs/pep/pepnewsletter/may1998/main.shtml > > Jerry That is hardly a proof that c+v is incorrect, Jerry. There could be many explanations, and often we never find the correct one. In the early 1930's Michelson, experimenting at Irvine Ranch, Ca, found different values for the speed of light. No explanation was ever found, and so on and so forth. What I asked you for was a way in which we could resolve our difference of opinion, not a list of data to support your prejudices. Saying the retrograde motion of the outer planets is best explained by them moving in epicycles didn't cut it for Galileo, and pointing to some cepheid that almost stopped varying and claiming "therefore the speed of light is constant", doesn't cut it for me. You've fallen into the age-old trap of saying "I'm right, you are wrong" without resolving the issue. My answer to you must now be "I'm right, you are the one that is wrong", and where does that get us? Here's my suggestion: We (well, you) obtain the following data from the AAVSO: The light curve of Algol with Julian dates clearly provided, accurately observed by multiple astronomers for the date chosen. The velocity curve with the same Julian date clearly provided. >From that, it should be possible to determine whether c constant or c+v is the correct model. Get the data, and I'll tell you how. AD.
From: Jerry on 25 Jun 2005 09:36
Arthur Dent wrote: > Jerry wrote: > > Contradicted by every peer-reviewed experiment and > > observational analysis intended to determine whether > > this may be so for over a century. > > If you are going to use "peer reviewed for over a century" as argument, > Ptolemy's view of the geocentric universe was peer reviewed for over > 1400 years, you are outdone. No, it was worshiped. Different thing. > The empirical data hasn't changed, only > our view of it. Ptolemy's peers had a philosophical prejudice against > facts that are contrary to their intuitions. Unfortunately your > argument is prejudicial, irrelevant, and carries no weight. <snip> > Unfortunately, your model can fit only the GROSS features of eclipsing > variable light curves. You obviously aren't familiar with current programs for modeling eclipsing binaries, which include limb darkening, tidal distortions, etc. Stop being ignorantly facetious. > > As pointed out by myself and > > others, BaT utterly fails to explain the fact that Cepheid > > light curves taken at different wavelengths are different, > > it predicts Doppler effects that are at odds with what are > > actually observed, it is incapable of explaining the large > > random variations in peak-to-peak timing that are observed > > in high resolution photometric measurements, nor is it > > capable of explaining variations in peak-to-trough magnitude > > that occur from cycle to cycle. > > I don't know what "Bat" is suppose to stand for, but I'm guessing it is > a term Henri coined to describe c+v. > > Bat has no explanation for > > the Mv = -2.80 Log(P) - 1.43 relationship between period > > and luminosity, and so on and so forth. > > Relativity has no explanation for the light curve of Algol. > The supposed eclipse is 10 hours in the period of 70 hours, > making 52 degrees in the 360 degree orbit. That places an upper > limit on the separation of the two bodies, 4.56 stellar radii of > the larger, the system is unstable and so on and so forth. > Please explain. Algol stellar parameters are well known, and there is NO problem with stability. You are making up a straw man argument. > > Please explain RU Cam in terms of BaT: > > -------------------------------------------- > > AAVSO Photoelectric Observations of RU Cam > > John R. Percy and Yvonne Tang > > RU Cam is a population II Cepheid which "stopped pulsating" > > in 1965-66. Actually, it did not stop pulsating completely; > > the amplitude decreased from over a magnitude to about 0.20, > > and remained stable at that level from 1967 to 1982, > > according to the work of Bela Szeidl and his colleagues. > > The period has fluctuated erratically between 17.4 and 26.6 > > days, but this may be the result of random, cycle-to-cycle > > fluctuations. As noted below, the HIPPARCOS satellite found > > a mean period and amplitude of 22.24 days and 0.20 magmitude, > > during its 3.5-year mission. > > http://www.aavso.org/observing/programs/pep/pepnewsletter/may1998/main.shtml > > > > Jerry > > That is hardly a proof that c+v is incorrect, Jerry. Arthur, RU Cam was discovered to be a variable in 1907. For almost 60 years, it showed classic Cepheid behavior. Then, starting in 1966, its pulsations started to slow down, until by 1970, they had nearly ceased. http://weblore.com/richard/ru_cam_ex_cepheid_star.htm > There could be many explanations, and often we never find > the correct one. Yeah. How about, "stars evolve"? How about, "Theory indicates that Cepheids pulsate for only a few hundred thousand years"? With thousands of Cepheids identified in a century of observation, we got lucky to catch one in transition. <snip> > We (well, you) obtain the following data from the AAVSO: > The light curve of Algol with Julian dates clearly provided, accurately > observed by multiple astronomers for the date chosen. > The velocity curve with the same Julian date clearly provided. > >From that, it should be possible to determine whether c constant or > c+v is the correct model. > Get the data, and I'll tell you how. Sorry, that's attempting to sidetrack me. Won't work. You have to figure out an answer to MY challenge first. Your only answer has been "There could be many explanations, and often we never find the correct one." In other words, YOU DON'T HAVE AN EXPLANATION. Come on, Arthur! What happened to the "binary" star RU Cam's orbit in 1966? This is critical to the survival of your c+v explanation of Cepheid behavior. The c+v explanation of Cepheid behavior has FAILED every challenge so far. To survive, it really needs to do a little better, don't you think? Jerry |