Speed of Light: A universal Constant?
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From: Henri Wilson on 14 Jun 2005 20:20 On Tue, 14 Jun 2005 02:08:53 +0000 (UTC), bz <bz+sp(a)ch100-5.chem.lsu.edu> wrote: >H@..(Henri Wilson) wrote in >news:lr4sa1da45qdlencsf6j9f97tchcr34ksg(a)4ax.com: > >> Just run my program again and see how it produces the exact >> characteristics of RT Aurigae. >> >> I have set the parameters to the right values. >> Set the distance to about 130-140 LYs using 'pause/ restart'. >> >> Then compare the brightness curves with the reference Andersen provided: >> http://mb-soft.com/public2/cepheid.html >> >> > >Unless you have your radial velocity (I am guessing that that is the blue >curve you have added) upside down, you have a problem. > >radial velocity from the referenced page has a slow increase and a rapid >retreat. You appear to have a rapid increase and a slow retreat. > >Even if your velocity curve is upside down, there is still a problem. Both my curves are upside down. Just invert them both. They match perfectly. > >The brightness curve lags behind the minimum of the radial velocity curve >in the real data. >In your curves, they come at the same time. This could be a crucial >difference. The paper is very confusing because the 'absolute' velocity curve is used. The BaT predictions are that the phase actually changes with distance. Initially the brightness peak leads the velocity peak. At greater distances it will catch up. I am presently looking into this because THe RT Aur curves are the first decent ones I have. I wish I could get a figure on distance for this star. > >I would also like to get the data from your program output into a file so I >can compare it using other programs with the table from the Anderson >provided reference. You have to use the relative velocity scale. ...subtract the 21 km/s. The graphs are still very confusing because the notes at the bottom claim that the maximum brightness occurs before the star has even reached half maximum size (36% of the cycle). Something doesn't quite add up here. > >If I had your latest code, I can get the data. I am still working on it. I have redefined the yaw angle zero (rotated it 90 deg to conform and make life easier) so all my past figures are now out by 90. 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: Paul B. Andersen on 15 Jun 2005 03:43 Henri Wilson wrote: > On Tue, 14 Jun 2005 11:29:18 +0200, "Paul B. Andersen" > <paul.b.andersen(a)deletethishia.no> wrote: > > >>Henri Wilson wrote: >> >>>On Mon, 13 Jun 2005 10:29:05 +0200, "Paul B. Andersen" >>><paul.b.andersen(a)deletethishia.no> wrote: >>> >>> >>> >>>>Henri Wilson wrote: > > >>>That has been explained to you a thousand times. >>> >>>Now....... HoHoHohahahahaha! >> >>And what the explanation is that your program >>doesn't work for real binaries where the orbital >>parameters are measured? :-) > > > It works perfectly. I see. And the one time you tried to enter actual data into your program it predicted that the binary HD80715 should be a variable. It isn't. >>>Please compare the BaT predictions for RTAur with your reference: >>> >>>Just run my program again and see how it produces the exact characteristics of >>>RT Aurigae. >>> >>>I have set the parameters to the right values. >>>Run the distance to about 130-140 LYs. >>>Then compare what you see with the reference you provided: >>>http://mb-soft.com/public2/cepheid.html >> >>.. but you insist that your program does works for imaginary >>binaries where you have invented the orbital parametres in >>such a way that the the Cepheid is orbiting a star within itself? >>Some program, eh? :-) > > > You haev sasked me to show how the program predicts from actual figures. > Just compare the predictions for RT Aur with the curves you provided. Indeed I have. So what are the "actual data" for RT Aur you entered into your program? How was those "actual data" measured? Paul
From: Paul B. Andersen on 15 Jun 2005 04:14 Henri Wilson wrote: > On Tue, 14 Jun 2005 08:53:16 +0000 (UTC), bz <bz+sp(a)ch100-5.chem.lsu.edu> > wrote: > > >>H@..(Henri Wilson) wrote in >>news:p1fsa1pt24bmi2c83ha9t314o9pm1snhdf(a)4ax.com: >> > > >>>>>>>Paul, Earth is about 100 solar diameters from the sun. >>>>>>> >>>>>>>The sun 'orbits the Earth' in one day. >>>>>> >>>>>>??? >>>>>> >>>>>>The earth rotates on its axis in one day. The sun does NOT orbit the >>>>>>earth any more than the entire universe orbits the earth every 24 >>>>>>hours. >>>>> >>>>>Bob, Did you notice the ' ' ? >>>> >>>>I did, but you were talking about a star orbiting in 5 days, implying >>>>that was possible because the sun orbited the earth in 24 hours. >>>> >>>> >>>>>I was merely trying to provide a visual impression of an object >>>>>orbiting another once per day. A large object orbiting every five >>>>>days, eg D Cep, would move a lot slower than that. >>>> >>>>Your image failed because to orbit in 24 hours, the sun would have had >>>>to be in synchronous orbit altitude at 22,235 miles. Which would kinds >>>>scorce my grass. >>> >>>Orbit diameter depends on the mass of the other object. >>> >>>Bob, my only concern was the apparent rate of movement, the angular >>>velocity of something in a 1 day orbit. The sun doesn't appear to move >>>very fast. >> >>The apparant angular velocity due to OUR rotation can not be counted. A 24 >>hour orbit will be at a radius of 22,235 miles. >> >>http://en.wikipedia.org/wiki/Orbital_period >>The orbital period depends on the masses involved, the semi major axis, and >>the universal constant G. >>P=2 pi sqrt(a^3/(G(M1+M2))) >> >>solving for 'a' gives >>a=1/(2 pi) 2^(1/3) (P^2 G(M1+M2) pi)^(1/3) >> >>With the mass of the sun as 1.9891E+30*kg and the mass of the earth >>5.9742E+24*kg, a 24 hour orbit is at 2.928E+6*km and the diameter of the >>sun is 1.392E+6*km, so it would be theoretically possible for the earth to >>orbit the sun in 24 hours. It would need to move at 213 km/s (7.1E-4 c) >>(assuming a circular orbit) in order to do so >> >>But two stars the mass of the sun would have to orbit each other at 3.6E6 >>KM at 268 km/s (8.9e-4 c). > > > Look Bob, I am genuinely sorry for causing this confusion. I thought you had > more brains that Andersen. > > I was merely pointing out that ANYTHING orbiting YOU once per day would appear > to move at the same angular velocity as our sun (or moon) does as it APPEARS TO > 'orbit' us. This was purely to illustrate the visual impression and had nothing > to do with the maths of different sized objects. It's always entertaining to see Henri trying to explain why his giant blunders are no blunders. :-) The context is that I pointed out the fact that if a mass with zero diameter was orbiting delta Cep, skimming its surface, the mass had to be 28 solar masses. To refute this fact, Henry wrote: | Paul, Earth is about 100 solar diameters from the sun. | | The sun 'orbits the Earth' in one day. | Something 40 times bigger orbiting every five days would not appear to move | very quickly, as seen by an observer on Earth. | If Jupiter was even five times larger, it would cause the sun, no matter how | big it might become to orbit around the barycentre at quite a large radius. | | D Cep doesn't need a neutron star as its companion, at all. Note the conclusion. The star Delta Cep is orbiting doesn't have to be very massive at all. Henry will of course now claim that when he said that D Cep didn't need to orbit a neutron star, he didn't mean that the star didn't have to be very massive, but that it can be another kind of very heavy massive - like a dark matter star. Because he will never admit that he made the blunder everybody can see that he did. Will you Henri? :-) Paul, enjoing the show > > >>>Use the moon if you want to be happy about it. It moves at about the >>>same angular speed. >> >>Not at all, it orbits in 28 days. You MUST separate the apparent motion due >>to the earths rotation. The earths rotation must be disregarded. > > > To somebody standing on Earth, it still APPEARS to move across the sky at about > the same speed as the sun. Do you dispute that? > > >>>>>The sun orbits the Earth/sun barycentre once per year. It also orbits >>>>>the Jupiter/sun barycentre once per Jupiter year. >>>> >>>>>If the sun had a large close companion, the two would orbit the >>>>>barycentre at the common period. >>>> >>>>Provided the orbits were circular or close thereto. >>> >>>No, the period would be the same for both, no matter what the >>>eccentricity.. >> >>correct. >> >> >>>I want to know more about the orbit shape though. > > > > 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: Paul B. Andersen on 15 Jun 2005 04:26 Henri Wilson wrote: > On Tue, 14 Jun 2005 14:38:28 +0200, "Paul B. Andersen" > <paul.b.andersen(a)deletethishia.no> wrote: > > >>Henri Wilson wrote: >> >>>On Mon, 13 Jun 2005 08:47:29 +0000 (UTC), bz <bz+sp(a)ch100-5.chem.lsu.edu> >>>wrote: >>> >>> >>> >>>>H@..(Henri Wilson) wrote in >>>>news:jtkpa1hu4tuk4ik1dtp62t42ro69d82jde(a)4ax.com: >>>> >>>> >>>> >>>>>Paul, Earth is about 100 solar diameters from the sun. >>>>> >>>>>The sun 'orbits the Earth' in one day. >>>> >>>>??? >>>> >>>>The earth rotates on its axis in one day. The sun does NOT orbit the earth >>>>any more than the entire universe orbits the earth every 24 hours. >>> >>> >>>Bob, Did you notice the ' ' ? >>> >>>I was merely trying to provide a visual impression of an object orbiting >>>another once per day. A large object orbiting every five days, eg D Cep, would >>>move a lot slower than that. >>> >>>The sun orbits the Earth/sun barycentre once per year. It also orbits the >>>Jupiter/sun barycentre once per Jupiter year. >>> >>>If the sun had a large close companion, the two would orbit the barycentre at >>>the common period. >> >>Quite. >>And this obviously explains how the 40 solar diameter delta Cep >>and a star which hasn't got to be a neutron star at all, >>can orbit their barycentre in the common period five days. > > > The other star is some kind of WCH....just like the one near RT Aur. So when you said: | Paul, Earth is about 100 solar diameters from the sun. | | The sun 'orbits the Earth' in one day. | Something 40 times bigger orbiting every five days would not appear to move | very quickly, as seen by an observer on Earth. | If Jupiter was even five times larger, it would cause the sun, no matter how | big it might become to orbit around the barycentre at quite a large radius. | | D Cep doesn't need a neutron star as its companion, at all. You didn't mean to point out that Delta Cep doesn't need a very massive star as its companion, at all? :-) That IS clear from the context, isn't it? :-) Paul
From: David Evens on 15 Jun 2005 05:10
On Sun, 12 Jun 2005 21:00:03 GMT, The Ghost In The Machine <ewill(a)sirius.athghost7038suus.net> wrote: >In sci.physics, Paul B. Andersen ><paul.b.andersen(a)deletethishia.no> > wrote >on Sun, 12 Jun 2005 21:33:22 +0200 ><d8i2m7$50d$1(a)dolly.uninett.no>: >> The Ghost In The Machine wrote: >>> In sci.physics, Paul B. Andersen >>> <paul.b.andersen(a)deletethishia.no> >>> wrote >> >>>>>On Thu, 09 Jun 2005 15:01:53 +0200, "Paul B. Andersen" >>>>><paul.b.andersen(a)deletethishia.no> wrote: >>>>> >>>>>>A star is basically a spherical black body emitting >>>>>>a black body spectrum. So the emitted power per surface >>>>>>area is W = sigma*T^4, sigma = Stefan-Boltzmann constant. >>>>>>When the temperature and emitted power is known, >>>>>>the surface area and thus the diameter of the star can >>>>>>be calculated. >>> >>> >>> Assuming, of course, that a star is in fact a spherical >>> thermal black body. (I'd say that's a fairly safe assumption, >>> myself. :-) >> >> It will not be strictly spherical if it is rotating, >> of course. > >Of course. But this is presumably a first-order approx... > >> >>> However, I'd have to look at what photons are >>> emitted from the H -> He reaction, and it may depend on >>> which cycle the star uses.) >> >> The fusion emits gamma radiation. But that happens in >> the core, and these photons do not go far before they are >> absorbed. New photons are emitted - and absorbed. >> It takes in the order of a million years for the energy >> to get from the core to the surface of the star. >> The star radiates its energy as a black body in >> the photosphere. The temperature is what it has to be >> to radiate as much energy as is produced in the fusion. > >There's also the issue of pressure -- which I'd not >originally thought of applying to the problem. Crudely >put, the star wants to contract to a point (or near point), >whereas the fusion wants to explode. Things balance out >just so, not unlike thermal equilibrium, though presumably >harder to calculate. > >> >> [..] >> >>>>So we have an invisible star with hundreds of solar masses. >>>>Such stars do not exist. >>> >>> >>> Black holes do. Admittedly, I for one would find a black >>> hole nearly touching a glowing M1- or M2-mass star >>> extremely unlikely without many highly noticeable effects, >>> a la Cygnus X-1. >>> >>> I mention this mostly for completeness. >> >> Then think about this: >> How could a 100 solar mass black hole be created? >> When a black hole is created from a collapsing star, >> its mass will be but few solar masses. >> If such an animal exists, it certainly isn't as >> a component of a binary. >> (But who knows what may lurk in the centre of >> some globular clusters?) > >Or for that matter at the center of galaxies? However, >I think you're generally correct; if a 5 M_sun or so star >is near a 100 M_sun or so black hole, it'll probably be >ripped apart and eaten -- assuming that the black hole's >creation explosion didn't simply disperse the gas of the >companion star somehow in the first place. However, I'd >have to look regarding said formation, and I know very >little regarding the actual math beyond Chankdreksahr's >Limit being about 1.5 M_sun. As was previously noted, you don't GET any stars that can colapse to form a 100-solar mass black hole, because it is phsically impossible for stars heavy enough to do so to form. The maximum mass for a star is somewhere between 30 and 50 solar masses. It has been determined, as well, that even the most massive stars blow off HUGE portions of their matter when they collapse into black holes. A 30-solar mass star, for instance, colapsing into a black hole blows off the equivalent of an entire solar mass just as gamma rays. (This is what we finally know to be the source of gamma ray bursts, and we can consider ourselves fortunate to not have any such superheavy stars in the immediate neighbourhood, since one of these going of with a few tens kiloparsecs is a bad day for the homeworld.) >Considering that Cepheids are extremely plentiful and >relatively uniform they can't be created in too weird >a fashion; Ockham's Razor would have a fit. :-) The most >logical from my standpoint is that there's more gas >than our Sun formed out of, and therefore we get a >more massive single star. > >> >> But anyway - as you say - a 100 solar masses black >> hole in the close vicinity of a Cepheid would make >> it presence very obvious. > >I should think so, not because of anything the black >hole per se is doing, but because space gets so >curved the gasses swirl into the hole and get very hot. > >> >>>>And you think you by repeating "puffing and blowing" over and over >>>>can make it ridiculous that a standing wave has a stable period? :-) >>> >>> >>> Who says they have a constant period anyway? I suspect they slowly >>> change -- *very* slowly, but I don't have the theory handy -- >>> as the hydrogen is converted to helium and the density/characteristics >>> of the star gas change. >> >> The period is NOT constant for eternity. Cepheids are stars which >> have left the main sequence and passes through the instability >> strip of the HR-diagram on their way to their death. >> But we are talking about millions of years on this journey, >> so most Cepheids will appear very regular for the century or >> so we have observed (some of) them. >> Polaris is an exception - the last century happens to be the >> time when it leaves the instability strip. It is hardly >> a Cepheid any more. >> >>> At some point a Cepheid will, quite literally, run out of gas. >>> (Just like all the others, only different. :-) ) >> >> See: >> http://www.astro.livjm.ac.uk/courses/one/NOTES/Garry%20Pilkington/loc.htm > >Interesting, and slightly weird. But then, the Universe is >normal; *we* are the weird ones (postulating at one point, >for example, that the Sun orbited around the Earth and >was carried by a chariot). > >> Specifically the animated figure showing a star's journey >> from the main sequence to its death - passing through >> the instability strip twice - and thus being a Cepheid twice. >> >> >>>>The Cepheid RT Aurigae with period 3.72 days, have a maxum >>>>surface velocity 17 km/s. The escape velocity is 200 km/s. >>>>So why would there be "bits of gas flying everywhere"? :-) >>> >>> >>> Well, there would be moving bits of gas, anyway. I'll admit to >>> wondering whether we can detect the movement with a sufficiently >>> sensitive spectroscope. >> >> Indeed we can. It is routine. > >Somehow, that doesn't surprise me. My ignorance is considerable >here, but it is nothing compared to someone else's... :-) > >> The pulsation is measured as a periodic variation in >> the radial velocity of the star. >> How did you think the surface velocity of RT Aurigae >> cited above was measured? >> http://mb-soft.com/public2/cepheid.html > >I'm not that familiar with spectroscopy so can't say of my own accord, >but looks straightforward enough. > >> >> Paul |