Speed of Light: A universal Constant?
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From: G on 25 Apr 2005 03:30 "The light from the two sources does not move at the same single speed towards the whole of andromeda if the two sources are relatively moving. Why should it?" Dear Mr Wilson The speed of light is independant of the source, is it not? I can't see how the above statement could be true. Think of the speed of light as a messenger and the source as the message sender. There is only one way and one speed to send light at (relative to the sender), not matter what the source is doing. If you send a message and then move somewhere your message is not affected: If you make a phone call from a plane or a car or your house it does not make a difference to the speed at which the signale travels - can't everyone see this? What is the counter proof? If you shine a light and then move the source the original first photon or first wavefront emitted has no connection to the source and will not know or care what the source is doing. WIll have a look at the Sagnac: need to understand this G
From: The Ghost In The Machine on 25 Apr 2005 08:00 In sci.physics, G <gehan(a)dialog.lk> wrote on 25 Apr 2005 00:30:47 -0700 <1114414247.091326.33890(a)g14g2000cwa.googlegroups.com>: > "The light from the two sources does not move at the same > single speed towards the whole of andromeda if the two > sources are relatively moving. Why should it?" > > Dear Mr Wilson > > The speed of light is independant of the source, is it not? In BaT, lightspeed is c relative to the source, *not* to the destination (unless said destination is motionless relative to the source). In SR/GR, lightspeed is c everywhere. That's probably the primary difference between these two theories. > I can't see how the above statement could be true. Think of > the speed of light as a messenger and the source as the message > sender. You may be slightly confused. The speed of light is merely a measurement constant. If you're referring to the light *pulse* as being a message, that's fine. > There is only one way and one speed to send light at > (relative to the sender), not matter what the source is > doing. Depends on who's doing the observing, though you do have a point. But think of a river; a canoe launches in the river and can go 10 mph in still water, but if the river is moving 6 mph the canoe will either go 16 or 4 mph, depending on direction along the river. If the canoe is attempting to cross the river it will only be able to make 8 mph (as it has to traverse the hypotenuse of a triangle). > If you send a message and then move somewhere your > message is not affected: If you make a phone call from a > plane or a car or your house it does not make a difference > to the speed at which the signale travels - can't everyone > see this? That's just it: if one is sending a message from the ground at c, BaT assures us that the message as received by the *plane* will be at c + v, where v is the velocity of the plane relative to the ground. For its part SR twists time and space so that the plane will receive the light at c, though with a frequency shift (a shift moreover that is above and beyond the expected Doppler ratio (c+v)/c). > What is the counter proof? If you shine a light > and then move the source the original first photon or first > wavefront emitted has no connection to the source and will > not know or care what the source is doing. In most problems of this type the first photon fires from a source that is already moving. > > WIll have a look at the Sagnac: need to understand this It's an interesting effect; I for one will have to study it myself. Basically, it's a rotating ring. > > G > -- #191, ewill3(a)earthlink.net It's still legal to go .sigless.
From: G on 25 Apr 2005 08:51 Henry In the MMX how did they determine the speed for the ether relative to the earth.? It was known that the earth orbited the sun, therefore the earth was not at rest WRT the ether It was known that the Sun was not the centre of the universe and was moving relative to other stars. Therefore it was either at rest WRT to ether or it was not. If the SUN was not at rest WRT ether then how was it possible to measure the speed of the sun WRT to ether? Distant stars? Doesn't this impact the whole area of measurement of light from distant stars? Can someone shed some light G
From: Paul B. Andersen on 25 Apr 2005 09:58 Henri Wilson wrote: > On Sun, 24 Apr 2005 23:17:48 +0200, "Paul B. Andersen" > <paul.b.andersen(a)deletethishia.no> wrote: > > >>Henri Wilson wrote: >> >>>On Wed, 20 Apr 2005 16:45:21 +0200, "Paul B. Andersen" >>><paul.b.andersen(a)deletethishia.no> wrote: >>> > > >>>>then the angular velocity is (360deg/2N)/s, where N is >>>>the number of wavelengths around the ring. With a ring >>>>length of - say 25cm - and a wavelength of 0.5um we >>>>get that a rotation of 0.000360deg/s or 1.3deg/h will >>>>give a phase difference change of 360deg/s. >>>>Easily measurable, and the beauty of it is that this >>>>only depend on geometric parameters and not on >>>>any calibration done at some earlier time. >>>> >>>>I know that the inertial navigational systems in >>>>commercial and military aeroplanes all use ring lasers. >>> >>> >>>So what is the basic difference between a 'fibre optic' and a ring gyro? I >>>didn't know there was any. >> >>There is a fundamental difference between a fibre optic Sagnac ring >>and a ring laser gyro. I think I have told you before, >>and won't bother to repeat it. Look it up yourself. > > > I gather you don't know. http://www.google.no/groups?hl=no&lr=&selm=bagohm$9qq$1(a)dolly.uninett.no http://www.google.no/groups?hl=no&lr=&selm=bv5k3p$p2c$1(a)dolly.uninett.no http://www.google.no/groups?hl=&selm=baontp$ch0$1(a)dolly.uninett.no Paul
From: Henri Wilson on 25 Apr 2005 16:43
On Mon, 25 Apr 2005 15:58:51 +0200, "Paul B. Andersen" <paul.b.andersen(a)deletethishia.no> wrote: >Henri Wilson wrote: >> On Sun, 24 Apr 2005 23:17:48 +0200, "Paul B. Andersen" >> <paul.b.andersen(a)deletethishia.no> wrote: >> >> >>>Henri Wilson wrote: >>> >>>>On Wed, 20 Apr 2005 16:45:21 +0200, "Paul B. Andersen" >>>><paul.b.andersen(a)deletethishia.no> wrote: >>>> >> >> >>>>>then the angular velocity is (360deg/2N)/s, where N is >>>>>the number of wavelengths around the ring. With a ring >>>>>length of - say 25cm - and a wavelength of 0.5um we >>>>>get that a rotation of 0.000360deg/s or 1.3deg/h will >>>>>give a phase difference change of 360deg/s. >>>>>Easily measurable, and the beauty of it is that this >>>>>only depend on geometric parameters and not on >>>>>any calibration done at some earlier time. >>>>> >>>>>I know that the inertial navigational systems in >>>>>commercial and military aeroplanes all use ring lasers. >>>> >>>> >>>>So what is the basic difference between a 'fibre optic' and a ring gyro? I >>>>didn't know there was any. >>> >>>There is a fundamental difference between a fibre optic Sagnac ring >>>and a ring laser gyro. I think I have told you before, >>>and won't bother to repeat it. Look it up yourself. >> >> >> I gather you don't know. > >http://www.google.no/groups?hl=no&lr=&selm=bagohm$9qq$1(a)dolly.uninett.no >http://www.google.no/groups?hl=no&lr=&selm=bv5k3p$p2c$1(a)dolly.uninett.no >http://www.google.no/groups?hl=&selm=baontp$ch0$1(a)dolly.uninett.no > >Paul OK 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. |