De Sitter's experiment and the relative motion of photons with respect to the surface of the star
in [Relativity]
|
From: Henry Wilson DSc on 4 Feb 2010 17:16 On Thu, 4 Feb 2010 11:29:08 -0800 (PST), PD <thedraperfamily(a)gmail.com> wrote: >On Feb 4, 10:24�am, ..@..(Henry Wilson DSc) wrote: >> On Thu, 4 Feb 2010 06:49:54 -0800 (PST), PD <thedraperfam...(a)gmail.com> wrote: >> >On Feb 4, 1:44�am, ..@..(Henry Wilson DSc) wrote: >> >> On Wed, 3 Feb 2010 22:05:12 -0800 (PST), Jerry <Cephalobus_alie...(a)comcast.net> >> >> wrote: >> >> >> >> Bull. Light speeds up as it falls. It follows a parabola in a moving frame just >> >> >> like any object would. >> >> >> . >> >> >> >> >What trajectory would be followed by an object >> >> >> >that passes by the Earth at greater than escape velocity? >> >> >> >> that's totally irrelevant. >> >> >> >HYPERBOLA HYPERBOLA HYPERBOLA HYPERBOLA HYPERBOLA >> >> >HYPERBOLA HYPERBOLA HYPERBOLA HYPERBOLA HYPERBOLA >> >> >HYPERBOLA HYPERBOLA HYPERBOLA HYPERBOLA HYPERBOLA >> >> >HYPERBOLA HYPERBOLA HYPERBOLA HYPERBOLA HYPERBOLA >> >> >HYPERBOLA HYPERBOLA HYPERBOLA HYPERBOLA HYPERBOLA >> >> >HYPERBOLA HYPERBOLA HYPERBOLA HYPERBOLA HYPERBOLA >> >> >HYPERBOLA HYPERBOLA HYPERBOLA HYPERBOLA HYPERBOLA >> >> >> we were talking about an object falling vertically downward. >> >> Diaper said it follows a parabolic path in a horizontally moving frame. >> >> >No, I didn't. Please reread what I said. >> >> This is what you said >> """"""""" >> �A ball falling from the top of the mast on a ship takes a >> straight line path in the frame of a ship, but a parabolic path in the >> �frame of the shore -- two different "results" regarding the same >> �events as seen in two different frames. > >Ah yes, my misread, apologies. that's OK. We're used to your mistakes... >A ball falling from the top of a mast on a ship does take a parabolic >path. > >> >> """""""" In future, when you copy something from an article, make sure you understand what it means. >> >> Henry Wilson... >> >> .......provider of free physics lessons Henry Wilson... ........provider of free physics lessons
From: Henry Wilson DSc on 4 Feb 2010 17:18 On Thu, 04 Feb 2010 12:48:25 -0800, eric gisse <jowr.pi.nospam(a)gmail.com> wrote: >..@..(Henry Wilson DSc) wrote: > >> On Wed, 03 Feb 2010 23:45:47 -0800, eric gisse <jowr.pi.nospam(a)gmail.com> >> wrote: >> >>>..@..(Henry Wilson DSc) wrote: >>> >>>> On Wed, 03 Feb 2010 22:15:26 -0800, eric gisse >>>> <jowr.pi.nospam(a)gmail.com> wrote: >> >>>>>>>Oh, come on, Henri! EVEN ASSUMING CLASSICAL MECHANICS, you would >>>>>>>be dead wrong. >>>>>> >>>>>> Bull. Light speeds up as it falls. >>>>> >>>>>Do you have any evidence for this, or is this just another one of your >>>>>personal feelings masquerading as 'science' ? >>>> >>>> Yes, the Pound-Rebka experiment. >>> >>>Pound-Rebka was a test of gravitational redshift, not whether or not light >>>speeds up as it falls. >>> >>>Do you have ANY EVIDENCE for your claim that light speeds up as it falls? >> >> Yes, the Pound-Rebka experiment. > >...did not actually show that light speeds up, or that it changes speed at >all. well, you can put an imaginary gradient in space if you want to prove your insanity. >Would you like to try again? > >> >>>>>Henri, how are people supposed to know that you are as smart as you >>>>>think you are when all you do is say stupid things? >>>> >>>> We are talking about an object falling vertically in one frame . It >>>> follows a parabola in a horizontally moving frame. Diaper didn't want to >>>> admit a light beam does the same. >>> >>>Because it doesn't. Light does not accelerate. >>> >>>I'll pre-comment on your sputtering: you have no evidence that light >>>travels at anything other than c, while I have an abundance of evidence >>>that it does not. >> >> Light travels at c wrt its source. > >...and everything else. > >> >>>>>http://groups.google.com/group/sci.physics.relativity/msg/65d8fac94b6e4d61?dmode=source >>>>> >>>>>"A cepheid curve is similar to that of a star in orbit with yaw between >>>>>about 50 and 80 and ecc around 2-3. there are plenty like that. " >>>> >>>> That's right. >>> >>>Glad to know you stand by the things you say, no matter how stupid they >>>are. >>> >>>Closed orbits do not exist for eccentricities larger than 1 >> >> 0.2-0.3 of course. > >Why 'of course', Henri? You say stupid things all the time with all earnest >- why should this time be any different? > >> >> >> >> Henry Wilson... >> >> .......provider of free physics lessons Henry Wilson... ........provider of free physics lessons
From: Henry Wilson DSc on 4 Feb 2010 17:20 On Thu, 4 Feb 2010 08:39:45 -0800 (PST), train <gehan.ameresekere(a)gmail.com> wrote: >On Feb 4, 9:29�pm, ..@..(Henry Wilson DSc) wrote: >> On Thu, 4 Feb 2010 06:51:24 -0800 (PST), PD <thedraperfam...(a)gmail.com> wrote: >> >On Feb 4, 5:23�am, train <gehan.ameresek...(a)gmail.com> wrote: >> >> On Feb 4, 7:45�am, PD <thedraperfam...(a)gmail.com> wrote: >> >> >> > > OK so instead of a ball, how about a photon emitted downwards from the >> >> > > mast of the ship? >> >> > > A parabolic path? Not so. >> >> >> > In a falling frame, yes! But not in the case you mention. >> >> >> > > A straight path downwards? Or an angled >> >> > > path ? >> >> >> > And again, note what I showed you about transformation of velocities. >> >> > The same law may be in effect, but this does not mean that you should >> >> > expect the same results. Recall that for bodies with v<c, transforming >> >> > velocities changes the value of v. But for v=c, the very same >> >> > transformation law does not change the value of v. >> >> >> > It is simply improper to expect that if there is a behavior governed >> >> > by a natural law for a ball, then we should expect the same behavior >> >> > for a photon, even if governed by the same natural law. >> >> >> > This is why it is important to know what the LAWS are, not just the >> >> > superficial behaviors. >> >> >> So one law for light, another law for non - light objects >> >> >Nope. Same law. Different results. >> >See AGAIN what I showed you about velocity transformation. >> >Same law -- different results for light and non-light objects. >> >> ...and are the fairies involved again? >> >> Henry Wilson... >> >> .......provider of free physics lessons > >It occurred to me, Henri, that when 'gravity bends light' this means >that there is an acceleration taking place. It also means that photons >have mass? Or does it? Maybe a person giving physics lessons can help >answer these. It doesn't have to possess mass. What IS 'mass' anyway? Henry Wilson... ........provider of free physics lessons
From: Henry Wilson DSc on 4 Feb 2010 17:24 On Thu, 4 Feb 2010 11:32:13 -0800 (PST), PD <thedraperfamily(a)gmail.com> wrote: >On Feb 4, 10:29�am, ..@..(Henry Wilson DSc) wrote: >> On Thu, 4 Feb 2010 06:51:24 -0800 (PST), PD <thedraperfam...(a)gmail.com> wrote: >> >On Feb 4, 5:23�am, train <gehan.ameresek...(a)gmail.com> wrote: >> >> On Feb 4, 7:45�am, PD <thedraperfam...(a)gmail.com> wrote: >> >> >> > > OK so instead of a ball, how about a photon emitted downwards from the >> >> > > mast of the ship? >> >> > > A parabolic path? Not so. >> >> >> > In a falling frame, yes! But not in the case you mention. >> >> >> > > A straight path downwards? Or an angled >> >> > > path ? >> >> >> > And again, note what I showed you about transformation of velocities. >> >> > The same law may be in effect, but this does not mean that you should >> >> > expect the same results. Recall that for bodies with v<c, transforming >> >> > velocities changes the value of v. But for v=c, the very same >> >> > transformation law does not change the value of v. >> >> >> > It is simply improper to expect that if there is a behavior governed >> >> > by a natural law for a ball, then we should expect the same behavior >> >> > for a photon, even if governed by the same natural law. >> >> >> > This is why it is important to know what the LAWS are, not just the >> >> > superficial behaviors. >> >> >> So one law for light, another law for non - light objects >> >> >Nope. Same law. Different results. >> >See AGAIN what I showed you about velocity transformation. >> >Same law -- different results for light and non-light objects. >> >> ...and are the fairies involved again? > >Not at all. A few lines of arithmetic using the same law in the two >cases show it. >Do you think a few lines of arithmetic is mysterious enough to >attribute the results to fairies? In SR, the same equation applies to both light and anything else. > >> >> Henry Wilson... >> >> .......provider of free physics lessons Henry Wilson... ........provider of free physics lessons
From: Henry Wilson DSc on 4 Feb 2010 17:32
On Thu, 4 Feb 2010 09:18:06 -0800 (PST), mpalenik <markpalenik(a)gmail.com> wrote: >On Feb 4, 11:39�am, train <gehan.ameresek...(a)gmail.com> wrote: >> On Feb 4, 9:29�pm, ..@..(Henry Wilson DSc) wrote: >> >> > >Nope. Same law. Different results. >> > >See AGAIN what I showed you about velocity transformation. >> > >Same law -- different results for light and non-light objects. >> >> > ...and are the fairies involved again? >> >> > Henry Wilson... >> >> > .......provider of free physics lessons >> >> It occurred to me, Henri, that when 'gravity bends light' this means >> that there is an acceleration taking place. It also means that photons >> have mass? Or does it? Maybe a person giving physics lessons can help >> answer these. > >No, it doesn't mean that photons have mass. The first answer I to >this question is that photons are actually traveling along straight >lines through curved space. ....ask your nurse for your pills please. >So in that sense, the force on the >photons (or anything in a gravitational field) is zero (meaning that >the covariant derivative of momentum is zero). > >A slightly more useful answer, however, that holds even outside the >framework of GR is that momentum is defined as dP/dt. It is the >change in momentum with respect to time. Although photons do not have >mass, they do have momentum and a force can thus, act on a photon to >change its momentum. > >In special relativity, there is an invariant quantity E^2 - P^2c^2, >which is equal to mc^2. E^2 - P^2c^2 does not change, no matter what >frame you measure it in. For Photons, since m = 0, you get E^2 = >P^2c^2, or E = Pc. SR is not the sole owner of that relationship Henry Wilson... ........provider of free physics lessons |