CMBR's motion wrt the Earth
in [Relativity]
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From: mluttgens on 8 Sep 2009 07:07 On 7 sep, 20:15, PD <thedraperfam...(a)gmail.com> wrote: > On Sep 6, 7:53 am, mluttgens <mluttg...(a)orange.fr> wrote: > > > > > > > CMBR's motion wrt the Earth > > ------------------------------------------ > > > In cosmology, cosmic microwave background (CMB) radiation > > (also CMBR, CBR, MBR, and relic radiation) is a form of > > electromagnetic radiation filling the universe. > > (fromhttp://en.wikipedia.org/wiki/CMBR) > > > By measuring the amount of the dipole anisotropy (the bluest > > part of the sky is .0033 K hotter than average), we can determine > > the magnitude of the earth's motion with respect to the CMB: > > the earth is moving at a speed of 370 km/s in the direction > > of the constellation Virgo. > > (fromhttp://www.phy.duke.edu/~kolena/cmb.htm) > > > It (the CMBR) does move with respect to an object. > > (from PD <thedraperfam...(a)gmail.com>, Sep 5, 2009) > > > Clearly, the Earth moves wrt the CMBR. According to SR, > > reciprocally, the CMBR moves wrt the Earth. > > Can somebody explain how, physically, an electromagnetic > > radiation filling the universe can move relative to the Earth? > > > Marcel Luttgens > > I think you are confused about what relative motion means, Marcel. You > have in your head that motion is an absolute statement, as in either > something is in motion or it's not. This is not the case. > > If you have car and a stop sign and a fire hydrant, the car is in > motion relative to the stop sign, and the stop sign is in motion > relative to the car, and the fire hydrant is not in motion relative to > the stop sign, and the stop sign is not in relative to the fire > hydrant, and the fire hydrant is in motion relative to the car, and > the car is in motion relative to the fire hydrant. > > I think you have it in your head that if you have two objects A and B > and they are in relative motion, then this means that one of them is > in motion and the other is not. As in, A is in motion relative to B, > but B is not in motion relative to A. No, what I have in my head is that if A is in motion relative to the CMBR, it is impossible to physically demonstrate that the CMBR moves wrt A. Marcel Luttgens > > When you say that you don't believe the CMBR is in motion relative to > the earth, I believe you think this because you somehow believe the > CMBR is fixed and stationary in some absolute sense and so can't be in > any kind of motion, relative or not. I don't know where you got this > idea. > > PD
From: Albertito on 8 Sep 2009 07:23 On Sep 8, 12:07 pm, mluttgens <mluttg...(a)orange.fr> wrote: > On 7 sep, 20:15, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Sep 6, 7:53 am, mluttgens <mluttg...(a)orange.fr> wrote: > > > > CMBR's motion wrt the Earth > > > ------------------------------------------ > > > > In cosmology, cosmic microwave background (CMB) radiation > > > (also CMBR, CBR, MBR, and relic radiation) is a form of > > > electromagnetic radiation filling the universe. > > > (fromhttp://en.wikipedia.org/wiki/CMBR) > > > > By measuring the amount of the dipole anisotropy (the bluest > > > part of the sky is .0033 K hotter than average), we can determine > > > the magnitude of the earth's motion with respect to the CMB: > > > the earth is moving at a speed of 370 km/s in the direction > > > of the constellation Virgo. > > > (fromhttp://www.phy.duke.edu/~kolena/cmb.htm) > > > > It (the CMBR) does move with respect to an object. > > > (from PD <thedraperfam...(a)gmail.com>, Sep 5, 2009) > > > > Clearly, the Earth moves wrt the CMBR. According to SR, > > > reciprocally, the CMBR moves wrt the Earth. > > > Can somebody explain how, physically, an electromagnetic > > > radiation filling the universe can move relative to the Earth? > > > > Marcel Luttgens > > > I think you are confused about what relative motion means, Marcel. You > > have in your head that motion is an absolute statement, as in either > > something is in motion or it's not. This is not the case. > > > If you have car and a stop sign and a fire hydrant, the car is in > > motion relative to the stop sign, and the stop sign is in motion > > relative to the car, and the fire hydrant is not in motion relative to > > the stop sign, and the stop sign is not in relative to the fire > > hydrant, and the fire hydrant is in motion relative to the car, and > > the car is in motion relative to the fire hydrant. > > > I think you have it in your head that if you have two objects A and B > > and they are in relative motion, then this means that one of them is > > in motion and the other is not. As in, A is in motion relative to B, > > but B is not in motion relative to A. > > No, what I have in my head is that if A is in motion relative > to the CMBR, it is impossible to physically demonstrate that > the CMBR moves wrt A. > > Marcel Luttgens > > > > > When you say that you don't believe the CMBR is in motion relative to > > the earth, I believe you think this because you somehow believe the > > CMBR is fixed and stationary in some absolute sense and so can't be in > > any kind of motion, relative or not. I don't know where you got this > > idea. > > > PD You are right Marcel. CMBR conforms an absolute frame of reference in the sense that the sources that emitted those CMBR photons were so distant from us, that their respective angular positions have not changed a bit since the emission events to the absoption ones. I can rember a wonderful thread started by Henri Wilson in this very forum called "Why are the 'Fixed Stars' so FIXED?" http://groups.google.com/group/sci.physics.relativity/msg/82337144cdc010f9 Thanks
From: PD on 8 Sep 2009 08:09 On Sep 8, 6:02 am, mluttgens <mluttg...(a)orange.fr> wrote: > On 8 sep, 01:32, "Inertial" <relativ...(a)rest.com> wrote: > > > > > "mluttgens" <mluttg...(a)orange.fr> wrote in message > > >news:523b7307-93cc-44c3-940e-8bd1f368776e(a)h13g2000yqk.googlegroups.com.... > > > > On 7 sep, 14:22, "Inertial" <relativ...(a)rest.com> wrote: > > >> "mluttgens" <mluttg...(a)orange.fr> wrote in message > > > >>news:6e6cbfbb-70bb-4fa6-99c3-45f00c351fa7(a)w36g2000yqm.googlegroups.com... > > > >> > On 7 sep, 01:59, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > > >> >> mluttgens wrote: > > >> >> > Can somebody explain how, physically, an electromagnetic > > >> >> > radiation filling the universe can move relative to the Earth? > > > >> >> Your descriptions are insufficiently precise. There is no such thing > > >> >> as > > >> >> "The CMBR" -- the cosmic microwave background radiation is comprised > > >> >> of > > >> >> myriads of photons moving in all directions. This is not a "thing" in > > >> >> any normal sense, it is a vast collection of photons. > > > >> >> [For the purposes of this thread I'll ignore the quantum > > >> >> aspects of photons.] > > > >> >> What you are missing is the fact that measurement of "the earth's > > >> >> motion > > >> >> with respect to the CMBR" is really a measurement of the earth's speed > > >> >> relative to THE FRAME IN WHICH THE CMBR DIPOLE MOMENT IS ZERO [#].. > > >> >> This > > >> >> is not in any sense a "rest frame of the CMBR", because the CMBR is > > >> >> myriads of photons NONE of which are at rest in any frame. This is > > >> >> purely a statistical property of the collection of all the photons > > >> >> comprising the CMBR. > > > >> >> [#] Careful authors phrase it this way, not in the careless > > >> >> way you did. I have been phrasing it as "the CMBR dipole=0 > > >> >> frame" in this newsgroup for many years. > > > >> >> It is rather remarkable that there is such radiation apparently > > >> >> filling > > >> >> the universe (it has been observed interacting with distant stars and > > >> >> galaxies). This is quite strong evidence in support of the big bang > > >> >> cosmologies, and the synthesis known as the standard model of > > >> >> cosmology. > > >> >> There remain details still unknown, and some downright puzzles (dark > > >> >> matter, dark energy, ...). > > > >> >> Tom Roberts > > > >> > Thank you. > > > >> I would have assumed it was taken from the context of talking about > > >> frames, > > >> and absolute frames in particular, that 'the CMBR' was referring to what > > >> is > > >> sometimes called the CMBR rest frame (as described above by Tom). > > > >> > Do you consider that claiming (like Paul Draper and others) > > >> > that the CMBR moves wrt an object, makes sense? > > > >> It makes as much sense as an object moving wrt the CMBR. > > > > No, read what Tom Roberts said: > > > I did .. read what I said > > > > "The measurement of "the earth's motion with respect to the CMBR" > > > is really a measurement of the earth's speed relative to THE FRAME > > > IN WHICH THE CMBR DIPOLE MOMENT IS ZERO." > > > That's right > > > > He didn't say that the Earth has no motion wrt the CMBR, > > > Neither did I > > Then explain how the "radiation apparently filling the universe" > can move wrt the Earth. You have some really strange ideas, Marcel. First, it sounds like you imagine the universe as being a giant ball with a boundary, where the radiation filling the universe is like some fluid filling a ball and so stationary with respect to the boundary of the ball. The universe has no boundary, no center. Second, you still seem to have a problem understanding relative motion. If a boat and the ocean are in relative motion, then the boat is in motion relative to the ocean AND the ocean is in motion relative to the boat. It is NOT the case that only one of these should be considered to be in motion. > > Marcel Luttgens > > > > > > he only > > > gave his interpretation of such motion. > > > No .. he gave a more specific terminology for what we had simply been > > calling 'the CMBR' in this thread as a frame of reference .. he said that > > what one should technically be saying it "the frame where the CMBR dipole > > moment is zero". but that's pretty words, so i think its ok to continue > > using 'the CMBR' as a shorthand, as long as we all know what we mean > >
From: Inertial on 8 Sep 2009 08:28 "mluttgens" <mluttgens(a)orange.fr> wrote in message news:afd5827b-f14e-4a66-a511-8148bb696967(a)g19g2000yqo.googlegroups.com... > On 8 sep, 01:32, "Inertial" <relativ...(a)rest.com> wrote: >> "mluttgens" <mluttg...(a)orange.fr> wrote in message >> >> news:523b7307-93cc-44c3-940e-8bd1f368776e(a)h13g2000yqk.googlegroups.com... >> >> >> >> >> >> > On 7 sep, 14:22, "Inertial" <relativ...(a)rest.com> wrote: >> >> "mluttgens" <mluttg...(a)orange.fr> wrote in message >> >> >>news:6e6cbfbb-70bb-4fa6-99c3-45f00c351fa7(a)w36g2000yqm.googlegroups.com... >> >> >> > On 7 sep, 01:59, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: >> >> >> mluttgens wrote: >> >> >> > Can somebody explain how, physically, an electromagnetic >> >> >> > radiation filling the universe can move relative to the Earth? >> >> >> >> Your descriptions are insufficiently precise. There is no such >> >> >> thing >> >> >> as >> >> >> "The CMBR" -- the cosmic microwave background radiation is >> >> >> comprised >> >> >> of >> >> >> myriads of photons moving in all directions. This is not a "thing" >> >> >> in >> >> >> any normal sense, it is a vast collection of photons. >> >> >> >> [For the purposes of this thread I'll ignore the quantum >> >> >> aspects of photons.] >> >> >> >> What you are missing is the fact that measurement of "the earth's >> >> >> motion >> >> >> with respect to the CMBR" is really a measurement of the earth's >> >> >> speed >> >> >> relative to THE FRAME IN WHICH THE CMBR DIPOLE MOMENT IS ZERO [#]. >> >> >> This >> >> >> is not in any sense a "rest frame of the CMBR", because the CMBR is >> >> >> myriads of photons NONE of which are at rest in any frame. This is >> >> >> purely a statistical property of the collection of all the photons >> >> >> comprising the CMBR. >> >> >> >> [#] Careful authors phrase it this way, not in the careless >> >> >> way you did. I have been phrasing it as "the CMBR dipole=0 >> >> >> frame" in this newsgroup for many years. >> >> >> >> It is rather remarkable that there is such radiation apparently >> >> >> filling >> >> >> the universe (it has been observed interacting with distant stars >> >> >> and >> >> >> galaxies). This is quite strong evidence in support of the big bang >> >> >> cosmologies, and the synthesis known as the standard model of >> >> >> cosmology. >> >> >> There remain details still unknown, and some downright puzzles >> >> >> (dark >> >> >> matter, dark energy, ...). >> >> >> >> Tom Roberts >> >> >> > Thank you. >> >> >> I would have assumed it was taken from the context of talking about >> >> frames, >> >> and absolute frames in particular, that 'the CMBR' was referring to >> >> what >> >> is >> >> sometimes called the CMBR rest frame (as described above by Tom). >> >> >> > Do you consider that claiming (like Paul Draper and others) >> >> > that the CMBR moves wrt an object, makes sense? >> >> >> It makes as much sense as an object moving wrt the CMBR. >> >> > No, read what Tom Roberts said: >> >> I did .. read what I said >> >> > "The measurement of "the earth's motion with respect to the CMBR" >> > is really a measurement of the earth's speed relative to THE FRAME >> > IN WHICH THE CMBR DIPOLE MOMENT IS ZERO." >> >> That's right >> >> > He didn't say that the Earth has no motion wrt the CMBR, >> >> Neither did I > > Then explain how the "radiation apparently filling the universe" > can move wrt the Earth. If its radiation, it moves at c relative to us, and relative to any other object. But the CMBR frame, the one we move at ~370km/s within, is the frame of reference where the "CMBR DIPOLE MOMENT IS ZERO" (to quote Tom's caps from above). We move at 370km/s relative to it, and so it moves at 370km/s relative to us. Please try and understand the terminology and basic physics here. Its not that hard.
From: Inertial on 8 Sep 2009 08:31
"Albertito" <albertito1992(a)gmail.com> wrote in message news:e18d05b1-bd58-4d12-8f0a-9b68f49997e5(a)o41g2000yqb.googlegroups.com... > On Sep 8, 12:07 pm, mluttgens <mluttg...(a)orange.fr> wrote: >> On 7 sep, 20:15, PD <thedraperfam...(a)gmail.com> wrote: >> >> >> >> > On Sep 6, 7:53 am, mluttgens <mluttg...(a)orange.fr> wrote: >> >> > > CMBR's motion wrt the Earth >> > > ------------------------------------------ >> >> > > In cosmology, cosmic microwave background (CMB) radiation >> > > (also CMBR, CBR, MBR, and relic radiation) is a form of >> > > electromagnetic radiation filling the universe. >> > > (fromhttp://en.wikipedia.org/wiki/CMBR) >> >> > > By measuring the amount of the dipole anisotropy (the bluest >> > > part of the sky is .0033 K hotter than average), we can determine >> > > the magnitude of the earth's motion with respect to the CMB: >> > > the earth is moving at a speed of 370 km/s in the direction >> > > of the constellation Virgo. >> > > (fromhttp://www.phy.duke.edu/~kolena/cmb.htm) >> >> > > It (the CMBR) does move with respect to an object. >> > > (from PD <thedraperfam...(a)gmail.com>, Sep 5, 2009) >> >> > > Clearly, the Earth moves wrt the CMBR. According to SR, >> > > reciprocally, the CMBR moves wrt the Earth. >> > > Can somebody explain how, physically, an electromagnetic >> > > radiation filling the universe can move relative to the Earth? >> >> > > Marcel Luttgens >> >> > I think you are confused about what relative motion means, Marcel. You >> > have in your head that motion is an absolute statement, as in either >> > something is in motion or it's not. This is not the case. >> >> > If you have car and a stop sign and a fire hydrant, the car is in >> > motion relative to the stop sign, and the stop sign is in motion >> > relative to the car, and the fire hydrant is not in motion relative to >> > the stop sign, and the stop sign is not in relative to the fire >> > hydrant, and the fire hydrant is in motion relative to the car, and >> > the car is in motion relative to the fire hydrant. >> >> > I think you have it in your head that if you have two objects A and B >> > and they are in relative motion, then this means that one of them is >> > in motion and the other is not. As in, A is in motion relative to B, >> > but B is not in motion relative to A. >> >> No, what I have in my head is that if A is in motion relative >> to the CMBR, it is impossible to physically demonstrate that >> the CMBR moves wrt A. >> >> Marcel Luttgens >> >> >> >> > When you say that you don't believe the CMBR is in motion relative to >> > the earth, I believe you think this because you somehow believe the >> > CMBR is fixed and stationary in some absolute sense and so can't be in >> > any kind of motion, relative or not. I don't know where you got this >> > idea. >> >> > PD > > You are right Marcel. CMBR conforms an absolute frame > of reference in the sense that the sources that emitted > those CMBR photons were so distant from us, that their > respective angular positions have not changed a bit since > the emission events to the absoption ones. It is a frame, but nothing absolute about it. The physics of that frame is the same as any other. It is a significant frame (especially to astronomers) > I can rember a wonderful thread started by Henri Wilson > in this very forum called "Why are the 'Fixed Stars' so FIXED?" > http://groups.google.com/group/sci.physics.relativity/msg/82337144cdc010f9 Oh gawd, not Henry. He has some weird ideas, and an amazing lack of understanding about physics, and ability to post untruths with apparently no remorse. |