Seeking a correct explanation for Stellar Abberation
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From: Inertial on 27 Mar 2010 06:36 "train" <gehan.ameresekere(a)gmail.com> wrote in message news:3df57f91-3000-4475-b243-fefb2293f1c1(a)h35g2000pri.googlegroups.com... > On Mar 26, 4:11 am, "Inertial" <relativ...(a)rest.com> wrote: >> "train" <gehan.ameresek...(a)gmail.com> wrote in message >> >> news:02d05217-670e-4373-a79d-48d3fc7d85c0(a)x23g2000prd.googlegroups.com... >> >> >> >> >> >> > On Mar 25, 4:23 am, "Inertial" <relativ...(a)rest.com> wrote: >> >> "train" <gehan.ameresek...(a)gmail.com> wrote in message >> >> >>news:3cbcfae1-4866-41aa-b30e-c7cba7a9ba5a(a)c20g2000prb.googlegroups.com... >> >> >> > On Mar 23, 5:47 am, ..@..(Henry Wilson DSc) wrote: >> >> >> On Mon, 22 Mar 2010 15:46:41 -0700, eric gisse >> >> >> <jowr.pi.nos...(a)gmail.com> >> >> >> wrote: >> >> >> >> >..@..(Henry Wilson DSc) wrote: >> >> >> >> >> On Tue, 23 Mar 2010 08:55:43 +1100, "Inertial" >> >> >> >> <relativ...(a)rest.com> >> >> >> >> wrote: >> >> >> >> >>>"Henry Wilson DSc" <..@..> wrote in message >> >> >> >>>news:32hfq5hus6nsjffnret3t2o0qgtoks0bdp(a)4ax.com... >> >> >> >>>> There are no LTs in the real >> >> >> >>>> world. >> >> >> >> >>>Just keep lying to yourself Henry. The only fool you are >> >> >> >>>fooling >> >> >> >>>is >> >> >> >>>you. >> >> >> >> >> Even an idiot like you should know that nothing at all happens >> >> >> >> to a >> >> >> >> rod or >> >> >> >> clock as a result of a speed change. >> >> >> >> >> A rod defines the same absolute spatial interval however and >> >> >> >> wherever >> >> >> >> it >> >> >> >> is taken. >> >> >> >> An oscillator period defines an absolute time interval, ditto. >> >> >> >> >A decade running and you haven't learned a damn thing. Nice. >> >> >> >> When are you going to say something intelligent? >> >> >> >> Henry Wilson... >> >> >> >> .......A person's IQ = his snipping ability. >> >> >> > Remember I was "Seekingacorrectexplanation for Stellar Abberation" >> >> >> > In contrast, stellar aberration is independent of the distance of a >> >> > celestial object from the observer, and depends only on the >> >> > observer's >> >> > instantaneous transverse velocity with respect to the incoming light >> >> > beam, at the moment of observation >> >> >> > Indeed, dependency on the source is paradoxical: >> >> >> And you snip from your quote the explanation for what you are asking >> >> >> > -Wikipedia >> >> >> > I understand that aberration is caused by relative velocity between >> >> > source and the telescope. >> >> >> No .. between arriving light beam and telescope. >> >> >> > There is no absolute motion in Galilean >> >> > Relativity not in SRT >> >> >> That's right .. relativity (in the sense of there being no absolute >> >> motion) >> >> has been around for a LONG time. >> >> >> > So why the 'dependency on the source?' >> >> >> There is none >> >> > No .. between arriving light beam and telescope. >> >> That only depends on the position of the light source at the time a given >> photon was emitted >> >> > Can you define light beam? >> >> It is the set of positions of all the photons at a given time >> >> > In any case, the light goes directly down the tube, >> >> Yes >> >> > which means that >> > the relative velocity of the photons or 'light beam' is parallel to >> > the telescope walls. So the relative velocity between the photons and >> > the telescope is c, or as others might say a little more than c >> >> Except when you put water in it .. and it slows down >> >> > What am I missing here? >> >> If the angle is due to the motion of the telescope wrt the normal to the > > OK >> light (eg that the telescope is moving to the right (say) as the photon >> is > > OK > >> travelling downward (say)) .. then slowing the light WILL change the >> angle > > You aim the telescope so the light goes down it. > > There is nothing in the experiment about 'slowing the light' How is > this done? > >> (as it will move downward by a smaller distance over the length of the >> telescope tube) and so it will no longer go directly down the tube (not >> parallel to it). We don't see that. >> >> If the angle is due to the photon being aimed directly toward a fixed >> telescope, then there is no change in angle if the photon changes speed >> .. >> it just travels slower down the tube at the same angle. That is what we >> observe .. the same results as if the telescope was fixed. >> >> Do you understand now? >
From: train on 27 Mar 2010 21:00 On Mar 27, 3:37 pm, "Inertial" <relativ...(a)rest.com> wrote: > "train" <gehan.ameresek...(a)gmail.com> wrote in message > > news:3df57f91-3000-4475-b243-fefb2293f1c1(a)h35g2000pri.googlegroups.com... > > > > > > > On Mar 26, 4:11 am, "Inertial" <relativ...(a)rest.com> wrote: > >> "train" <gehan.ameresek...(a)gmail.com> wrote in message > > >>news:02d05217-670e-4373-a79d-48d3fc7d85c0(a)x23g2000prd.googlegroups.com.... > > >> > On Mar 25, 4:23 am, "Inertial" <relativ...(a)rest.com> wrote: > >> >> "train" <gehan.ameresek...(a)gmail.com> wrote in message > > >> >>news:3cbcfae1-4866-41aa-b30e-c7cba7a9ba5a(a)c20g2000prb.googlegroups.com... > > >> >> > On Mar 23, 5:47 am, ..@..(Henry Wilson DSc) wrote: > >> >> >> On Mon, 22 Mar 2010 15:46:41 -0700, eric gisse > >> >> >> <jowr.pi.nos...(a)gmail.com> > >> >> >> wrote: > > >> >> >> >..@..(Henry Wilson DSc) wrote: > > >> >> >> >> On Tue, 23 Mar 2010 08:55:43 +1100, "Inertial" > >> >> >> >> <relativ...(a)rest.com> > >> >> >> >> wrote: > > >> >> >> >>>"Henry Wilson DSc" <..@..> wrote in message > >> >> >> >>>news:32hfq5hus6nsjffnret3t2o0qgtoks0bdp(a)4ax.com... > >> >> >> >>>> There are no LTs in the real > >> >> >> >>>> world. > > >> >> >> >>>Just keep lying to yourself Henry. The only fool you are > >> >> >> >>>fooling > >> >> >> >>>is > >> >> >> >>>you. > > >> >> >> >> Even an idiot like you should know that nothing at all happens > >> >> >> >> to a > >> >> >> >> rod or > >> >> >> >> clock as a result of a speed change. > > >> >> >> >> A rod defines the same absolute spatial interval however and > >> >> >> >> wherever > >> >> >> >> it > >> >> >> >> is taken. > >> >> >> >> An oscillator period defines an absolute time interval, ditto.. > > >> >> >> >A decade running and you haven't learned a damn thing. Nice. > > >> >> >> When are you going to say something intelligent? > > >> >> >> Henry Wilson... > > >> >> >> .......A person's IQ = his snipping ability. > > >> >> > Remember I was "Seekingacorrectexplanation for Stellar Abberation" > > >> >> > In contrast, stellar aberration is independent of the distance of a > >> >> > celestial object from the observer, and depends only on the > >> >> > observer's > >> >> > instantaneous transverse velocity with respect to the incoming light > >> >> > beam, at the moment of observation > > >> >> > Indeed, dependency on the source is paradoxical: > > >> >> And you snip from your quote the explanation for what you are asking > > >> >> > -Wikipedia > > >> >> > I understand that aberration is caused by relative velocity between > >> >> > source and the telescope. > > >> >> No .. between arriving light beam and telescope. > > >> >> > There is no absolute motion in Galilean > >> >> > Relativity not in SRT > > >> >> That's right .. relativity (in the sense of there being no absolute > >> >> motion) > >> >> has been around for a LONG time. > > >> >> > So why the 'dependency on the source?' > > >> >> There is none > > >> > No .. between arriving light beam and telescope. > > >> That only depends on the position of the light source at the time a given > >> photon was emitted > > >> > Can you define light beam? > > >> It is the set of positions of all the photons at a given time > > >> > In any case, the light goes directly down the tube, > > >> Yes > > >> > which means that > >> > the relative velocity of the photons or 'light beam' is parallel to > >> > the telescope walls. So the relative velocity between the photons and > >> > the telescope is c, or as others might say a little more than c > > >> Except when you put water in it .. and it slows down > > >> > What am I missing here? > > >> If the angle is due to the motion of the telescope wrt the normal to the > > > OK > >> light (eg that the telescope is moving to the right (say) as the photon > >> is > > > OK > > >> travelling downward (say)) .. then slowing the light WILL change the > >> angle > > > You aim the telescope so the light goes down it. > > And the angle will need to be different if filled with water > > > There is nothing in the experiment about 'slowing the light' > > Of course there is .. that was the whole POINT of it. > > > How is > > this done? > > Water > > >> (as it will move downward by a smaller distance over the length of the > >> telescope tube) and so it will no longer go directly down the tube (not > >> parallel to it). We don't see that. > > >> If the angle is due to the photon being aimed directly toward a fixed > >> telescope, then there is no change in angle if the photon changes speed > >> .. > >> it just travels slower down the tube at the same angle. That is what we > >> observe .. the same results as if the telescope was fixed. > > >> Do you understand now? In your opinion, Does aberration conflict with 1) Galilean Relativity 2) Special Relativity 3) The Ballistic theory of light 4) The Wave theory of light This is what I am getting at T
From: Inertial on 28 Mar 2010 19:36 "train" <gehan.ameresekere(a)gmail.com> wrote in message news:61579e48-1ef7-4536-926d-c100678f12a1(a)j16g2000prn.googlegroups.com... > On Mar 27, 3:37 pm, "Inertial" <relativ...(a)rest.com> wrote: >> "train" <gehan.ameresek...(a)gmail.com> wrote in message >> >> news:3df57f91-3000-4475-b243-fefb2293f1c1(a)h35g2000pri.googlegroups.com... >> >> >> >> >> >> > On Mar 26, 4:11 am, "Inertial" <relativ...(a)rest.com> wrote: >> >> "train" <gehan.ameresek...(a)gmail.com> wrote in message >> >> >>news:02d05217-670e-4373-a79d-48d3fc7d85c0(a)x23g2000prd.googlegroups.com... >> >> >> > On Mar 25, 4:23 am, "Inertial" <relativ...(a)rest.com> wrote: >> >> >> "train" <gehan.ameresek...(a)gmail.com> wrote in message >> >> >> >>news:3cbcfae1-4866-41aa-b30e-c7cba7a9ba5a(a)c20g2000prb.googlegroups.com... >> >> >> >> > On Mar 23, 5:47 am, ..@..(Henry Wilson DSc) wrote: >> >> >> >> On Mon, 22 Mar 2010 15:46:41 -0700, eric gisse >> >> >> >> <jowr.pi.nos...(a)gmail.com> >> >> >> >> wrote: >> >> >> >> >> >..@..(Henry Wilson DSc) wrote: >> >> >> >> >> >> On Tue, 23 Mar 2010 08:55:43 +1100, "Inertial" >> >> >> >> >> <relativ...(a)rest.com> >> >> >> >> >> wrote: >> >> >> >> >> >>>"Henry Wilson DSc" <..@..> wrote in message >> >> >> >> >>>news:32hfq5hus6nsjffnret3t2o0qgtoks0bdp(a)4ax.com... >> >> >> >> >>>> There are no LTs in the real >> >> >> >> >>>> world. >> >> >> >> >> >>>Just keep lying to yourself Henry. The only fool you are >> >> >> >> >>>fooling >> >> >> >> >>>is >> >> >> >> >>>you. >> >> >> >> >> >> Even an idiot like you should know that nothing at all >> >> >> >> >> happens >> >> >> >> >> to a >> >> >> >> >> rod or >> >> >> >> >> clock as a result of a speed change. >> >> >> >> >> >> A rod defines the same absolute spatial interval however and >> >> >> >> >> wherever >> >> >> >> >> it >> >> >> >> >> is taken. >> >> >> >> >> An oscillator period defines an absolute time interval, >> >> >> >> >> ditto. >> >> >> >> >> >A decade running and you haven't learned a damn thing. Nice. >> >> >> >> >> When are you going to say something intelligent? >> >> >> >> >> Henry Wilson... >> >> >> >> >> .......A person's IQ = his snipping ability. >> >> >> >> > Remember I was "Seekingacorrectexplanation for Stellar >> >> >> > Abberation" >> >> >> >> > In contrast, stellar aberration is independent of the distance of >> >> >> > a >> >> >> > celestial object from the observer, and depends only on the >> >> >> > observer's >> >> >> > instantaneous transverse velocity with respect to the incoming >> >> >> > light >> >> >> > beam, at the moment of observation >> >> >> >> > Indeed, dependency on the source is paradoxical: >> >> >> >> And you snip from your quote the explanation for what you are >> >> >> asking >> >> >> >> > -Wikipedia >> >> >> >> > I understand that aberration is caused by relative velocity >> >> >> > between >> >> >> > source and the telescope. >> >> >> >> No .. between arriving light beam and telescope. >> >> >> >> > There is no absolute motion in Galilean >> >> >> > Relativity not in SRT >> >> >> >> That's right .. relativity (in the sense of there being no absolute >> >> >> motion) >> >> >> has been around for a LONG time. >> >> >> >> > So why the 'dependency on the source?' >> >> >> >> There is none >> >> >> > No .. between arriving light beam and telescope. >> >> >> That only depends on the position of the light source at the time a >> >> given >> >> photon was emitted >> >> >> > Can you define light beam? >> >> >> It is the set of positions of all the photons at a given time >> >> >> > In any case, the light goes directly down the tube, >> >> >> Yes >> >> >> > which means that >> >> > the relative velocity of the photons or 'light beam' is parallel to >> >> > the telescope walls. So the relative velocity between the photons >> >> > and >> >> > the telescope is c, or as others might say a little more than c >> >> >> Except when you put water in it .. and it slows down >> >> >> > What am I missing here? >> >> >> If the angle is due to the motion of the telescope wrt the normal to >> >> the >> >> > OK >> >> light (eg that the telescope is moving to the right (say) as the >> >> photon >> >> is >> >> > OK >> >> >> travelling downward (say)) .. then slowing the light WILL change the >> >> angle >> >> > You aim the telescope so the light goes down it. >> >> And the angle will need to be different if filled with water >> >> > There is nothing in the experiment about 'slowing the light' >> >> Of course there is .. that was the whole POINT of it. >> >> > How is >> > this done? >> >> Water >> >> >> (as it will move downward by a smaller distance over the length of the >> >> telescope tube) and so it will no longer go directly down the tube >> >> (not >> >> parallel to it). We don't see that. >> >> >> If the angle is due to the photon being aimed directly toward a fixed >> >> telescope, then there is no change in angle if the photon changes >> >> speed >> >> .. >> >> it just travels slower down the tube at the same angle. That is what >> >> we >> >> observe .. the same results as if the telescope was fixed. >> >> >> Do you understand now? > > In your opinion, Does aberration conflict with > > 1) Galilean Relativity > 2) Special Relativity > 3) The Ballistic theory of light > 4) The Wave theory of light AFAIK The lack of change in angle when light slows does contradict ballistic theory .. light should just behave like raindrops falling, where a change in speed of the drops will change the angle. As far as light being a wave in the aether .. aberration also posed some problems for that theory, and was one of the reasons why the old aether theories were modified .. aether theory has changed many times and new experiments refute it. > This is what I am getting at I suggest you do some more reading on the subject of the water-filled telescope and stellar aberration, and the history of theories of light if you want to find out.
From: Paul B. Andersen on 29 Mar 2010 08:45 On 20.03.2010 01:04, Inertial wrote: > If light were simple ballistic particles, then if it was coming > from a moving (or stationary)source aimed at a stationary telescope, > then slowing it down would *not* change its angle. > > . <S> > . > . o > . > . > . / / > . > . / / > . > . / / > > . <S> > . > . > . > . o > . > . / / > . > . / / > . > . / / > > . <S> > . > . > . > . > . > . /o/ > . > . / / > . > . / / > > . <S> > . > . > . > . > . > . / / > . > . /o/ > . > . / / > > . <S> > . > . > . > . > . > . / / > . > . / / > . > . /o/ > > > If light were simple ballistic particles, then if it was coming > from a stationary source aimed at a moving telescope, > then slowing it down *would* change its angle. > > . <S> > . > . o > . > . > . / / > . > . / / > . > . / / > > . <S> > . > . > . > . o > . > . / / > . > . / / > . > . / / > > . <S> > . > . > . > . > . > . /o/ > . > . / / > . > . / / > > . <S> > . > . > . > . > . > . / / > . o > . / / > . > . / / > > . <S> > . > . > . > . > . > . / / > . > . o / > . > . / / > > . <S> > . > . > . > . > . > . / / > . > . / / > . o > . / / > > . <S> > . > . > . > . > . > . / / > . > . / / > . > . o/ / Hm. This is correct as it stands, but it rests on an assumption you may not be aware of. Not to nit-pick, but I asked myself these questions: What is the difference between the inertial "rest frame", and the inertial "moving telescope frame"? Why is the trajectory of the particle straight in the former but bent in the latter? Let me illustrate. In inertial frame A, a particle is going 'straight down', and is reducing its speed from v1 to v2. o o v1 o X o o v2 o The trajectory is a straight line in frame A. Frame B is moving 'horizontally' to the right at some speed v. In this frame the trajectory would look something like this this: o o o X o o o The trajectory is bent in frame B. Why? The point is that there is no such thing as 'reducing the speed of the particle along its direction of motion', because the direction of motion is frame dependent. So the important question is: What is the direction of the force that is acting on the particle? In frame A this force must be acting upwards opposite to the velocity of the particle. In frame B the force will still act vertically upwards, so it has an angle to the velocity of the particle, and will change the direction of the velocity as well as reducing the speed. The point is that if the speed of the particle is reduced by entering some medium, like a water filled telescope, the speed reducing force will act opposite to the velocity _in the telescope frame_, so the trajectory of the particle will be straight _in the telescope frame_. Your somewhat questionable assumption was that the speed reducing force was acting opposite to the velocity of the particle in the (arbitrary?) 'rest frame', and thus not in the 'moving telescope frame'. The speed of the source is in any case utterly irrelevant. -- Paul http://home.c2i.net/pb_andersen/
From: Paul B. Andersen on 29 Mar 2010 10:05
On 21.03.2010 03:06, train wrote: > On Mar 20, 5:04 am, "Inertial"<relativ...(a)rest.com> wrote: >> "train"<gehan.ameresek...(a)gmail.com> wrote in message >> >> >>> Ok here is a telescope >> >>> | | >>> | | >>> | | >>> | | >>> | | >>> | | >> >>> Here is the photon entering the telescope >> >>> 0 >>> | | >>> | | >>> | | >>> | | >>> | | >>> | | >> >>> | | >>> |0| >>> | | >>> | | >>> | | >>> | | >> >>> OK now did that photon come from a moving source (relative to the >>> telescope) or a stationary source (relative to the telescope) ? Impossible to say. The speed of the source is irrelevant. The velocity (direction) of the photon conveys no information about the velocity of its source. >> >> If it came from a star and is measured measured on earth, then we know that >> they are relatively moving. >> >> If light were simple ballistic particles, then if it was coming from a >> moving (or stationary)source aimed at a stationary telescope, then slowing >> it down would *not* change its angle. >> >> .<S> >> . >> . o >> . >> . >> . / / >> . >> . / / >> . >> . / / >> >> .<S> >> . >> . >> . >> . o >> . >> . / / >> . >> . / / >> . >> . / / >> >> .<S> >> . >> . >> . >> . >> . >> . /o/ >> . >> . / / >> . >> . / / >> >> .<S> >> . >> . >> . >> . >> . >> . / / >> . >> . /o/ >> . >> . / / >> >> .<S> >> . >> . >> . >> . >> . >> . / / >> . >> . / / >> . >> . /o/ >> >> If light were simple ballistic particles, then if it was coming from a >> stationary source aimed at a moving telescope, then slowing it down *would* >> change its angle. >> >> .<S> >> . >> . o >> . >> . >> . / / >> . >> . / / >> . >> . / / >> >> .<S> >> . >> . >> . >> . o >> . >> . / / >> . >> . / / >> . >> . / / >> >> .<S> >> . >> . >> . >> . >> . >> . /o/ >> . >> . / / >> . >> . / / >> >> .<S> >> . >> . >> . >> . >> . >> . / / >> . o >> . / / >> . >> . / / >> >> .<S> >> . >> . >> . >> . >> . >> . / / >> . >> . o / >> . >> . / / >> >> .<S> >> . >> . >> . >> . >> . >> . / / >> . >> . / / >> . o >> . / / >> >> .<S> >> . >> . >> . >> . >> . >> . / / >> . >> . / / >> . >> . o/ / >> >>> If the telescope is aimed so that the photon is going straight down, >>> where is the sideways velocity of the photon? Why would filling the >>> telescope with water change the direction of the photon? There is none, and it wouldn't. This idea that a water filled telescope should change the direction of the light stems from rigid ether theory. If the light is a wave in an ether, and the ether is moving through the telescope, then the light should be 'dragged along with the ether' when its speed is reduced, and thus change its direction. (If this had been correct, you could measure the speed of the ether by measuring the angle.) But as we know, that is not observed. Fresnel tried to explain this apparent paradox with his ether drag theory. He assumed that the water to some extent drag the ether along with it, exactly enough to keep the light beam straight. >> >>> I understandaberrationnow. >> >> Evidently not, if you are still asking questions that someone who DID >> understandaberrationwould know the answers to > > I don't see any difference between a moving source and a moving > telescope, ie they are moving relatively to each other. Both Galilean > Relativity and SRT agree on this. I am not quite sure what you mean by this statement. The velocity of the source (star) has no effect on the direction in which we see the star, it is utterly irrelevant. This is very obvious when we observe the light from spectroscopic binaries. They may have a huge speed relative to each other, yet we always see them at the same spot, as one star. Remember that aberration is the phenomenon that the direction of light (or any velocity vector) is frame dependent. So aberration is _always_ between two relatively moving frames of reference (observers). If two observers are observing the same source, the aberration - that is the difference between the directions in which they see the source - depend _only_ on their relative speed. The speed of the source relative to them is irrelevant. Stellar aberration is the phenomenon that the direction in which we see a star changes throughout the year. That depends on the _change_ of the velocity of the Earth only. During half a year, this change is twice the orbital speed of the Earth, which is 3E4 m/s, or 10^-4 c. So the angle should be ~ v/c = 2*10^-4 rad = 41", which is what is observed. http://home.c2i.net/pb_andersen/pdf/aberration.pdf http://home.c2i.net/pb_andersen/pdf/Stellar_aberration.pdf -- Paul http://home.c2i.net/pb_andersen/ |