Seeking a correct explanation for Stellar Abberation
in [Relativity]
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From: GogoJF on 6 Apr 2010 14:53 On Mar 6, 7:19 pm, train <gehan.ameresek...(a)gmail.com> wrote: > According to the special theory of relativity, the aberration only > depends on the relative velocity v between the observer and the light > from the star. > > http://www.mathpages.com/rr/s2-05/2-05.htm > > "relative velocity v between the observer and the light from the > star." > > Whic is always c , right? Looked on Wiki about "Aberration of light"- and printed it out in 12 pages. On page 3, it talks of "apparent and true positions". It uses the well known diagram illustrating stellar aberration. Along with the diagram, it supposes that the star is sufficiently distant, so that all light from the star travels in parallel paths to the Earth observer, regardless of where the Earth is in its orbit. And this is where the problem starts: Wiki: On the left side of figure 1, the case of infinite light speed is shown. S represents the spot where the star light enters the telescope, and E the position of the eye piece. Gogo: Then wiki very subtly poses this question: Wiki: If light moves instantaneously, the telescope does not move, and the true direction of the star relative to the observer can be found by following the line ES. However, if light travels at finite speed, the Earth, and therefore the eye piece of the telescope, moves from E to E' during the time it takes light to travel from S to E. Consequently, the star will no longer appear in the center of the eye piece. The telescope must therefore be adjusted. Gogo: But the truth of the matter, there is no adjusting- there is nothing that happens or exists which would suggest that any observable or instrumental change has been performed, other than by idea, belief, or faith that it was and is done this way. Aberration of light is a purely man-made concept! Wiki: Consequently, the star will no longer appear in the center of the eye piece. Gogo: This is complete baloney. This is pure theory- science fiction. In practice, this does not accur. Wiki: The telescope must therefore be adjusted. Gogo: Again, there is no adjusting going on here. This happens only "what if" light was finite. Wiki: When the telescope is at position E it must be oriented toward S' so that the star light enters the telescope at spot S'. Gogo: Spot S', do you see how ridiculous this sounds, logically? Again, this is 100% one way or 100% the other. Either light is instant, or it is finite. This illustration or principle is all or nothing. There is no step by step transformation process which starts from instant and transforms to finite. Wiki: Now the star light will travel along the line S'E' (parallel to SE) and reach E' exactly when the moving eye piece also reaches E'. Gogo: Again, this is describing a physical process which does not exist. It begins with instantaneous light and extrapolates from this reality to the reality of finite light. Do you see the major logical flaw here? Either light is instant, or finite. One of these realities cannot exist. Wiki: Since the telescope has been adjusted by the angle SES', the star's apparent position is hence displaced by the same angle. Gogo: This is simply not the case. There has been no adjustment of the telescope. Since I believe that light is instantaneous, the displacement of the star's apparent position by the angle SES' must be given a new interpretation and meaning.
From: GogoJF on 6 Apr 2010 18:23 On Apr 6, 1:53 pm, GogoJF <jfgog...(a)yahoo.com> wrote: > On Mar 6, 7:19 pm, train <gehan.ameresek...(a)gmail.com> wrote: > > > According to the special theory of relativity, the aberration only > > depends on the relative velocity v between the observer and the light > > from the star. > > >http://www.mathpages.com/rr/s2-05/2-05.htm > > > "relative velocity v between the observer and the light from the > > star." > > > Whic is always c , right? > > Looked on Wiki about "Aberration of light"- and printed it out in 12 > pages. On page 3, it talks of "apparent and true positions". It uses > the well known diagram illustrating stellar aberration. Along with > the diagram, it supposes that the star is sufficiently distant, so > that all light from the star travels in parallel paths to the Earth > observer, regardless of where the Earth is in its orbit. > > And this is where the problem starts: > > Wiki: On the left side of figure 1, the case of infinite light speed > is shown. S represents the spot where the star light enters the > telescope, and E the position of the eye piece. > > Gogo: Then wiki very subtly poses this question: > > Wiki: If light moves instantaneously, the telescope does not move, > and the true direction of the star relative to the observer can be > found by following the line ES. However, if light travels at finite > speed, the Earth, and therefore the eye piece of the telescope, moves > from E to E' during the time it takes light to travel from S to E. > Consequently, the star will no longer appear in the center of the eye > piece. The telescope must therefore be adjusted. > > Gogo: But the truth of the matter, there is no adjusting- there is > nothing that happens or exists which would suggest that any observable > or instrumental change has been performed, other than by idea, belief, > or faith that it was and is done this way. Aberration of light is a > purely man-made concept! > > Wiki: Consequently, the star will no longer appear in the center of > the eye piece. > > Gogo: This is complete baloney. This is pure theory- science > fiction. In practice, this does not accur. > > Wiki: The telescope must therefore be adjusted. > > Gogo: Again, there is no adjusting going on here. This happens only > "what if" light was finite. > > Wiki: When the telescope is at position E it must be oriented toward > S' so that the star light enters the telescope at spot S'. > > Gogo: Spot S', do you see how ridiculous this sounds, logically? > Again, this is 100% one way or 100% the other. Either light is > instant, or it is finite. This illustration or principle is all or > nothing. There is no step by step transformation process which starts > from instant and transforms to finite. > > Wiki: Now the star light will travel along the line S'E' (parallel to > SE) and reach E' exactly when the moving eye piece also reaches E'. > > Gogo: Again, this is describing a physical process which does not > exist. It begins with instantaneous light and extrapolates from this > reality to the reality of finite light. Do you see the major logical > flaw here? Either light is instant, or finite. One of these > realities cannot exist. > > Wiki: Since the telescope has been adjusted by the angle SES', the > star's apparent position is hence displaced by the same angle. > > Gogo: This is simply not the case. There has been no adjustment of > the telescope. Since I believe that light is instantaneous, the > displacement of the star's apparent position by the angle SES' must be > given a new interpretation and meaning. Apparent and true positions are the same thing- just different concepts, instant or finite, given to a single phenomenal event.
From: GogoJF on 6 Apr 2010 19:11 On Apr 6, 5:23 pm, GogoJF <jfgog...(a)yahoo.com> wrote: > On Apr 6, 1:53 pm, GogoJF <jfgog...(a)yahoo.com> wrote: > > > > > On Mar 6, 7:19 pm, train <gehan.ameresek...(a)gmail.com> wrote: > > > > According to the special theory of relativity, the aberration only > > > depends on the relative velocity v between the observer and the light > > > from the star. > > > >http://www.mathpages.com/rr/s2-05/2-05.htm > > > > "relative velocity v between the observer and the light from the > > > star." > > > > Whic is always c , right? > > > Looked on Wiki about "Aberration of light"- and printed it out in 12 > > pages. On page 3, it talks of "apparent and true positions". It uses > > the well known diagram illustrating stellar aberration. Along with > > the diagram, it supposes that the star is sufficiently distant, so > > that all light from the star travels in parallel paths to the Earth > > observer, regardless of where the Earth is in its orbit. > > > And this is where the problem starts: > > > Wiki: On the left side of figure 1, the case of infinite light speed > > is shown. S represents the spot where the star light enters the > > telescope, and E the position of the eye piece. > > > Gogo: Then wiki very subtly poses this question: > > > Wiki: If light moves instantaneously, the telescope does not move, > > and the true direction of the star relative to the observer can be > > found by following the line ES. However, if light travels at finite > > speed, the Earth, and therefore the eye piece of the telescope, moves > > from E to E' during the time it takes light to travel from S to E. > > Consequently, the star will no longer appear in the center of the eye > > piece. The telescope must therefore be adjusted. > > > Gogo: But the truth of the matter, there is no adjusting- there is > > nothing that happens or exists which would suggest that any observable > > or instrumental change has been performed, other than by idea, belief, > > or faith that it was and is done this way. Aberration of light is a > > purely man-made concept! > > > Wiki: Consequently, the star will no longer appear in the center of > > the eye piece. > > > Gogo: This is complete baloney. This is pure theory- science > > fiction. In practice, this does not accur. > > > Wiki: The telescope must therefore be adjusted. > > > Gogo: Again, there is no adjusting going on here. This happens only > > "what if" light was finite. > > > Wiki: When the telescope is at position E it must be oriented toward > > S' so that the star light enters the telescope at spot S'. > > > Gogo: Spot S', do you see how ridiculous this sounds, logically? > > Again, this is 100% one way or 100% the other. Either light is > > instant, or it is finite. This illustration or principle is all or > > nothing. There is no step by step transformation process which starts > > from instant and transforms to finite. > > > Wiki: Now the star light will travel along the line S'E' (parallel to > > SE) and reach E' exactly when the moving eye piece also reaches E'. > > > Gogo: Again, this is describing a physical process which does not > > exist. It begins with instantaneous light and extrapolates from this > > reality to the reality of finite light. Do you see the major logical > > flaw here? Either light is instant, or finite. One of these > > realities cannot exist. > > > Wiki: Since the telescope has been adjusted by the angle SES', the > > star's apparent position is hence displaced by the same angle. > > > Gogo: This is simply not the case. There has been no adjustment of > > the telescope. Since I believe that light is instantaneous, the > > displacement of the star's apparent position by the angle SES' must be > > given a new interpretation and meaning. > > Apparent and true positions are the same thing- just different > concepts, instant or finite, given to a single phenomenal event. Aberration of light doesn't exist, at least, not in the terms of the previous posts.
From: Dono. on 6 Apr 2010 21:56 On Apr 6, 4:11 pm, BozoJF <jfgog...(a)yahoo.com> wrote: > snip <
From: Paul B. Andersen on 8 Apr 2010 08:32
Don't snip the attributes if you don't snip the text! On 06.04.2010 23:55, Henry Wilson DSc wrote: > On Tue, 06 Apr 2010 20:36:59 +0200, "Paul B. Andersen"<someone(a)somewhere.no> > wrote: > >> Henry Wilson wrote: >> >>> Paul, the star in my question is always at rest wrt Earth. Therefore, even >>> though it appears as a distant point source like any other star, why should >>> aberration occur. >>> >>> I repeat::::: IT IS ALWAYS AT REST WRT EARTH. WHY SHOULD ABERRATION OCCUR? >> >> Quite. >> You keep repeating the same stupid question and thus confirming that you >> are not able to read the answer and that you don't understand >> stellar aberration. >> > I will simplify the question. > > Since the star is always at rest wrt planet Earth and exact integral number of > LYs away, why should I have to continually rotate my telescope to keep it in > the centre of view? _Because you constantly are changing your velocity_! Think just a little bit, Ralph. The orbital motion of your star will cause the direction to the star to change by 0.062 arcsecs. But _your_ change of _your_ velocity will cause the apparent direction to the star to change by 41 arcsecs. How do you think yhe former can compensate for the latter? > > SURELY YOU CAN UNDERSTAND THAT. If something isn't moving wrt you, do you have > to wobble your eyes to see it. Surely I understand that you again and again and again demonstrate that you do not understand stellar aberration! So I will repeat the answer to your question which has been quoted in the last umpteen postings, but considering your reading comprehension problems I will give a few supplementary comments: | 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. This means that if two stars are moving in opposite directions, and passing each other, you will see them at the same spot. The different velocities of the stars will not make them appear to be in different direction. In this particular case, if you are stationary in an inertial frame (like on the Sun), your orbiting star will annually appear to move along an ellipse with major axis 0.064 arcsecs. This is not aberration but proper motion. Hardly any terrestial (single) telescope can resolve this, so you would see it as a stationary star. In any case this proper motion is negligible compared to the 41 arcsecs aberration that you would observe from the Earth. | 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. This means that if two observers are moving relative to each other, and passing each other, they will see the star in different directions. THIS is aberration. It depends _only_ on the two observers relative velocity, the velocity of the star is irrelevant. The aberration angle (difference in the two directions) will be v/c radians, where v is the relative speed of the observers. | 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. Is it necessary to explain this? Stellar aberration is caused by the _change of the velocity_ of the _observer_. Nothing else! Read: http://home.c2i.net/pb_andersen/pdf/Stellar_aberration.pdf > > I know all about aberration. [..] > I know all about aberration. > > Now, please try to answer my very good and quite complex question. If you > cannot, please pass it to one of your brighter students.. Your stupidity have now ceased to amaze, so I won't be surprised if you yet again demonstrate that you still fail to understand stellar aberration. But I won't bother to try explain this yet another time. Case closed. -- Paul http://home.c2i.net/pb_andersen/ |