[geocentrism] Re: Challenge
- From: Alan Griffin <ajg@xxxxxxxxxxxxx>
- To: geocentrism@xxxxxxxxxxxxx
- Date: Mon, 09 Aug 2004 18:31:32 +0100
On 08 Aug, Philip <joyphil@xxxxxxxxxxx> wrote:
> Friends I need to have your opinion on my analysis and answer to Alan. I
> can't really believe it was so simple. I might be missing something. For
> simplicity I have ignored that there are both annual and diurnal effects
> to be considerd.
> Alan you said the following.
> I saw my brother this evening. He says that the aberration of light
> proves that the earth moves.
> If the earth were stationary and the stars moving round it, their
> angular velocities would all be the same, but their linear velocities
> would be different, because of their different distances. This would
> mean that the aberration of light would be different for different
> stars, depending on their distance.
> I need hardly tell you, that the aberration of light is the same for all
> stars!
> Alan Griffin
> Thank you Alan for that information. I hope it is correct that the
> aberration is the same for all stars. I have taken so long to respond
> because as I said the internet presented too much confusion over this
> aberration. I should have gone to my ancient physics book in the
> beginning.
> So now I know what aberration is. I thank you for informing us that the
> observed aberration is the same for all stars irrespective of their
> distance from us.
> I believe that to be true. But you are wrong in taking this to prove the
> earth moves. It took a bit of playing with the sugar and salt containers
> on the table for me to visualise it.
> First lets put the reality of aberration up front. This is not to teach
> my learned superiors, but to give them every opportunity to show me my
> errors if I get it wrong. This geocentric stuff is a new learning curve
> for me and calculus I don't want to know about.
> Take a right angle triangle A B the base, and B C the vertical at right
> angles to AB. BC is looking at star S. AC is the angle of observation of
> S' after the observer has moved from from B to A. BCA is the angle of
> aberration. It seems to me here that this angle would occur whether the
> star moved, or the observer. But that is irrelevant for the moment.
> In practical terms, Aberration according to my book is the angle one has
> to shift his gaze (the angle of the telescope) to keep looking at the
> particular star as he moves at right angles to the it. Looking straight
> out vertically at a star as we the observer moves forward we have to
> look back.
> Oh dear. I've done that in the train. Hasn't everyone? Notice something?
> All those telegraph poles close by have a much greater aberration than
> the distant mountains. Thats when I am moving.
Oh dear indeed! I'm afraid you need to up the scale of your
experiment a bit! The stars are much further away than your salt cellar.
Your simple triangle does not work, merely because the light from all the
stars is parallel when it hits the earth.
If you were right, you would go out and look at the night sky, and
look at the pole star. It would be at a certain angle, and would be in the
North. Now travel 100 miles west and look at the pole star again.
According to you, it would no longer be north because you'd have moved,
but in fact the rays are parallel to the original ones, so it would still
be north.
> Am I getting something wrong here. Ok so the distant stars are really
> distant compared to Proxima. So if I am moving, then the angle of
> aberration would be greater for proxima (the telegraph pole) than the
> rim stars, (the distant mountains) Do it with three salt shakers, one
> being the moving observer.
Yes, you're getting something wrong. Aberration is the parallel
light appearing to come from a different direction because we're moving.
The umbrella and the rain is an excellent analogy. Do you not understand
it?
> But Alan said with absolute certainty that the aberration for all the
> stars is the same. So we cant be moving after all. Either that or all
> the stars are the same distance away. (have we heard that before?)
> So back to the other proposition. The stars move around the stationary
> earth.
> I used a gramaphone turntable. With the observer sitting on the shaft
> stationary in the centre. I put Proxima half way out and the salt cellar
> on the edge and spun the turntable. What do you know. The angle of
> aberration was the same for both stars. In fact I had to put Proxima on
> a slightly different radian to the other star or I would never be able
> to see it.
Again, the stars are giving out parallel light. If they move they
will produce aberration, but the amount of aberration depends on their
speed, not the angular velocity. If they travel at different speeds, they
will produce different angles of aberration.
> I don't know Alan, but perhaps your brother will have to come up with
> something better to prove it is the earth and not the stars moving.
No I don't think so. Physics still rules O.K.!
Alan
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