| Topic: |
Science > Physics |
| User: |
"" |
| Date: |
10 Oct 2005 01:32:45 PM |
| Object: |
Just a millimeter |
Will the light-spot of a light-beam or laser-beam of ten meters length
(may be sharpenend with a lens) move throughout half a year of
observation just a millimeter or not ?
The Bradley-aberration, discovered by Jean Picard 1680, is a movement
of the direction of light from the star gamma Draconis of
plus/minus 20 seconds of arc throughout half a year.
As this light is moving nearly parallel to the ecliptic axis, the
movement of it's direction is interpreted as a result of the movement
of the earth around the sun.
Will this work with a light source on earth too ? One can build a very
stable optical bank of ten meters in a direction, which once a day is
parallel to the axis of ecliptic ( practically once a day pointing to
gamma draconis).
Any results of such experiments and any interpretation would be
welcome.
Thanks
Hero
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| User: "Sam Wormley" |
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| Title: Re: Just a millimeter |
10 Oct 2005 02:28:57 PM |
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wrote:
Will the light-spot of a light-beam or laser-beam of ten meters length
(may be sharpenend with a lens) move throughout half a year of
observation just a millimeter or not ?
The Bradley-aberration, discovered by Jean Picard 1680, is a movement
of the direction of light from the star gamma Draconis of
plus/minus 20 seconds of arc throughout half a year.
As this light is moving nearly parallel to the ecliptic axis, the
movement of it's direction is interpreted as a result of the movement
of the earth around the sun.
Will this work with a light source on earth too ? One can build a very
stable optical bank of ten meters in a direction, which once a day is
parallel to the axis of ecliptic ( practically once a day pointing to
gamma draconis).
Stellar Aberration
http://scienceworld.wolfram.com/physics/StellarAberration.html
Europhys. Lett., 58 (4) , pp. 637-638 (2002)
Why the Bradley aberration cannot be used to measure absolute speeds. A comment
K. Kassner
Institut für Theoretische Physik, Otto-von-Guericke-Universität
Magdeburg Postfach 4120, D-39016 Magdeburg, Germany
(Received 3 September 2001; accepted 25 February 2002)
Abstract
In a recent article in this journal (SARDIN G., Europhys. Lett., 53 (2001) 310),
Sardin proposed to use the Bradley aberration of light for the construction of
a speedometer capable of measuring absolute speeds. The purpose of this comment
is to show that the device would not work.
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| User: "" |
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| Title: Re: Just a millimeter |
10 Oct 2005 02:53:42 PM |
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Sam Wormley wrote:
Hero.van.Jindelt@gmx.de wrote:
Will the light-spot of a light-beam or laser-beam of ten meters length
(may be sharpenend with a lens) move throughout half a year of
observation just a millimeter or not ?
The Bradley-aberration, ...
Stellar Aberration
http://scienceworld.wolfram.com/physics/StellarAberration.html
Europhys. Lett., 58 (4) , pp. 637-638 (2002)
Why the Bradley aberration cannot be used to measure absolute speeds. =
A comment
K. Kassner
Institut f=FCr Theoretische Physik, Otto-von-Guericke-Universit=E4t
Magdeburg Postfach 4120, D-39016 Magdeburg, Germany
(Received 3 September 2001; accepted 25 February 2002)
Abstract
In a recent article in this journal (SARDIN G., Europhys. Lett., 53 (2=
001) 310),
Sardin proposed to use the Bradley aberration of light for the constru=
ction of
a speedometer capable of measuring absolute speeds. The purpose of thi=
s comment
is to show that the device would not work.
Thanks, but i'm asking for something different.
Besides, with Bradley it is assumed one observes differences (!) of
directed speeds.
Hero
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| User: "" |
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| Title: Re: Just a millimeter |
11 Oct 2005 10:22:20 AM |
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wrote:
Sam Wormley wrote:
wrote:
Will the light-spot of a light-beam ... move...
You might think: just a millimeter on ten meters, that's not much? In
our world today we are depending a lot on high precision measurements,
so my question is a practical question in the first place.
Hero
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| User: "Sam Wormley" |
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| Title: Re: Just a millimeter |
11 Oct 2005 11:12:47 AM |
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wrote:
wrote:
Sam Wormley wrote:
wrote:
Will the light-spot of a light-beam ... move...
You might think: just a millimeter on ten meters, that's not much? In
our world today we are depending a lot on high precision measurements,
so my question is a practical question in the first place.
Hero
May I suggest you do a few stellar aberration calculation... which
should shed light (no pun intended) on your question.
2.5 Stellar Aberration
http://www.mathpages.com/rr/s2-05/2-05.htm
Stellar Aberration
http://scienceworld.wolfram.com/physics/StellarAberration.html
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| User: "" |
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| Title: Re: Just a millimeter |
11 Oct 2005 11:34:28 AM |
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Sam Wormley wrote:
Hero.van.Jindelt@gmx.de wrote:
Hero.van.Jindelt@gmx.de wrote:
Sam Wormley wrote:
Hero.van.Jindelt@gmx.de wrote:
Will the light-spot of a light-beam ... move...
May I suggest you do a few stellar aberration calculation... which
should shed light (no pun intended) on your question.
2.5 Stellar Aberration
http://www.mathpages.com/rr/s2-05/2-05.htm
Stellar Aberration
http://scienceworld.wolfram.com/physics/StellarAberration.html
What light should Your proposal throw on my question. Bradley and
others observed a difference of direction light from a star is comming
from. Now my experiment ( i hope it is done already ) proposes instead
of observing a light ray from a distant source, have a source of
lightrays on earth in an experiment with no moving parts, except for
the light. Just observe the position of the light-spot ten meters away
now and in half a years time.
Will there be a difference in position?
Or - if this experiment was done already - was there a differnec in
position ?
Any interpretation of results will be of interest too.
Hero
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| User: "Sam Wormley" |
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| Title: Re: Just a millimeter |
11 Oct 2005 11:43:43 AM |
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wrote:
Sam Wormley wrote:
May I suggest you do a few stellar aberration calculation... which
should shed light (no pun intended) on your question.
2.5 Stellar Aberration
http://www.mathpages.com/rr/s2-05/2-05.htm
Stellar Aberration
http://scienceworld.wolfram.com/physics/StellarAberration.html
What light should Your proposal throw on my question.
You won't know till you look.
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| User: "" |
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| Title: Re: Just a millimeter |
11 Oct 2005 11:56:28 AM |
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Sam Wormley wrote:
Hero.van.Jindelt@gmx.de wrote:
Sam Wormley wrote:
May I suggest you do a few stellar aberration calculation... which
should shed light (no pun intended) on your question.
2.5 Stellar Aberration
http://www.mathpages.com/rr/s2-05/2-05.htm
Stellar Aberration
http://scienceworld.wolfram.com/physics/StellarAberration.html
What light should Your proposal throw on my question.
You won't know till you look.
Thanks for Your patience with me.
I did look and other texts too. Nobody objects, that one can observe,
what Bradley observed, and this is still important for astronomy. There
are slightly different interpretations. So why not replace a stellar
source of light with one on earth and see, what happens?
Hero
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| User: "Sam Wormley" |
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| Title: Re: Just a millimeter |
11 Oct 2005 12:09:37 PM |
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wrote:
Sam Wormley wrote:
wrote:
Sam Wormley wrote:
May I suggest you do a few stellar aberration calculation... which
should shed light (no pun intended) on your question.
2.5 Stellar Aberration
http://www.mathpages.com/rr/s2-05/2-05.htm
Stellar Aberration
http://scienceworld.wolfram.com/physics/StellarAberration.html
What light should Your proposal throw on my question.
You won't know till you look.
Thanks for Your patience with me.
I did look and other texts too. Nobody objects, that one can observe,
what Bradley observed, and this is still important for astronomy. There
are slightly different interpretations. So why not replace a stellar
source of light with one on earth and see, what happens?
Hero
Why should there be any difference? Once light has left its
source and during the finite time of propagation the target
originally aligned with that source moves, aberration can
result.
Stellar Aberration
http://scienceworld.wolfram.com/physics/StellarAberration.html
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| User: "" |
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| Title: Re: Just a millimeter |
14 Oct 2005 02:37:18 PM |
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Hero.van.Jindelt@gmx.de wrote:
Sam Wormley wrote:
......
Whatever the outcome of my experiment, there's no explanation for it in
the theories of physics (otherwise please tell us!). So it's really
necessary to do this experiment. And - in the first place - for high
precision measurements it's important.
Although Sam couldn't answer my question, i'm really thankfull for his
postings. And the more i think about them, the more i'm convinced, that
there's a perl of physics in it. This should not go unnoticed into the
archives. So it deserves a thread on it's own:
" Movement in an independent frame of reference, which is made out of
light"
Hero
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| User: "" |
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| Title: Re: Just a millimeter |
11 Oct 2005 12:39:20 PM |
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Sam Wormley wrote:
Hero.van.Jindelt@gmx.de wrote:
.... So why not replace a stellar
source of light with one on earth and see, what happens?
Hero
Why should there be any difference? Once light has left its
source and during the finite time of propagation the target
originally aligned with that source moves, aberration can
result.
Stellar Aberration
http://scienceworld.wolfram.com/physics/StellarAberration.html
Sam , that's answering a question with a question.
So You formulate the reason, why i'm asking.
Is there an answer already ?
Hero
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| User: "" |
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| Title: Re: Just a millimeter |
12 Oct 2005 09:14:44 AM |
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wrote:
.... So why not replace a stellar
source of light with one on earth and see, what happens?
So i hope today there is someone on sci.physics, who knows the result
of such a simple experiment.
Thanks
Hero
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| User: "PD" |
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| Title: Re: Just a millimeter |
14 Oct 2005 02:51:45 PM |
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wrote:
Will the light-spot of a light-beam or laser-beam of ten meters length
(may be sharpenend with a lens) move throughout half a year of
observation just a millimeter or not ?
The Bradley-aberration, discovered by Jean Picard 1680, is a movement
of the direction of light from the star gamma Draconis of
plus/minus 20 seconds of arc throughout half a year.
As this light is moving nearly parallel to the ecliptic axis, the
movement of it's direction is interpreted as a result of the movement
of the earth around the sun.
Will this work with a light source on earth too ? One can build a very
stable optical bank of ten meters in a direction, which once a day is
parallel to the axis of ecliptic ( practically once a day pointing to
gamma draconis).
Any results of such experiments and any interpretation would be
welcome.
Thanks
Hero
Yes, it would work. Unfortunately, this would mean placing a telescope
on Gamma Draconis to observe the light coming from the Earth. This
might take more work than is worthwhile...
PD
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| User: "" |
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| Title: Re: Just a millimeter |
14 Oct 2005 03:01:21 PM |
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PD wrote:
Hero.van.Jindelt@gmx.de wrote:
Will the light-spot of a light-beam or laser-beam of ten meters length
(may be sharpenend with a lens) move throughout half a year of
observation just a millimeter or not ?
Yes, it would work. Unfortunately, this would mean placing a telescope
on Gamma Draconis to observe the light coming from the Earth. This
might take more work than is worthwhile...
This might be a funy experiment too. In the mean-time just turn the
source of light to the opposite side (revolution of half a circle),
remove the telescope, then You'll get, what i'm inquiring about: a
light source shining on a screen ten meters away.
Hero
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| User: "" |
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| Title: Re: Just a millimeter |
16 Oct 2005 10:02:04 AM |
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wrote:
Will the light-spot of a light-beam or laser-beam of ten meters length
(may be sharpenend with a lens) move throughout half a year of
observation just a millimeter or not ?
If this experiment is known to You, it would be very kind, to tell us
here about it. And for the rest, one might get unlocked from his/her
theories and take a look at it. Either we have to tell the astronomers
something about Bradley aberration or we have to add to precision
measurements and a new tone to our theories, so this experiment needs
Your promotion to be done.
Thanks
Hero
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| User: "" |
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| Title: Re: Just a millimeter |
16 Oct 2005 10:03:38 AM |
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wrote:
Will the light-spot of a light-beam or laser-beam of ten meters length
(may be sharpenend with a lens) move throughout half a year of
observation just a millimeter or not ?
If this experiment is known to You, it would be very kind, to tell us
here about it. And for the rest, one might get unlocked from his/her
theories and take a look at it. Either we have to tell the astronomers
something about Bradley aberration or we have to add to precision
measurements and a new tone to our theories, so this experiment needs
Your promotion to be done.
Thanks
Hero
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| User: "" |
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| Title: Re: Just a millimeter |
18 Oct 2005 05:31:28 AM |
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Hero.van.Jindelt@gmx.de wrote:
Will the light-spot of a light-beam or laser-beam of ten meters length
(may be sharpenend with a lens) move throughout half a year of
observation just a millimeter or not ?
Still waiting for answers is
Hero
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| User: "" |
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| Title: Re: Just a millimeter |
18 Oct 2005 05:53:58 AM |
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Either we have to tell the astronomers
something about Bradley aberration or we have to add to precision
measurements and a new tone to our theories,
****************
A flat?
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| User: "" |
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| Title: Re: Just a millimeter |
18 Oct 2005 03:28:44 PM |
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wrote:
Either we have to tell the astronomers
something about Bradley aberration or we have to add to precision
measurements and a new tone to our theories,
****************
A flat?
You must be moving too fast away from tunes, that are new to You, when
You hear them lower in frequency (with light this results in redshift).
Try moving at right angles.It's like advancing from mono to 5+1.
Hero
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| User: "JimboCat" |
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| Title: Re: Just a millimeter |
19 Oct 2005 02:51:55 PM |
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On 10 Oct 2005 11:32:45 -0700, wrote:
Will the light-spot of a light-beam or laser-beam of ten meters length
(may be sharpenend with a lens) move throughout half a year of
observation just a millimeter or not ?
The Bradley-aberration, discovered by Jean Picard 1680, is a movement
of the direction of light from the star gamma Draconis of
plus/minus 20 seconds of arc throughout half a year.
As this light is moving nearly parallel to the ecliptic axis, the
movement of it's direction is interpreted as a result of the movement
of the earth around the sun.
Will this work with a light source on earth too ? One can build a very
stable optical bank of ten meters in a direction, which once a day is
parallel to the axis of ecliptic ( practically once a day pointing to
gamma draconis).
Any results of such experiments and any interpretation would be
welcome.
I don't see any similarity between the two at all.
In the stellar aberration case, you have a distant point-source and a
highly-directional and focused detector: this arrangement can measure
the relative motion of source and detector.
In the other case you have a highly directional and focused light
source and a largely-isotropic detector with no relative motion between
them at all. This device cannot detect absolute motion, even if such a
thing existed. Interestingly, it *can* detect absolute acceleration,
but there are much more sensitive arrangements for doing this (google
"laser gyro").
Jim Deutch (JimboCat)
--
"AS THE HOLY BIBLE SAYS THERE ARE MORE THINGS IN HEAVEN THAN ON EARTH,
I AM SO GLAD WE CAN VISIT FAR LONG SPACE JOURNEYS AND I HOPE ONE DAY WE
DO FIND E.TS AND COMMUNICATE WITH THEM TO FIND OUT THERE KNOWLEDGE" -
schumigirl1956
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| User: "" |
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| Title: Re: Just a millimeter |
22 Oct 2005 08:22:27 AM |
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Hero wrote.
Will the light spot... move....
The bradley aberration...
That You replied, made me happy, Jim.
Jim worte:
don't see any similarity between the two at all.
The Bradlay aberration led me to this experiment and of course it's
different. The similarity is /should be, that in both cases the light
should come from the same direction, at a small angle with the axis of
the ecliptic - and the difference is then, starlight travelled a long
distance and the laserlight just a short one. And the outcome of the
experiment will show, if this makes a diference.
In the stellar aberration case, you have a distant point-source and a
highly-directional and focused detector: this arrangement can measure
the relative motion of source and detector.
In the other case you have a highly directional and focused light
source and a largely-isotropic detector with no relative motion between
them at all.
Of course, one can do the experiment with more similarity: observe with
a telescope gamma Draconis, close the hull around the telescope and set
a faint laserlight at the inside of the hull - so telescope - laser -
gamma Draconis are in one line. Wait for half a year, just observing. I
simplified this arrangement to a laser, may be a lens and a screen.
Interestingly, it *can* detect absolute acceleration,
but there are much more sensitive arrangements for doing this (google
"laser gyro").
My calculation is speed of light around 300 000 km/sec, speed of earth
rotating around the sun around 30 km/sec, that makes a millimeter on a
distance of ten meters, double to 20 meters will give You more.
Of course it's quite a lot of work to ensure there's no movement in the
parts and much more is to be considered.
In gyros change of angle /time counts, in our case twenty seconds of
one degree / six month, in Bradley aberration it's the ratio of two
speeds (to be more exact: the difference of the directed speed of
earth/ directed speed of light, at more or less a right angle to the
other directed speeds).
And so to the interpretation of Bradley aberration:
In the stellar aberration case, you have a distant point-source and a
highly-directional and focused detector: this arrangement can measure
the relative motion of source and detector.
In all theories it is stated, that Bradley aberration reflects the
movement of earth around sun. Ask Yourself, against which background,
relative to what ?
The movement of the source, may be it's already extinguished and what
movement, may be even years ago, of gamma Draconis is observed here?
And You can do it with every star shining from more or less the same
direction or from the opposite near the "celestial south pole of the
ecliptic". The result will always reflect earth's movement. Sam Wormley
wrote:
Once light has left its source and during the finite time of
propagation the target originally aligned with that source moves,
aberration can result.
He is taking the moving light and it's direction as a reference,
relative to what we are observing the movement of earth (if i'm not
misinterpretating).
This device cannot detect absolute motion, even if such a thing existed.
I hope, i never claimed that.
Interestingly, it *can* detect absolute acceleration, but there are much
more sensitive arrangements for doing this (google "laser gyro")
Is there "absolute acceleration" ? I'm not shure. I would say, with
Bradley aberration we can detect differences of directed speed /
velocity of earth. And may be with my experiment too.
Thanks Jim (Jimbo).
Sincerely Yours
Hero
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| User: "" |
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| Title: Re: Just a millimeter |
01 Nov 2005 03:53:16 PM |
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wrote:
Will the light spot... move....
The bradley aberration...
So, why is there not someone telling us, that this is interesting
experiment and promotes it, to get it done ?
Hero
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