Oh, dear me. Another blatant lie.
The contents of the following message speaks for itself:
http://groups.google.com/group/sci.physics.relativity/msg/d46bd31a0bf98518
On Oct 25, 4:45 pm, HW@....(Dr. Henri Wilson) wrote:
> On Wed, 24 Oct 2007 21:47:32 -0700, Jerry <Cephalobus_alie...@comcast.net>
> wrote:
> >On Oct 24, 4:14 pm, HW@....(Dr. Henri Wilson) wrote:
> >> On Wed, 24 Oct 2007 02:13:45 -0700, Jerry <Cephalobus_alie...@comcast.net>
> >> wrote:
> >> >On Oct 24, 3:10 am, George Dishman <geo...@briar.demon.co.uk> wrote:
> >> >> On 23 Oct, 22:32, HW@....(Clueless Henri Wilson) wrote:
> >> >> > Incidentally, this also tends to suggest that the fringe
> >> >> > production in a sagnac interferometer is something to do
> >> >> > with the phase relationship between INCOMING and OUTGOING
> >> >> > rays rather than the rejoining of the two oppositely moving
> >> >> > rays...I know that sounds impossible...but is it?
> >> >> Yes, for two reasons. The simpler is that if
> >> >> you look at the arrangement of the beam
> >> >> splitter, the remaining light goes back to
> >> >> the lamp but the more robust is that there
> >> >> would be a path length difference of nearly
> >> >> a metre (the loop length) between the originated
> >> >> light and that which has bone round the loop.
> >> >> That grossly exceeds the coherence length for
> >> >> a filament source so there is no way to form
> >> >> fringes with a detectable contrast ratio.
> >> >I think that you have gone -way- over Henri's head with
> >> >mention of coherence length.
> >> >To Henri:
> >> >Early experimentalists such as Michelson and Morley, Sagnac
> >> >etc. used monochromatic sources only during the alignment
> >> >stages while setting up their interferometers. Actual
> >> >experimental runs were always performed with white light.
> >> >The reason for this is that white light creates a distinctive
> >> >pattern of a central bright white fringe surrounded by a
> >> >rapidly fading set of colored fringes. The advantage of this
> >> >is that the central fringe of equal path length is always
> >> >readily identifiable, whereas monochromatic light produces
> >> >uniform fringes in which it is virtually impossible to
> >> >determine the central fringe of equal path length.
> >> >The distinctive pattern of fringes formed by white light
> >> >enabled Michelson and Morley, who recorded their observations
> >> >visually, not to "get lost" while figuring out how far their
> >> >fringes were displaced from their fiducial marks. In the
> >> >Michelson and Gale experiment, which was a giant Sagnac
> >> >setup, the central fringe, in the absence of rotation, would
> >> >appear precisely midway between the two images of the slit.
> >> >This enabled them to calibrate their apparatus for zero
> >> >rotational velocity; it was thus not necessary for them to
> >> >halt the rotation of the Earth to get a zero reading, which
> >> >would have been somewhat impractical in the absence of divine
> >> >intervention (Joshua 10:12-15).
> >> >Note that I stated that the pattern of colored fringes
> >> >surrounding the central bright fringe fades rapidly. This is
> >> >because the spacing between the red fringes and the blue
> >> >fringes is different. Within a few fringe widths from the
> >> >central fringe, the colored fringes overlap until the fringe
> >> >pattern is no longer perceptible. Since each fringe represents
> >> >a half wave difference in path length to the two images of the
> >> >source slit, this means that the path lengths must be
> >> >precisely matched, otherwise it would be impossible to see any
> >> >fringes at all.
> >> >This distance to which the path lengths must be matched,
> >> >otherwise fringes are invisible, is known as the "coherence
> >> >length". The coherence length for white light is no more
> >> >than a handful of microns. Your notion that "fringe
> >> >production in a sagnac interferometer is something to do with
> >> >the phase relationship between INCOMING and OUTGOING rays
> >> >rather than the rejoining of the two oppositely moving rays"
> >> >is totally ridiculous to anybody who knows anything at all
> >> >about optics.
> >> The sensible thing to do is use monochromatic light and tilt
> >> the top miror slightly in order to produce an 'optical wedge'
> >> effect. That produces a straight line fringe pattern rather
> >> than circles. Straight lines are easier to count than circles
> >> and in the case of gyros, make the direction of an acceleration
> >> easy to determine.
> >You have COMPLETELY lost the point. Earlier, you made the stupid
> >and asinine speculation that "fringe production in a sagnac
> >interferometer [has] something to do with the phase relationship
> >between INCOMING and OUTGOING rays rather than the rejoining of
> >the two oppositely moving rays."
> >George's point was that since white light Sagnac interferometers
> >are perfectly functional, your speculation is dead in the water.
> You didn't read properly. I SAID IT WAS IMPOSSIBLE.
Oh, dear me. Another blatant lie.
Henri, if you want to make such statements, hoping that
the previous history of our conversation would have
scrolled off people's newsreaders, you could at least
make the effort to trim the quote chain from this message,
or perhaps falsify the quote chain, which is another
technique which you have previously employed.
You wrote, as can be seen above in this same message,
> >> >> > Incidentally, this also tends to suggest that the fringe
> >> >> > production in a sagnac interferometer is something to do
> >> >> > with the phase relationship between INCOMING and OUTGOING
> >> >> > rays rather than the rejoining of the two oppositely moving
> >> >> > rays...I know that sounds impossible...but is it?
In other words, you did NOT state that it was impossible.
You were stating it as a possibility to consider, even if
it sounded unlikely.
Jerry