Re: Earth rotation

From: Oriel36 (geraldkelleher_at_hotmail.com)
Date: 07/02/04 

Date: 2 Jul 2004 10:06:10 -0700

"OG" <owen@gwynnefamily.org.uk> wrote in message news:<2keanvF1dqt2U1@uni-berlin.de>...
> "Oriel36" <geraldkelleher@hotmail.com> wrote in message
> news:273f8e06.0406260449.6c36d1cd@posting.google.com...
> >
> > My only enemy is laziness rather than anyone in particular.
>
> Don't be too hard on yourself, I don't think you're lazy ;-)
>
> >I will
> > freely bring up and discuss the analemmatic images you use to support
> > the false contention that constant axial rotation through 360 degrees
> > is 23 hours 56 min 04 sec by way of stellar circumpolar motion and
> > more importantly,you include axial tilt as a component in the Equation
> > of Time.
>
> Err, No I didn't. What I said was that
> "The vertical component of the analemma is a consequence of the axial tilt
> of the Earth, the lateral component (making it a figure of eight shape) is
> therepresentation of the Equation of Time (resulting from the elliptical
> orbit)."
> Clearly I separated the two components, either you misunderstood me or you
> misrepresent me. I'll be generous and assume the former.
>

> > You brought up the analemma and with only a single exception most of
> > the websites trade in the same falsehoods.
> >
> > http://www.longwoodgardens.org/Sundial/Analemma.html
> >
> > Of particular interest, in that the original use of the analemma only
> > refered to the lenght of shadow cast at noon as the Earth rotates to
> > face the Sun directly along its axial longitude coordinates,there is
> > no figure 8.
> >
> Well that's natural given the unequal length of the day. When "Noon" was
> defined as the sun crossing the meridian, then the only possible variable is
> the length of the shadow. As understanding and measurement improved to give
> the 'steady-time clock' of sidereal motion, the lateral component of the
> analemma (as expressed in the Equation of Time) could be identified.
>
> >
> > "Analemma in ancient writers denotes those sort of sun-dials which
> > shew only the height of the sun at noon, every day, by the largeness
> > of the shadow of the gnomon....If, then, analemma once referred to an
> > instrument which focused on the recording of noon time shadows, the
> > transition to an instrument which does the same under the "new"
> > definition of the time is an easy one to make."
>
> See above - the ancient writers were using the tools available to them. But
> they were unable to use tools that were NOT available to them.
>
>
> > You are bound to consider the motions of the Earth - axial and orbital
> > as two distinct and seperate motions.
> >
> > 1 - The Earth axial rotation and axial/equatorial orientation as a
> > distinct and seperate motion
> >
> > http://ottawa.rasc.ca/pictures/pdelorme/polaris.jpg
> >
> > That time lapse image taken against the Polaris star tells you that
> > axial and equatorial orientation remains constant throughout an annual
> > orbit.
>
> Two points
> 1- this isn't a time lapse image (in the normal meaning of the phrase)
> 2 - this shows nothing about orientation throughout the annual orbit as it
> is a single long exposure (c. 20 minutes by my reckoning). So I fail to see
> its relevance.
>
> >The 'Polaris' stellar circumpolar effect is an illusion
> > generated by the Earth's axial rotation and insofar as it is useful in
> > gauging constant axial/equatorial orientation,it should NOT be used as
> > an indicator for equatorial orientation to the Sun.
>
> Who exactly are you telling this to? And why?
>
> > Let's take a look at the analemma image -
> > http://www.wengersundial.com/Analemma/analemma.jpg
> >
> > You are assuming that the Earth's equatorial orientation to the Sun
> > changes but as already stated,equatorial orientation is a property of
> > the Earth axial orientation as an independent motion which remains
> > constant throughout its annual orbit.
>
> Hang on a minute - the Earth's equatorial orientation _to the Sun_ DOES
> change
> throughout the year. The axial orientation remains the same, but since the
> equator is inclined to the ecliptic, the equatorial orientation to the Sun
> is bound to change. How strange that you don't see this.
>

I understand that you did not think the whole thing through carefully
enough,not so much that I fault you for it is standard thinking for
the last 300 years but I assure you that Equatorial orientation as a
property of axial rotation is always tangential to axial orientation.

Who knows,you may even enjoy how the astronomers in the 17th and 18th
century were fallible on the axial and orbital motions of the
Earth,took a step backwards from heliocentricity to geocentricity and
assigned all axial and orbital effects to axial/equatorial
orientation to the Sun.

When things go wrong at such a fundamental level,investigation of
physical and celestial phenomena becomes pointless when it should be
the most vibrant area imaginable.

I am too busy to lament the failures of astronomers from a different
era much less contend with men who build concepts on these wrong
astronomical turns,it is a waste of a life as far as I'm concerned and
with each passing generation the intellectual atrophy becomes worse as
it spreads from one discipline to the next.Worst of all,children are
influenced by the intellectual pretension and the ability to render
insincerity in abtruse technical and mathematical wordplays and that
is unforgivable,how shallow it is to witness self-congratulation at
the expense of the wider population.Given half a chance,the wider
population enjoys the insights of the natural world but astronomy at
present remains out of bounds insofar as the spectacular images of
celestial objects is hijacked by men who place emphasis on the space
in between objects be they planets,stars or galaxies.

When men grow up and jettison the idea that 'space' has geometric
properties perhaps astronomy will recover but I suspect the recovery
will come from another discipline first and I have every reason to
believe that geology,climatology or another Earth science will move on
and not to pay homage to physics related concepts.Your idea that
somehow axial orientation is constant while equatorial orientation
changes would be typical for a contemporary physicist or
astronomer,it may change but that is entirely up to you.

 
> >The Earth does not tilt towards
> > and way from the Sun as an independent motion,what occurs is that the
> > Earth's ORBITAL orientation changes over the course of an annual
> > orbit.
>
> Don't be ridiculous, the orbital plane is constant. That doesn't change. How
> could it?
>
> >
> > Clearly stated,the Earth's orbital orientation causes the change in
> > seasons rather than any property of the Earth's axial tilt which
> > maintains constant orientation.
>
> A strange statement. The Earth's orbital orientation has to be in the plane
> of the ecliptic (by definition), since the orbit has to be the plane that
> cuts the Earth and Sun throughout the year. This does not change over the
> year. The effect of which you speak is due to the inclination between the
> constant plane of the orbit (which defines the ecliptic and hence the
> position of the Sun) and the constant axis of rotation (which defines the
> plane of the equator). The difference between the two planes gives rise to
> the change in seasons. You can't say that the effect is due to one plane
> rather than the other, since it is due to the angle between the two planes.
>
> > > > The Earth's axis remains orientated,over the course of an annual
> > > > orbit,to Polaris.
> > >
> > > Yup!
> > >
> > > > Now genius,figure this out.
> > > >
> > > > If axial orientation is constant and the Earth orbits the Sun,you
> > > > conclude that it is the change in the daylight/darkness line as a
> > > > property of the Earth's orbital orientation which causes the
> > > > hemispherical diiference in seasons (summer in Southern/winter in
> > > > northern and visa versa).
> > >
> > > or vice versa
> > >
> > > > The following graphic will not show you how the daylight/darkness line
> > > > as a property of orbital orientation shifts against the Earth's axis
> > > > (which remains constantly orientated to Polaris over an annual orbit)
> > > > but you will have to assume it.
> <links snipped>
> > > > You will notice that the daylight/darkness line as a property of
> > > > orbital orientation changes in accordance with Kepler's second law
> > > > subsequently it is this orbital motion of the Earth,assuming constant
> > > > axial rotation, that generates the natural unequal day.
> > >
> > > Agreed - so glad you agree that the sun-at-noon day is unequal
> > >
> >
> > A geometer phrases it as the rotational asymmetry due to constant
> > axial rotation moving through variable orbital motion.
>
> Yes, but do you agree that the sun-at-noon day IS unequal?
>
> > > > Axial tilt or equatorial orientation to the Sun changes the asymmetry
> > > > between daylight/darkness however it has absolutely no effect on the
> > > > total lenght of a day from noon to noon and the Equation of Time
> > > > equalises that variation from one rotation to the next.
> > >
> > > Agreed - the time between the noon and noon on consecutive days is
> nothing
> > > to do with axial inclination.
> > >
> >
> > Consecutive rotations to be precise,As axial orientation neither
> > accelerates or retards the return of axial longitude coordinates back
> > to the Sun/Earth line (noon),the variation can only be due to the
> > shift in the orbital orientation to the Sun/Earth line.
>
> You keep going on about the earth's axial orientation. This is irrelevant.
>
> > I have spoken of orbital orientation and thought it was clear enough
> > but apparently this looks mysterious to some when it clearly is not.
> >
> > The arrows in the following image reflect the seperate orbital motion
> > of the Earth and the division between equal amounts of daylight and
> > darkness as a property of the Earth's orbital orientation to the
> > Sun.The behavior of the shift in the division between
> > daylight/darkness throughout an annual orbit is in accordance with
> > Kepler's second law of planetary motion.
>
> > http://www.mhhe.com/physsci/astronomy/fix/student/images/04f15.jpg
> >
> > http://www.users.muohio.edu/primacag/images/earth%20from%20space.gif
> >
> > Even without knowing what caused the unequal lenght of a day as
> > measured by one axial rotation through 360 degrees wrt the Sun to the
> > next,our astronomical ancestors crafted the 24 hour/360 degree
> > longitude system to the assumption that axial rotation is constant via
> > the Equation of Time correction.
>
> Unless you have a constant clock, you don't know about the Equation of Time.
> The Sun does not provide a constant clock. Therefore the 'astronomical
> ancestors' did not have the EoT.
>
> >In the 21st century we can see that it
> > is not only the effect of constant axial rotation moving through
> > variable orbital motion,but how the orbital orientation changes in
> > accordance with Kepler'ssecond law.
> >
> > > > The analemma or basically what the geocentric motions of the Sun look
> > > > like from the perspective of a 24 hour clock is astronomical fraud
> > >
> > > What do you mean when you say it is a fraud?
> > >
> >
> > Ah,Flamsteed !.
> >
> > As axial rotation was already assumed to be constant by way of the 24
> > hour/360 degrees longitude equivalency and the Equation of Time
> > correction,Flamsteed creates a fraud by piggybacking on that existing
> > assumption and linking the Earth's rotation directly to stellar
> > circumpolar motion.
>
> Let me see, IIUY, you don't claim there is an equable solar clock. However,
> you do claim that if the uneven Solar clock is 'corrected' by the Equation
> of Time then there is a constant clock. Is this what you mean?
>
> If we can clarify this point then we can continue this thread.
>
> <rest of thread snipped, but I may return to it later>
>
> Just one little question though - did you do the experiment with Cartes de
> Ciel?

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