Re: Earth rotation

From: Craig Markwardt (craigmnet_at_REMOVEcow.physics.wisc.edu)
Date: 06/27/04 

Date: 27 Jun 2004 02:27:42 -0500

geraldkelleher@hotmail.com (Oriel36) writes:
> Craig Markwardt <craigmnet@REMOVEcow.physics.wisc.edu> wrote in message news:<onacyso7k4.fsf@cow.physics.wisc.edu>...
> > geraldkelleher@hotmail.com (Oriel36) writes:
> > > There is nothing difficult in any of this,the Equation of Time
> > > facilitates the seamless transition from one 24 hour day to the next
> > > 24 hour day,Monday in Tuesday ect ,by using the rotation of the Earth
> > > on its axis as a gauge and the Sun as a reference.
> > >
> > > Look ,no geocentricity !,no motion of the sun and stars and this alone
> > > indicates why you adopted an inferior proposal by Flamsteed.Here is
> > > what John Harrison thought of astronomers and I concur.
> >
> > You seem to be missing that the Equation of Time is not an abstract
> > entity which exists unto itself.
>
> The Equation of Time is the mathematical bridge between the natural
> unequal day and the 24 hour clock day.It keeps one 24 hour day rolling
> over to the next 24 hour day by making use of the noon determination
> as the Earth axially rotates to face the Sun directly.

In fact, the "Equation of Time," as it is commonly used today for
basic astronomical applications, is based on Newcomb's *Tables of the
Sun* (1895), which are in turn are based on observations of various
stars (1882) used to determine the sidereal reference time.

So, your claim that the Equation of Time is a "mathematical bridge,"
may be true in the sense that it involves mathematics. However it is
more true that the Equation of Time is an empirically determined
function, not a fundamental one. The "Equation of Time" would not
exist without observations of stars from the earth used to determine
sidereal time.

> The solar day and the
> > civil day are defined by humans naturally constrained to live on the
> > earth, and the Equation of Time is merely a means of translating
> > between the two time systems. Thus, your "look, no geocentricity!"
> > comment does not logically follow.
> >
> > CM
>
> You and your relativistic colleagues spent the last 100 years trying
...

Your derogatory reference to relativity is irrelevant. As I showed
above, the relevant theories and observations under discussion were
developed before the introduction of the first theory of relativity in
1905.

> The principles behind the 24 hour/360 degree equivalency for axial
> rotation was developed by brilliant people who assumed axial rotation
> to be constant and fixed the equivalency to the geometry and geography
> of the planet.They also knew that by using the Sun as a gauge for
> determining constant axial rotation that there was a variation from
> one complete axial rotation to the next.They equalised the variations
> over the course of an annual orbital cycle by adding or subtracting
> minutes and seconds to observed noon which reduces the variation to a
> constant 24 hour day.

Your claim is unsubstantiated. In fact, Newcomb and other astronomers
based their timekeeping on the stars, not the sun (Newcomb, 1882).

CM

References

Newcomb, S. 1882, Ast. Am. Eph, "Catalogue of 1098 Standard Clock and
  Zodiacal Stars," v. 1, pt. 4, pg. 147
Newcomb, S. 1895, Ast. Am. Eph, "Tables of the Motion of the Earth on
  its Axis and Around the Sun," v. 6, pt. 1, pg. 29

Relevant Pages

  • Re: non relativist / non aetherist reply
    ... > | the Earth axially rotates out of its orbital shadow) and you will ... > | the Sun. ... motion.You view the circumpolar motion of the stars in this light ... assumes axial rotation to be constant and equalises all the variables ...
    (sci.physics.relativity)
  • Re: Earth rotation
    ... > as the Earth axially rotates to face the Sun directly. ... Sun*, which are in turn are based on observations of various ... > rotation was developed by brilliant people who assumed axial rotation ... based their timekeeping on the stars, not the sun (Newcomb, 1882). ...
    (sci.geo.geology)
  • Re: what has happened to people
    ... The entire universe revolves around the sun once a year. ... the standard pace of that day was transfered to axial rotation as a 4 ... of the Copernican resolution for retrogrades by isolating the Earth's ... "For to the earth planetary motions appear sometimes direct, ...
    (sci.astro.amateur)
  • Re: RA question
    ... But the Earth also revolves around the Sun. ... Honor Copernicus by not mentioning his name. ... Clocks are kept in sync with axial rotation as a principle,as ...
    (sci.astro.amateur)
  • Why be a believer?
    ... > SECOND the Universe is incomprehensible in size and by comparison our World ... > Sun, Stars and Planets revolved around the Earth. ... > Acoran [Supreme] ...
    (alt.religion.christian)
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