Re: Truly Offensive Bad Astronomy

oriel36 wrote:

The Equation of Time represents the only time leap seconds apply to
the axial cycle and then only as a principle to keep clocks in sync
with the axial cycle at 24 hours/360 degrees.You probably heard
something about this vaguely through Dava Sobel's book on Longitude -

Rather than have leap seconds due to the Equation of Time, we are
content to let our clocks on an annual basis go up to 15 minutes out
of sync with the sundial.

But we chose to base the length of the second on an average measure of
the 24 hour cycle over a period of years that ranged from 1750 to
1892, by comparing the solar cycle to the movements of the planets.
This was the basis, from the researches of Simon Newcomb, which led to
the scale of Ephemeris Time.

The tides require the expenditure of energy to lift up all that water
periodically. And so they lead to both the revolution of the Moon
around the Earth, and to the rotation of the Earth, slowing down -
because the Moon and the Earth are physical bodies, following the same
laws of motion as seen upon Earth.

So the day now is very slightly longer, adding up to about one second
a year, than it was about 180 years ago. But we must keep the length
of the second fixed, or we would lose the standard for the sizes of
our coils, resistors, and capacitors, among other things. There is no
pretentiousness in this; our measurements of things are genuinely able
to be this precise.

John Savard

.

Relevant Pages

  • Re: Kepler ,Newton and orbital geometry
    ... frame any time they need to. ... It is the actual time it takes the Earth ... clocks in sync with the axial cycle are lovely and easy to understand ... Huygens showing how clocks,the axial cycle and terrestrial longitudes ...
    (sci.astro.amateur)
  • Re: Before the nonsense breaks out
    ... in sync with the axial cycle at 24 hours/360 degrees without requiring ... you are under the Sun, it is noon; when the Sun is under your feet, it ... line between you and the center of the Earth on the ecliptic plane to ... get the real geometric angle involved, ...
    (sci.astro.amateur)
  • Re: Mars, September 25th 07
    ... Ya gotta understand something about Gherald. ... doubt it not but they would prove the revolutions of the Earth to be ... determined axial rotation via clocks,the closest them came was to ... elapses into the next 24 hour day and one axial cycle elapses into the ...
    (sci.astro.amateur)
  • Re: Einsteins Train Gedanken Re-visited
    ... the one moving with the earth would stay 'still' ... see we need to make it explicit) what do you claim about the clocks ... appropriate speed would keep it in sync. ... frame would then be inertial. ...
    (sci.physics.relativity)
  • Re: Einsteins Train Gedanken Re-visited
    ... the one moving with the earth would stay 'still' ... I thought the whole purpose of this exercise was to get clocks in sync ... frame would then be inertial. ...
    (sci.physics.relativity)
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