[LEAPSECS] Solar time: From mean solar days, to mean solar years

[Preben Nørager]

OMG its 290091200278565000. With THAT my proposal still stands :-)


2014-08-20 21:48 GMT+02:00 Keith Winstein <keithw at cs.stanford.edu>:

> Check that multiplication... :-)
>
> On Wed, Aug 20, 2014 at 2:42 PM, Preben Nørager <samp5087 at gmail.com>
> wrote:
> > I can not edit the numbers in my initial post, but I can do it here, and
> > with that my proposel still stands: Drop the leap second, and continue
> UTC
> > without leap
> > seconds, so that 1 mean solar year is defined as the
> > duration of 290091175979732 [31556925,9747x9192631770] periods of
> >
> > radiation in the caesium atom
> >
> >
> >
> > 2014-08-20 16:43 GMT+02:00 Keith Winstein <keithw at mit.edu>:
> >
> >> To be a pedant [but if you can't be one on the leapsecs mailing
> >> list...], the SI second is *9192631770* periods of the radiation etc.
> >> Your figure is high by 1000.
> >>
> >> On Wed, Aug 20, 2014 at 9:22 AM, Preben Nørager <samp5087 at gmail.com>
> >> wrote:
> >> >
> >> > In the discussion about whether or not to drop the leap second, I
> think
> >> > it
> >> > is not a question about solar time or not solar time. It is in other
> >> > words
> >> > not a question about either solar time or atomic time.
> >> >
> >> >
> >> >
> >> > If we drop the leap second it will be in favour of another timescale,
> >> > which
> >> > uses only atomic clocks to tell the time, but the time in that other
> >> > timescale will still be based upon a kind of solar time.
> >> >
> >> >
> >> >
> >> > About a hundred years ago it was decided, that the mean solar year,
> and
> >> > not
> >> > the mean solar day, should be the unit of international time.
> >> >
> >> >
> >> >
> >> > In 1960 the second was defined as 1/31556925,9747 of the mean solar
> >> > year,
> >> > and in 1967 the second was redefined [equally in length to the
> >> > previously
> >> > defined second] as the duration of 9192632770 periods of radiation.
> >> >
> >> >
> >> >
> >> > When the second was defined in 1960 it was defined as a fraction of
> the
> >> > so-called tropical year. That was a mistake of wording. The tropical
> >> > year is
> >> > a measurement of the solar longitude on the ecliptic, but the
> >> > international
> >> > definition of the second is not based upon measurement of the solar
> >> > longitude on the ecliptic.
> >> >
> >> >
> >> >
> >> > The definition of the second is based upon Newcomb's theory of the
> solar
> >> > system, and in that theory it is the barycenter of the solar system,
> and
> >> > not
> >> > the center of the sun, which defines the length of the solar year.
> >> >
> >> >
> >> >
> >> > The length of the solar year, according to Newcomb’s theory, is the
> time
> >> > for
> >> > the longitude of the barycenter of the solar system to increase 360
> >> > decrees.
> >> >
> >> >
> >> >
> >> > The solar year, thus defined, can be measured either for one year, or
> >> > for an
> >> > average of years.
> >> >
> >> >
> >> > But the 1960 and the 1967 definition of the second can also be used as
> >> > an
> >> > international definition of the mean solar year.
> >> >
> >> >
> >> >
> >> > I think we should drop the leap second, and continue UTC without leap
> >> > seconds as TI [International Time], so that 1 mean solar year is the
> >> > duration of 290091231835491000 [31556925,9747x9192632770] periods of
> >> > radiation in the caesium atom.
> >> >
> >> > _______________________________________________
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> >> >
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> >
> >
>
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