John and all:
REVISING Average Mean Atomic Year Value (Y2007):
According to <http://en.wikipedia.org/wiki/Tropical_year>: The current values
for Year and their annual change in the time of return to the cardinal ecliptic
points are: (1) vernal equinox: 365.24237404 + 0.00000010338×a days; (2)
northern solstice: 365.24162603 + 0.00000000650×a days; (3) autumn equinox:
365.24201767 − 0.00000023150×a days; and (4) southern solstice: 365.24274049 −
0.00000012446×a days, where a is number of years after Y2000. I consider the
YEAR length can be fixed at the Average Mean Atomic Year i.e. [365.24237404 +
365.24162603 + 365.24201767 + 365.24274049] / 4 =365.2421895575 days.
Astronomers, however, have fixed the Year value, Y2000 = 365.242189669781 days.
This during the past century, Y1900 was 365d 5h 48m 45s.9747 i.e.
365.24219878125 days”.
In my works http://www.brijvij.com/, I have aimed to get Mean Year value at:
(365+31/128) = 365.2421875 days, using div.4/skip 128th years (for Leap Days
count); or (7*128) =896-years/159 LWks to give Mean Year = (365+159/896) =
365.2421875 days =7*(52+1/6+29/2688). I now propose to fix, Y 2007 =
365.2421875 atomic-days and align with Y2000 = 365.242189669781 days, thus
*ratio 365.242189669781/ 365.2421875 =1.000000005940663686338260144168*. This
also, mean that ‘New Atomic Day =86400.00051327334 25 atomic second’; each
atomic second of 794243389646333 cycles of Cs-133 at hyperfine levels.
Accordingly, decimal second (sd)=1/240000th of atomic day =3309347457 periods
of radiations of Cs-133 at defined hyperfine levels. Regards,Brij Bhushan Vij
(MJD 2454360)/630+D-259 G (Sunday, 2007 September 16 H 19:09 (decimal) ISTAa
Nau Bhadra Kritvo Yantu Vishwatah -Rg Veda Jan:31; Feb:29; Mar:31; Apr:30;
May:31; Jun:30 Jul:30; Aug:31; Sep:30; Oct:31; Nov:30; Dec:30 (365th day of
Year is World Day) HOME PAGE: http://www.brijvij.com/******As per Kali
V-GRhymeCalendaar*****"Koi bhi cheshtha vayarth nahin hoti, purshaarth karne
mein hai"Contact # 011-9818775933 (M)001(201)962-3708(when in US)> From: [EMAIL
PROTECTED]> To: [email protected]> Subject: [USMA:39433] Re: Year> Date: Sun,
16 Sep 2007 03:13:17 -0700> > Also, http://en.wikipedia.org/wiki/Annum defines
the unit "annum", symbol > "a", with metric multiples kiloannum, megaannum,
gigaannum, etc. It states > that the symbol "yr" is deprecated.> --> John
Hynes> San Francisco> www.decimaltime.org> 2007 Sept. 16.425 UT> > -----
Original Message ----- > From: "John Hynes" <[EMAIL PROTECTED]>> To: "U.S.
Metric Association" <[email protected]>> Sent: Sunday, September 16, 2007 2:54
AM> Subject: [USMA:39432] Year> > > > Going back to the discussion on the
"year" unit, I found an interesting > > document called "The Unified Code for
Units of Measure" at > >
http://aurora.rg.iupui.edu/UCUM/ucum.html#section-introduction> >> > "Table 5:
Other units from ISO 1000, ISO 2955, and some from ANSI X3.50." > > includes:>
>> > name | kind of quantity | print | c/s | c/i | M | definition value | > >
definition unit> > tropical year | time | at | a_t | ANN_T | no | 365.24219 |
do> > mean Julian year | time | aj | a_j | ANN_J | no | 365.25 | do> > mean
Gregorian year | time | ag | a_g | ANN_G | no | 365.2425 | do> > year | time |
a | a | ANN | no | 1 | a_j> >> > "print" symbols include non-ASCII characters,
such as subscripts, while > > c/s and c/i are ASCII variants. M means "metric",
which these definitely > > are not. I think that someone here mentioned the
symbol "a" used with > > subscripts, so perhaps they were referring to a common
source. The > > following section is pertinent:> > ----------------> > ANSI
X3.50 had two different series of symbols for the units of time, the > > ones
from ISO 2955 as adopted by The Unified Code for Units of Measure and > > the
symbols "yr" "mo" "wk" "hr" and "sec" while "do" and "min" were > > defined
twice. The Unified Code for Units of Measure does not define these > > synonyms
of ISO 2955 symbols, but does adopt those units from ANSI X3.50 > > that are
not part of ISO 2955, namely "mo" and "wk" Month and week are > > useful units
mainly in business or clinical medicine.> >> > The semantics of the units of
time is difficult to capture. The > > difficulties start with the day: There is
the sidereal and the solar day > > that depend on the earth's rotation. The
earth's rotation is variable > > during one day and is continually slowing down
in the long run. The usual > > subdivisions of the day in 24 hours of 60
minutes and 60 seconds > > originated in Babylonia. The earth's rotation was
too inexact to measure > > time, which is why the 11th CGPM (1954) defined the
second based on a > > standarized historical tropical year (see below) which
was later (13th > > CGPM 1967-1968) replaced by frequency measurement. Thus the
second came to > > be the base unit of time and the day is now 864000 s exactly
with the > > Universal Coordinated Time (UTC) adding leap seconds every now and
then.> >> > For the year we have to distinguish the "tropical" (solar,
sidereal) year > > from the calendar year. And both are difficult. The tropical
year is the > > year defined by time the earth travels around the sun. This is
difficult > > to measure and varies over time. Around 1900 it was 365.242196
do, > > currently it is 365.242190 do and around 2100 it will be 365.242184 d.
In > > addition these durations are averages. The actual length of each year
may > > vary by several minutes due to the gravitational influence of other > >
planets. Thus there is quite a high uncertainty already in the fourth > >
decimal digit.> >> > The calendar year is also difficult because there is the
Julian calendar > > (Sosigenes of Alexandria and Julius Caesar, 45 BC) with a
slightly too > > long year of 365.25 do that causes the calendar to be one day
ahead of the > > tropical year in 128 years. The Gregorian calendar
(Christopher Clavius > > 1537-1612 and Pope Gregory XIII 1545-1563) leaves out
three leap years in > > 400 years (let n be the year number, the leap year is
dropped if n mod 100 > > = 0 but not n mod 400 = 0.) The Gregorian mean year is
thus 365.2425 do. > > This leap year arithmetic seems to be too much even for
astronomers, which > > is why the light year ends up being defined based on the
Julian year [NIST > > Sp. Pub. 811, 1995 Edition]. For this reason The Unified
Code for Units of > > Measure defines Tropical, Julian and Gregorian year by
means of > > subscripts, but assigns the default year symbol to the Julian
year.> >> > The week is 7 days, this is a biblic truth we can count on (it is
actually > > quite plausible that the week of seven days originated in
Babylonia and > > entered Jewish tradition during the Babylonian exile.)> >> >
The difficultiy continues with the month. The lunar (so called "synodal" > >
month is variable. Around 1900 it was 29.5305886 do currently it is > >
29.5305889 do and in 2100 it will be 29.5305891 do, which we fixate in the > >
5th decimal digit with a considerable uncertainty. The calendar month is > >
difficult because of the uneven distribution of days in a month over the > >
year, and because of the two different calendar years. But we will usually > >
use the mean calendar month, which is the Julian calendar year divided by > >
12.> >> > As a conclusion, great care has to be taken when the "customary
units" of > > time are used to measure time. The SI has fixated the second
which should > > be used whenever accuracy is required. For business purposes
the Julian > > calendar is sufficient especially since the notion of the
Work-Day (vs. > > Holiday) is more important than the imprecision over 128
years. [Sources: > > "Calendar" Britannica > >
Online.http://www.eb.com:180/cgi-bin/g?DocF=macro/5000/98/toc.html. Claus > >
Tondering, Frequently asked questions about calendars. Part 1. 1998. > >
http://www.pip.dknet.dk/~c-t/calendar.faq1.txt]> >> > -----------------> >> >
--> > John Hynes> > San Francisco> > www.decimaltime.org> > 2007 Sept. 16.410
UT> >> >> >> >> > >
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