link to Home Page

Re: Preliminary Data Earth-Rotation-Experiment


In Article <9hmuuc$mig$1@news1.xs4all.nl> Josh worte:
> Thought it would be a good idea to post it already, before it can
> become undenyable evidence.

Apparently, for all the arguments AGAINST rotation slowing, saying
anything BUT leap seconds inserted every few decades, this is A KNOWN
SITUATION.  Here's some interesting info provided recently by a Troubled
Times member.  This is on the web, with charts
(http://www.zetatalk.com/theword/tworx385.htm), text quoted in part
below.

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

Professional astronomers know very well about the recent slowing of the
rotation of the Earth about its polar axis. ... Practical Astronomy with
your Calculator by Peter Duffett-Smith, Cambridge University Press,
Cambridge, 1988. ... chapter 16 describing the phenomenon of the recent
slowing of the Earth rotation in great details. The change of the Earth
rotation of in this book was calculated from the motion of the Moon for
old data (since 1620) or from the time measured by atomic clock (since
1984). For some unknown reasons the Earth rotation measured by the Moon
clock was accelerating from the year 1620 to the year 1680. Then the
Earth rotation was quite stable for more then two centuries. Suddenly,
since the year 1900 the Earth rotation began slowing quite rapidly, and
it is continuing slowing. In January 1986 the difference between ET
(ephemeris time) or TDT (terrestrial dynamic time) and UT (universal
time) was 54.87 seconds, UT being behind TDT; that is TDT-UT=Delta
T=54.87 seconds.

I found that International Earth Rotation Service gives a table showing
the Earth slowing data (Delta T) from January 1972 to January 2001
(monthly). In January 1, 2001 the slowing was 64.0908 seconds. The
International Earth Rotation Service also updates these data weekly.
Thus I was able to incorporate in this plot the slowing data including
June 1 of 2001. The data shown in the Figure coincide exactly with the
correspondent portion of the Figure 4 from the Peter Duffett-Smith's
book. The very recent data from the International Earth Rotation Service
show numbers which allow calculating Delta T for June 13, June 14, and
June 20 of 2001:

    June 13, 2001, Delta T = 64.208477 seconds
    June 14, 2001, Delta T = 64.208550 seconds
    June 20, 2001, Delta T= 64.209395 seconds

So, the change of Earth slowing during one day was 0.000073 second or 73
microseconds at that time; the change during one week was 0.000918
second or 918 microseconds. This very small daily change is very hard to
measure with common time devices. ... International Earth Rotation
Service web page .. data are based on very accurate measurements of the
Earth rotation using data from Very Long Baseline Interferometry (VLBI),
Satellite Laser Ranging (SLR), Global Positioning System (GPS)
satellites, and Lunar Laser Ranging (LLR). Data are supplied by many
organizations including U.S. Naval Observatory, Paris Observatory,
Institute of Applied Astronomy, St. Petersburg, and many other.
Astronomical times are fully
defined.

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@