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    Re: no leap second coming in December
    From: Richard B. Langley
    Date: 2004 Jul 27, 14:19 -0300

    On Tue, 27 Jul 2004, Richard Langley wrote:
    
    >See 
    
    I should have been more specific:
    .
    
    -- Richard Langley
    
    and the PDF file
    >.
    >The length of the astronomical day varies because of several different
    >phenomena including tidal friction and the exchange of angular momentum
    >between the Earth's core, mantle, and atmosphere. During the past 100 years or
    >so, the length of day based on the Earth's rotation has almost always been
    >longer than a day containing exactly 86,400 seconds (the UTC day). The shorter
    >UTC day requires the periodic insertion of leap seconds, the last one at the
    >end of December 1998. Over the past few years, the Earth's average rate of
    >rotation has increased slightly and consequently the need for an additional
    >leap second has not yet been announced.
    >
    >-- Richard Langley
    >
    >On Tue, 27 Jul 2004, George Huxtable wrote:
    >
    >>On 24 July Paul Hirose wrote-
    >>
    >>>A few days ago the IERS announced there would be no leap second at the
    >>>end of this year. We will have a record-setting run of six
    >>>consecutive years with no leap second. The previous longest break was
    >>>1986 and 1987.
    >>>
    >>>At present UT1 is .46 second behind UTC. The offset is predicted to be
    >>>.49 second at the end of the year, and .52 second in mid-2005.
    >>
    >>Does this imply, then, that delta-T, the difference between universal time
    >>and ephemeris time, has remained "stuck" at a constant, or nearly-constant
    >>value, over that period of six years? If so, what vaue has it stuck at?
    >>
    >>And if so, does anyone understand the geophysical causes that have resulted
    >>in the slowing of the Earth's rotation, which has been so consistent over
    >>the last 80 years or so, to suddenly switch off, 6 years ago?
    >>
    >>Or have I misunderstood something completely?
    >>
    >>George.
    >>
    >>================================================================
    >>contact George Huxtable by email at george---.u-net.com, by phone at
    >>01865 820222 (from outside UK, +44 1865 820222), or by mail at 1 Sandy
    >>Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    >>================================================================
    >>
    >
    >
    >===============================================================================
    > Richard B. Langley                            E-mail: lang---.ca
    > Geodetic Research Laboratory                  Web: http://www.unb.ca/GGE/
    > Dept. of Geodesy and Geomatics Engineering    Phone:    +1 506 453-5142
    > University of New Brunswick                   Fax:      +1 506 453-4943
    > Fredericton, N.B., Canada  E3B 5A3
    >     Fredericton?  Where's that?  See: http://www.city.fredericton.nb.ca/
    >===============================================================================
    >
    
    
    ===============================================================================
     Richard B. Langley                            E-mail: lang---.ca
     Geodetic Research Laboratory                  Web: http://www.unb.ca/GGE/
     Dept. of Geodesy and Geomatics Engineering    Phone:    +1 506 453-5142
     University of New Brunswick                   Fax:      +1 506 453-4943
     Fredericton, N.B., Canada  E3B 5A3
         Fredericton?  Where's that?  See: http://www.city.fredericton.nb.ca/
    ===============================================================================
    
    
    

       
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