[LEAPSECS] Schedule for success

[Rob Seaman]

The fact that the mean solar rate differs from the SI rate is the  
whole enchilada.  I have to put the Christmas lights on the tree, but  
you could search leapsecs for "secular" and "periodic" to locate my  
screed on this topic.

Rob
--

On Dec 22, 2008, at 11:43 AM, M. Warner Losh wrote:


> In message: <F0158734-CA0B-4CD1-BB0E-6B0AD31A1EB7 at noao.edu>

>            Rob Seaman <seaman at noao.edu> writes:

> : Tony Finch wrote:

> :

> : > On Mon, 22 Dec 2008, Rob Seaman wrote:

> : >>

> : >> 	No.  We have been using mean solar time formally since the 19th

> : >> century, and informally since we woke each morning to light  

> shining

> : >> through

> : >> the entrance of the cave.

> : >

> : > Apparent solar time is not mean solar time. Remember that for a  

> lot of

> : > history we used rubber hours that varied according to the time  

> between

> : > sunrise and sunset. Mean solar time cannot be established without

> : > reasonably accurate clocks.

> :

> : Either you haven't read this message yet:

> :

> : 	http://six.pairlist.net/pipermail/leapsecs/2008-December/ 

> 000714.html

> :

> : or I've yet again failed to make my point.

> :

> : Mother Earth "establishes" mean solar time simply by spinning on its

> : axis and orbiting the sun.  Apparent solar time is a mere  

> happenstance

> : of angles.  Rates matter more than offsets.

>

> But the second is no longer defined in terms of solar time, so why

> does this really matter?  UTC isn't the same as local time for most of

> the planet.  We already do time zones, and we already accept an hour

> or two of difference between our local time and the sun's time.  Why

> then the slavish need to keep UTC corresponding to the time at what is

> at best an arbitrary meridian?  The second no longer measures earth

> time.

>

> Warner