[LEAPSECS] Reliability

[Rob Seaman]

Tony Finch wrote:


> M. Warner Losh wrote:

>

>> Time used to be strongly coupled to the earth.

>

> Only because it was the most accurate clock we had. It might still  

> be the most reliable clock we have but our natural tendency to  

> optimisation means that isn't the most important consideration.


The high reliability of the Earth as a clock is an intriguing and  
original point.  Amazing we haven't long since run out of them!   
(Well, actually quite commonplace when the problem definition phase of  
a project is shorted.)


> Actually I would say that mean solar time was (past tense  

> deliberate) was a temporary aberration, lasting from mechanical  

> clocks replacing the sundial, to the rise of DST.


Mean solar time will outlast artificial clocks and the species that  
built them by a factor of something like 5,000,000,000 to 50,000.   
(Time remaining on the Earth clock compared to the Cro Magnon clock.)   
Mean solar time is an intrinsic characteristic of life on Earth, the  
count of our days.

The clock (singular deliberate) is a subdivision of the calendar.   
When the Sun goes nova and melts the crust of an Earth long void of  
humans and unrecognizable as ours due to plate tectonics (and lost in  
space due to the differential rotation of the Galaxy) - it will yet  
have been both theoretically and logistically possible to count every  
- single - unique - day that the long suffering, ever renewing globe  
has seen.

Our Moon will be more distant, its tides lessened.  The engine of  
plate tectonics will have halted, quieting seismic modes.  The Earth  
will be an even more reliable timekeeper at the end of days.  For all  
our sturm and drang, tidal slowing will have made no difference  
whatsoever to the countability of our days.

Days are real, not manufactured by the ITU.  Anything that attempts to  
mess with them is fated to fail - in the real world and perhaps even  
in the political world.  Leap seconds are a red herring.  A day  
without the Sun is devoid of meaning.

Atomic clocks are said to be better than solar timekeeping.  It's a  
funny definition that discounts a clock that lasts for 10 billion  
years and gets more accurate as it ages.

Beat that for optimization and natural tendencies :-)

Rob