[LEAPSECS] Reliability

[Rob Seaman]

Adi Stav wrote:


> what problems could exceeding the tolerance(s) cause?


Well covered in the archive.  For astronomy, 1 second of time is 15  
seconds of arc on the equator.  This is a large error (colossal for  
some purposes).  It doesn't appear that any other industry has  
actually performed a coherent risk analysis.  For some reason this is  
asserted to be the astronomers' responsibility.


> (Especially problems that time zones far from their reference  

> meridians, DST switches twice a year, and the difference between  

> mean and apparent solar time don't already cause).


This confuses periodic with secular effects, also in the archive.


> A good parallel would be adding leap hours and using the existing  

> DST mechanism



Reasons why leap hours won't work are in the archive.  There was a  
clear consensus from both sides of the aisle that the notion of leap  
hours is absurd.  Alternately, by relying on shifting timezones, there  
would be no underlying stabilized civil timescale permitting  
commonsense timekeeping inferences by humans.

By contrast, interval time is important to computers.  Computers are  
good at computing.


> I don't understand :)



Imagine a version of the Gregorian calendar that interpolates leap  
days only every 400 hundred years.  That would amount to about 3  
months at a time.  Since this is a whole season, it is equivalent to  
not stabilizing the calendar at all.

Leap hours or tweaking timezones can be interpreted the same way.  If  
intercalary adjustments are the width of a timezone, no practical  
stabilization is occurring.

Rob