[ntp:questions] Purpose of a leap second file?

unruh unruh at invalid.ca
Sun Mar 4 20:29:19 UTC 2012

On 2012-03-04, John Hasler <jhasler at newsguy.com> wrote:
> I wrote:
>> [UTC] localizes TAI to this particular planet.
> unruh writes:
>> That makes it sound as if TAI is some God given time.
> There being no god, nothing is god-given.
>> It is not. It was developed and defined in the context of precisely
>> this planet.
> It is based on universal physical constants rather then on the motion of
> a particular object.

It is based on this particular object. It is 1/86400 of the time from
mean noon to mean noon at a particular year (something like 1900). 
It has now been redefined in terms a certain atomic transition, ( a
highly peculiar and complex atom which just happened for a few years to
make the best clock-- it does not anymore.) As I said, the chances that
any other civilisation would have the same definition is 0. 

>> If there is a timekeeping species somewhere else in the universe, I
>> promise you they will NOT use TAI.
> They probably will use something similarly derived from physical
> constants.

It is not derived. It was a highly accidental, peculiar, process. Noone
could derive the value is in terms of fundamental constants. 

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