[tz] What's "right"?

[John Sauter]

On Sat, 2020-11-14 at 20:23 +0000, Michael H Deckers via tz wrote:
>      This year, at the instant when UTC was 2020-03-08T10Z,
>      Pacific time jumped from 2010-03-08T02 to 2010-03-08T03,
>      and when UTC was 2017-01-01T00Z, TAI jumped from
>      2017-01-01T00:00:36 to 2017-01-01T00:00:37, as the IERS
>      tells us. Since the rates of UTC, Pacific time and TAI
>      are the same, the question, what was UTC when Pacific time
>      was 2010-03-08T02:30, is exactly similar to the question
>      what was UTC when TAI was 2017-01-01T00:00:36.5.
> 
>      Michael Deckers.
> 

Since 2017-01-01T00:00:36.5 TAI is a valid time, and UTC has a name for
every second, there must be a corresponding UTC time.  If I have done
my arithmetic correctly, that time is 2016-12-31T23:59:60.5 UTC.

This is not the same as asking for the UTC corresponding to 2010-03-
08T02:30 Pacific time, because that is not a valid time.  That is,
there is no point in time with that name.
    John Sauter (John_Sauter at systemeyescomputerstore.com)
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