What now, Dr. Moebius?
Prepare your minds for a new scale...
of physical scientific values, gentlemen.
Mark Calabretta takes the lazy man's way out and appeals to facts:
> Here in a topology-free way is what the axis labels of my graph look
> like during the said leap second insertion:
>
> UTC axis TAI axis DTAI
> 2005/12/31 23:59:58 2006/01/01 00:00:30 32
> 2005/12/31 23:59:59 2006/01/01 00:00:31 32
> 2005/12/31 23:59:60 2006/01/01 00:00:32 32
> 60.9 32.9 32
> 60.99 32.99 32
> 60.999... 32.999... 32
> 2006/01/01 00:00:00 2006/01/01 00:00:33 33
> 2006/01/01 00:00:01 2006/01/01 00:00:34 33
>
> The seconds keep step and the graph has no gaps, jumps or kinks.
Now let's look at a leap hour introduced as an extra "fall back" hour:
UTC TAI
2600-12-31T23:59:58 2601-01-01T00:00:31 33
2600-12-31T23:59:59 2601-01-01T00:00:32 33
2600-12-31T23:00:00 2601-01-01T00:00:33 33
2600-12-31T23:00:01 2601-01-01T00:00:34 33 (?)
... ...
2600-12-31T23:59:58 2601-01-01T01:00:31 33 (?)
2600-12-31T23:59:59 2601-01-01T01:00:32 33 (?)
2601-01-01T00:00:00 2601-01-01T01:00:33 3633
I chose to introduce the leap hour on December 31 - I don't believe
the proposal indicates the date for doing so. Folks have been
tossing around the notion of aligning this with daylight saving time
- but DST in what locality? Does anyone really believe that a leap
hour would be introduced on different calendar dates worldwide? (It
seems to me that the one time it is guaranteed NOT to occur is during
a daylight saving transition.)
Not satisfied with the ITU position that UTC should merely be
emasculated to correspond to TAI - 33s - Nx3600s (which, of course,
really has the effect of ensuring that TAI itself will remain a
completely irrelevant mystery to the public), some would completely
eliminate UTC from the equation (or is it that they would eliminate
TAI?) Something like:
GMT TAI
2600-12-31T23:59:58 2601-01-01T00:00:31
2600-12-31T23:59:59 2601-01-01T00:00:32
2600-12-31T23:00:00 2601-01-01T00:00:33
2600-12-31T23:00:01 2601-01-01T00:00:34
... ...
2600-12-31T23:59:58 2601-01-01T01:00:31
2600-12-31T23:59:59 2601-01-01T01:00:32
2601-01-01T00:00:00 2601-01-01T01:00:33
But we're to believe that this would be implemented as an omitted
"spring forward" hour - ignoring the fact that many localities don't
currently have this option because they don't use DST at all - can't
omit what you don't have in the first place. Well - fine, a "spring
forward" event might look like:
GMT TAI
2600-12-31T23:59:58 2601-01-01T00:00:31
2600-12-31T23:59:59 2601-01-01T00:00:32
2601-01-01T01:00:00 2601-01-01T00:00:33
2601-01-01T01:00:01 2601-01-01T00:00:34
2601-01-01T01:00:02 2601-01-01T00:00:35
But under this interpretation we're to believe that the very notion
of international civil time is anathema (except perhaps for TAI with
some oddball persistent 33s offset and either a one hour gap or one
hour repetition every few hundred years). What this means is that
*local* civil/business/legal time contains this gap or this
repetition. I suspect we can agree that the civilians/
businesspersons/lawyers won't care whether the issue is local or not,
all they are going to see is a repeated time sequence or a gap - and
with no possibility of appeal to standard time, because standard time
as we know it simply won't exist anymore.
And historical time? Well, historians will simply have to get with
the program. Suck it up. Perhaps loudspeakers will announce the
arrival of the leap hour (or leap timezone migration event) with the
admonition to refrain from historically significant activity for the
space of one hour. (This announcement would be unnecessary in the
Washington, D.C. city limits, of course.)
And more to the point, since international time is a fiction, this
gap/overlap in civil/business/legal/historical time would occur twice
a year, every year. Perhaps it could be scheduled to coincide with
the State of the Union Address to minimize its historical impact.
I suppose this would be a good way to finally convince folks to do
away with DST.
But, of course, one suspects that even the ardent supporters of the
"timezone" proposal don't really expect it to be adopted. The ITU
has made it pretty clear that only two options are on the table - the
status quo of leap seconds, or the perceived-to-be-politically-
expedient, albeit goofy, proposal of leap hours. As I said in an
earlier message (and as Mark has now so clearly delineated), the only
viable way to introduce a leap hour is just like a leap second, as
additional ticks added to the clock:
UTC TAI
2600-12-31T23:59:58 2601-01-01T00:00:31 33
2600-12-31T23:59:59 2601-01-01T00:00:32 33
2600-12-31T24:00:00 2601-01-01T00:00:33 33
2600-12-31T24:00:01 2601-01-01T00:00:34 34
2600-12-31T24:00:02 2601-01-01T00:00:35 35
... ...
2600-12-31T24:59:58 2601-01-01T01:00:31 3631
2600-12-31T24:59:59 2601-01-01T01:00:32 3632
2601-01-01T00:00:00 2601-01-01T01:00:33 3633
2601-01-01T00:00:01 2601-01-01T01:00:34 3633
2601-01-01T00:00:02 2601-01-01T01:00:35 3633
As Mark says: "The seconds keep step and the graph has no gaps,
jumps or kinks." (Well, some might argue that this whole idea is
kind of kinky.)
I'm only speculating about the behavior represented above for DUT1
(or DTAI or whatever) during the progress of the leap hour, of course
- of course, because the "proposal" doesn't choose to contemplate
such distressing issues. Ooooh! It makes their widdle heads hurt!
BTW - thanks to whoever for reminding me of the concept of
diffeomorphism. Really loved topology as an undergrad. Trying to
remember if I finished that course - was about the time I realized I
couldn't pursue everything that interested me. I spend more time in
Dilbert Space than Hilbert Space these days - what a shame! (If only
I'd pursued the Math degree instead of Astronomy! I might now be an
ardent supporter of the sane and sensible notion of the leap
hour. :-) In any event, I doubt whoever wrote the ITU proposal was
thinking about Hausdorff Spaces at the time.
Ranger Brad, I'm a scientist. I don't believe in anything!
I think a little atmospherium is all we need to resolve out
troubles. Let's share!
Rob Seaman
National Optical Astronomy Observatory
Received on Wed Jan 11 2006 - 21:56:20 PST
This archive was generated by hypermail 2.3.0
: Sat Sep 04 2010 - 09:44:55 PDT