[LEAPSECS] Solar time: From mean solar days, to mean solar years

[Ian Batten]

On 21 Aug 2014, at 08:06, Clive D.W. Feather <clive at davros.org> wrote:

> Warner Losh said:
>> Absolutely. We get leap days right because we don?t have to hear from the pope?s astronomers every year to know if it will be a leap year or not. We know for thousands of years.
> 
> And note that it was exactly that problem that led Caius Julius to reform
> the calendar in the first place.
> 
> [...]
>> Another thing we could do is [...]
> 
> Or we could decouple UTC from GMT and allow each country to decide when to
> change its offset. That subsumes the whole problem into the summer/winter
> time switch, or the "move past the International Date Line" switch, that
> the whole world knows how to handle, even if they don't all do it.

I attempted to blag my way onto the UK government consultation process, but let slip that I knew about the issue.  So I ended up as part of the expert panel at one of the meetings (the "England" one), and with the chair of ISPA and a couple of heavy hitters from the Royal Observatory diaspora.  

The meetings have now all finished and the report has gone to the minister, so I don't think I'm breaking any confidences in saying that the public opinion --- which was, after two days, astoundingly well informed and gives you faith in the idea of citizen's juries --- was to leave well alone.  ISPA, whose members now also include Google and other cloud/webserver people, made the standard argument used here: "it's a bit of a pain, and we need to improve standards and dissemination, but we can cope whichever way the decision goes".  When there's no strong driver to change, people inevitably opt for the status quo, and that's what will be in the summary that goes to the minister.

It'll be interesting to see the outcome in the UK does, in fact, vote to retain leap seconds but loses.  De jure UK time is still GMT, while de facto everyone uses UTC (even the "Greenwich Pips" are actually UTC).  But with |DUT1|<0.9s no one gets too excited about the inconsistency.  

ian