I'm glad to see the basic issues (finally) get some discussion. I disagree that the civil time issues don't matter. We hold the standards that underlie civil time in trust for an incredibly large and diverse set of communities. And yet, for over three years this ad hoc process of re-evaluating the UTC standard has focused on nothing but technical issues - rather naive technical issues at that. The confusion between secular and period effects is embarrassing.
UTC has proven a successful and robust standard. The time and frequency community have proven to be able stewards of the standard - right up to the point of trying to abandon the standard by the side of the road. The current standard already permits issuing leap seconds at a more frequent cadence that will allow the standard to persist for many hundreds of years, at which point a graceful update will be possible (see, e.g., ftp://gemini.tuc.noao.edu/pub/seaman/leap/leapsec.txt). There is no reason this process has to be hurried. The haste and the opaque nature of the decision making process have been offensive. A few talking points: 0) Who owns the civil time standards? We are to understand that at some point in the last few decades that control of this passed from the astronomical community to some obscure telecommunications commission. I don't see it that way. Each individual government obviously has ultimate control of their own civil timescales. For many purposes it has proven critical - for commerce and safety, for instance - to rely on an international standard. The astronomical community can point back to hundreds or thousands of years of careful stewardship of the world's clocks. Implicit in the UTC standard is the idea that civil time will continue to track the Earth's rotation. (The standard actually explicitly states that UTC should be regarded as the general equivalent of GMT.) There isn't the slightest notion hidden in the standard that this role could be abandoned by simple committee fiat. The "users" we serve may, on occasion, be annoyed by leap seconds - that does not mean that were they to understand the full implications that they themselves would choose to discard this fundamental requirement of civil time. Any mandate to reengineer UTC requires a far higher level of consensus than other standards discussions, a notoriously excruciating process under the best of circumstances. 1) There is no coherent proposal on the table, just a notion that the practice of issuing leap seconds should cease - perhaps as soon as immediately. How are we to comment on a plan that doesn't exist? 2) The Keck Observatory estimates that it would cost $110,000 to retrofit their systems to support their guess at what the new UTC standard might be. This estimate seems quite low to me, considering that Keck observing time is valued at around $50,000 per night. Just verifying the changes to all affected observing modes could require several nights. Conservatively multiply this estimate by perhaps a hundred for the astronomical community as a whole (the costs will scale closer to the number of telescopes than their sizes - even ignoring all non-telescope related astronomical applications). It would be much more expensive than Y2K remediation was for our community - we wouldn't have to just fix bugs, but rather reimplement algorithms that are fundamental to many of our activities. 3) While astronomy perhaps requires special consideration, many other technical fields would likely be affected - in addition to the rather strange collection of ham-handed projects that have appeared to be driving this initiative. Assume, for the sake of argument, that all the effects in fields from navigation to time keeping (surely we must know how this will affect our current GPS, WWV and NTP hardware and software, right?) to geography (disconnect UTC from GMT - what happens to the prime meridian?) to transportation (have we talked to our friends in air traffic control?) would be minor. But how much will verifying all these minor changes cost? Y2K remediation has cost hundreds of billions of $US - are we really to believe that a change to UTC would cost not much more than pocket change? 4) What about non-technical fields? The awareness of this issue in astronomy is currently at the few percent level. That's your best case of informing the affected communities. Has anybody even thought to ask a lawyer about potential issues? And not Jacoby and Meyers, more like Lawrence Tribe. We've learned that civil time in the U.K. is still referenced to GMT (and why wouldn't it be?). Presumably the relationship of civil time to UTC in many other countries is also cloudy. Should we change the standard before or after figuring out this situation? Can the equivalence between UTC and GMT be broken before *all* the world's countries sign off on the change? Alternately, would neighboring countries really like to return to the days before the standard time zones? You would not only have to convince the U.K. to support a drifting UTC, you would have to convince them to adopt this emasculated standard in preference to one of the last, very popular, remnants of the Empire. 5) What about cultural and political issues? The international climate is incredibly tense. Many religious traditions care deeply about calendrical issues and the timing of astronomical events. For instance, observatories get frequent requests for lunar and solar information from Moslems, Christians and Jews. Is it prudent to introduce an obscure change that can be of no possible benefit in these calculations - but that just might appear to be a deadly insult to a quarter of the world's population? Are politicians from even a single country on the globe likely to want to deal with issues like these at this point in time? 6) What about commercial interests? We have a very few projects or individuals who appear to be pushing for this change. (Although I'm not convinced any of these individuals has even once sent a message to this list.) Has anybody asked the manufacturers of commercial telescope, navigation, surveying, or - oh yes - timekeeping hardware or software what they think about it? (I'm sure that's not a complete list.) What about the related service industries such as planetarium or museum education? Millions of amateur astronomers would be able to detect the discrepancy between UTC and UT1 after only a few years. Big deal? Perhaps not, but it's a very annoying small deal multiplied by a heck of a lot of people. 7) This is a .mil mailing list. I can think of arguments for why the U.S. Department of Defense might either be backing this change to the UTC standard from behind the scenes - or why they might be ignorant of the debate, but would be completely opposed if they learned about it. I doubt that DoD would have no opinion. Has anybody asked them? More to the point - would the militaries or governments of other countries be supportive or unsupportive of the U.S. DoD's desires? To sum up: the proponents of the notion of abandoning leap seconds have some obscure agenda of their own. This change to the standard is a sop to lazy projects who either can't be bothered to use UTC correctly - or shouldn't be using UTC at all, but rather, TAI or a related timescale like GPS. In any event, many of these projects will have died a natural death before any change to the UTC standard could become a reality. The proponents of this initiative can't even be bothered to generate a coherent proposal describing their plan - one has to wonder if there is a plan at all. The change would cost the astronomical community on order $10,000,000 and would produce zero benefit. No attempt has even been made to estimate the cost to other communities. Political, legal, cultural and commercial issues? There is zero evidence that these real world concerns have been even entertained. The approximation that UTC = GMT is a useful one and should be preserved. The burden for abandoning this rests with the parties pressing for a change to the UTC standard. If there is an actual proposal to go with this "no new leap second" notion, let's hear it - hopefully it will be better conceived than the surveys that have been so narrowly worded and disseminated. Folks, this isn't just some obscure technical question. Rob Seaman National Optical Astronomy Observatory