[LEAPSECS] Time on time

[Rob Seaman]

On Nov 30, 2011, at 6:48 AM, Daniel R. Tobias wrote:


> On 23 Nov 2011 at 18:14, Rob Seaman wrote:

> 

>> The Long Now 10,000-Year Clock is on the cover of Time magazine this week:

>> 

>> 	http://blog.longnow.org/2011/11/22/time/

> 

> The American version and/or the foreign ones?  Time has been under 

> some criticism lately for putting covers on weightier political 

> topics in the overseas editions while using more "fluffy" subject 

> matter domestically.

> 

> http://on.fb.me/uxdox2


Yeah, I saw that the other day.  Since this is a special issue, perhaps the same cover is used wherever it's marketed.


> Speaking of time, what sort of time is the Long Now clock keeping, 

> anyway?  Solar, atomic, or something else entirely?


Solar.  See our paper:

	http://www.cacr.caltech.edu/futureofutc/preprints/10_AAS_11-665_Hillis.pdf

If UTC is redefined, clocks carried by visitors will drift away from the actual time-of-day as provided by the Clock's orreries.  The tick resolution is 5 minutes, emphasizing again the difference between precision and accuracy (secular drift).  The clock is also a calendar and it goes to great lengths to avoid miscounting the days, even should the Sun be blocked from the sky for many decades.

Rob