Time is an arrow with no past, propelled by the present impulse into the
future. We cannot change the past but we can affect the future based on how
we project our ideas.
The current discussion on the future of UTC and the leap second is a case
in point. We know we are all getting older and slowing down. So is the earth
in its orbits and rotations, now measurably slower. The earths rotation is
slower due to tidal friction. Time, told by sundials, defined by the timed
position of the sun in our sky is slowing down. With modern Cesium atomic
clocks we know precisely how quickly we are slowing down as we and our
planet age. You all received the notice for a meeting on the problem with
time as we experience it and time as precisely measured for so many things
like astronomy, computers, GPS and geo-location, that depend an accurate
time base, not solar time. Standard time* came in due to the railroads. Are
we being railroaded again? Daylight sayings time was introduced as a wartime
expedient like income tax. Neither were cancelled as a peace dividend.
Rob Seaman, one of the co-chairmen for this conference on "Decoupling Civil
Timekeeping from Earth Rotation", posted a note to the SML 24 July. This
conference is to address the question remains how do we reconcile atomic
with solar, orbital and sidereal time. Check this link.
http://futureofutc.org . Rob recently coauthored an interesting article
outlining the problem in the American Scientist July Aug edition. The
abstract is here.
http://www.americanscientist.org/issues/feature/2011/4/the-future-of-time-utc-and-the-leap-second
This is an excellent article. Pick it up if you can at your local magazine
rack. Otherwise I have scanned it to pdf and posted it here for a few
friends on the SML. http://www3.telus.net/public/rtbailey/SML/TimeBW.PDF
Regards,
Roger Bailey
Walking Shadow Designs
N 48.6 W 123.4
"Life's but a Walking Shadow..."
*Daylight sayings time was introduced as a wartime expedient like income
tax. Neither were cancelled as a peace dividend.
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From: "Rob Seaman" <[email protected]>
Sent: Sunday, July 24, 2011 6:26 PM
To: <[email protected]>
Subject: Re: Future of UTC / leap second
Hello,
I'd like to thank Wolfgang Dick for circulating the announcement a few
weeks ago of our meeting, Decoupling Civil Timekeeping from Earth
Rotation. While primarily a meeting on the implications of redefining UTC
for astronomical and astronautical applications, the organizers would very
much welcome submissions discussing the impact on sundials and related
technologies and their usage and stakeholders:
http://futureofutc.org
I'd also like to thank Tony Finch for circulating the link to our
preprint, and have a few comments to add to what he wrote at the time:
See also this preprint from American Scientist.
The official, more elegantly formatted, preprint is available from:
http://www.agi.com/downloads/media-center/in-the-news/Future-Of-Time-American-Scientist-July-Aug-2011.pdf
Note that the people involved in both the article and the colloquium are
in favour of keeping leapseconds.
Rather I'd say we are all in favor of preserving Coordinated Universal
Time as a representation of the actual Universal Time. Leap seconds are a
means to an end. We're willing to discuss other possible means, as has
been proven many times (over more than a decade :-) on the leap seconds
mailing list:
http://six.pairlist.net/mailman/listinfo/leapsecs
The ITU-R has also issued another questionnaire to its member states on
this issue.
The Earth Orientation Center of the IERS has its own very brief
questionnaire:
http://hpiers.obspm.fr/eop-pc/questionnaire/questionnaire.html
Humans, not just "member states" are encouraged to take a few moments and
fill it out. Your community will be affected - your community should have
a voice.
It has remained controversial at every level as it has progressed through
the ITU's bureaucracy. The final stage will be a vote at the
radiocommunication assembly next year.
Controversial indeed, however, the scope of our upcoming meeting (5-6 Oct
2011, Exton, PA USA) is to discuss the impacts and contingent
reengineering if the ITU does vote to redefine UTC. It should make for a
very engaging agenda. Of interest to the sundial community there will be
a presentation on the vision and architecture (eg, solar synchronizer and
equation of time cam) of the 10,000 year clock (http://longnow.org/clock/)
by one of their project engineers. We are also organizing a visit and
talk at the analemmatic sundial at Longwood Gardens (http://bit.ly/omBqrE)
following the meeting. Ken Seidelmann provided its accurate calibration;
the ITU's redefinition of Coordinated Universal Time would render
calibration rather a moot issue for this and all sundials.
Finally, for those in Europe and the UK, the British Royal Society is also
holding a meeting on the redefinition of UTC on 3-4 November 2011:
http://royalsociety.org/events/UTC-for-21st-century/
Contact the organizers regarding their meeting's scope and agenda (and
what they favor, for that matter).
Thank you!
Rob Seaman
National Optical Astronomy Observatory
Tucson, AZ
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