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Discussion of precise time and frequency measurement

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leap seconds finally being retired?

PK
Poul-Henning Kamp
Tue, Nov 29, 2022 7:59 AM

Jürgen Appel via time-nuts writes:

Another fun-fact for all time-nerds on the other side of the Atlantic trying
to do the intercontinental version of this experiment:
The Doppler-red-shift due to continental drift of ~1cm/year is of the same
order of magnitude: (1 cm / year)/c = 10^-18 as well.

Not to mention uplift from the most recent glaciation.

--
Poul-Henning Kamp      | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG        | TCP/IP since RFC 956
FreeBSD committer      | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

-------- Jürgen Appel via time-nuts writes: > Another fun-fact for all time-nerds on the other side of the Atlantic trying > to do the intercontinental version of this experiment: > The Doppler-red-shift due to continental drift of ~1cm/year is of the same > order of magnitude: (1 cm / year)/c = 10^-18 as well. Not to mention uplift from the most recent glaciation. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.
DM
Demetrios Matsakis
Tue, Nov 29, 2022 2:19 PM

Glacial rebound makes the Earth turn faster all by itself.  As the arctic goes up vertically, the equatorial regions have to go down and this makes the Earth rounder.  To conserve angular momentum, there is a speed up.  But a recent paper by Zotov et al says recent global warming will only speed up the Earth at 5% the rate we are seeing it.  It is ASR 69, Issue 1, January 2022, pp 308-313.

I guess we should avoid building optical frequency standards in Hawaii, as it moves much faster.  Not to mention Mauna Loa.

I was very impressed by a PTTI paper by Wolf,  late 90’s, which detailed a whole host of relativistic effects that kick in at 10^-18.  I don’t think he had continental drift in there though :)

On Nov 29, 2022, at 2:59 AM, Poul-Henning Kamp via time-nuts time-nuts@lists.febo.com wrote:


Jürgen Appel via time-nuts writes:

Another fun-fact for all time-nerds on the other side of the Atlantic trying
to do the intercontinental version of this experiment:
The Doppler-red-shift due to continental drift of ~1cm/year is of the same
order of magnitude: (1 cm / year)/c = 10^-18 as well.

Not to mention uplift from the most recent glaciation.

--
Poul-Henning Kamp      | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG        | TCP/IP since RFC 956
FreeBSD committer      | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.


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Glacial rebound makes the Earth turn faster all by itself. As the arctic goes up vertically, the equatorial regions have to go down and this makes the Earth rounder. To conserve angular momentum, there is a speed up. But a recent paper by Zotov et al says recent global warming will only speed up the Earth at 5% the rate we are seeing it. It is ASR 69, Issue 1, January 2022, pp 308-313. I guess we should avoid building optical frequency standards in Hawaii, as it moves much faster. Not to mention Mauna Loa. I was very impressed by a PTTI paper by Wolf, late 90’s, which detailed a whole host of relativistic effects that kick in at 10^-18. I don’t think he had continental drift in there though :) > On Nov 29, 2022, at 2:59 AM, Poul-Henning Kamp via time-nuts <time-nuts@lists.febo.com> wrote: > > -------- > Jürgen Appel via time-nuts writes: > >> Another fun-fact for all time-nerds on the other side of the Atlantic trying >> to do the intercontinental version of this experiment: >> The Doppler-red-shift due to continental drift of ~1cm/year is of the same >> order of magnitude: (1 cm / year)/c = 10^-18 as well. > > Not to mention uplift from the most recent glaciation. > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > phk@FreeBSD.ORG | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by incompetence. > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com