Earth sets new record for fastest rotation since atomic clock era

[gary]

The International Earth Rotation and Reference Systems Service at the Paris
Obervatory reported that on June 29, Earth set a new record for the shortest
day of the atomic-clock era: -1.59 milliseconds.

If Earth’s fast rotation continues, it could lead to the introduction of the first-ever negative leap second.

Story at timeanddate.com here :-
https://www.timeanddate.com/news/ast...rtest-day-2022

Chart here at the Paris Observatoire :-
https://hpiers.obspm.fr/eop-pc/index.php

Originally Posted by Graham Jones and Konstantin Bikos. Published 27-Jul-2022, timeanddate.com

Why Is This Happening?

What is causing the current downward trend in the length of the shortest day?

It could be related to processes in Earth’s inner or outer layers, oceans, tides, or even climate. Scientists are not sure, and struggle to make predictions about the length of day more than a year ahead. But there are tentative ideas.

At next week’s annual meeting of the Asia Oceania Geosciences Society (presentation SE05_A009), Leonid Zotov—together with his colleagues Christian Bizouard and Nikolay Sidorenkov—will suggest the current decrease in the length of day could have some relation to the ‘Chandler wobble’.

Chandler wobble is the name given to a small, irregular movement of Earth’s geographical poles across the surface of the globe.

“The normal amplitude of the Chandler wobble is about three to four meters at Earth’s surface,” Dr Zotov told timeanddate, “but from 2017 to 2020 it disappeared.”

[Dennis]

Wow, thanks Gary, no wonder that I was feeling dizzy on the day.

Cheers

Dennis

[RB (Andrew)]

This year’s really gone quick.

[Stonius (Markus)]

One and a half milliseconds is really not that small, when you think about it. I mean, a 10 millisecond delay can be detected by human ears.


I wonder what the physical distance that would work out to in terms of rotation on the earth's surface at the equator.



I could probably figure it out, but my maths-ing is remedial and it would take me all day to make sure I got it right.

[gary]

Originally Posted by Stonius

One and a half milliseconds is really not that small, when you think about it. I mean, a 10 millisecond delay can be detected by human ears.


I wonder what the physical distance that would work out to in terms of rotation on the earth's surface at the equator.



I could probably figure it out, but my maths-ing is remedial and it would take me all day to make sure I got it right.

Probably around 618 millimetres in Sydney.

[Stonius (Markus)]

Originally Posted by gary

Probably around 618 millimetres in Sydney.

So what do you do, take the circumference of the earth and divide it by the number of milliseconds in a day, then multiply that number by 1.59?


I must be doing it wrong (no surprise there!)


I have circumference of the earth at the equator (40,075,017m)
Divided by the number of milliseconds in a day (86,400,000ms)
Which gives 0.46m per millisecond travel.

Multiply by 1.59 and the earth was 0.74m 'early' on the fastest day of rotation.
Which I guess is about what you're saying.


I guess it also means that to stay at the same spot on earth relative to the sun, you'd have to drive at 1,670km/h just to have 'permanent noon'.


If my figures are right (40,075km divided by 24h)


Cool!

[blindman]

Michelson-Morley experiment proved that Earth is not moving.
Did you know?

[gary]

Originally Posted by Stonius

So what do you do, take the circumference of the earth and divide it by the number of milliseconds in a day, then multiply that number by 1.59?

Multiplied by the cosine of your latitude, about 33 degrees for Sydney.

[ChrisD (Chris)]

Originally Posted by blindman

Michelson-Morley experiment proved that Earth is not moving.
Did you know?

First I thought you were joking. Then I read your location and tag line, now I'm not so sure. I will say that that is an interesting interpretation of the Michelson-Morley experiment results.

Chris