3 ms·

I love this quote: > Scientists also noted that this past summer, on July 19, the shortest day ever was recorded—it was 1.4602 milliseconds shorter than the st

I love this quote: > Scientists also noted that this past summer, on July 19, the shortest day ever was recorded—it was 1.4602 milliseconds shorter than the standard. It’s so interesting to think about (a) how incredibly stable the rotation of the earth in in human terms, and also (b) how far we’ve come to be able to measure something so vast (the rotation of our planet) against a scale so tiny (milliseconds - shorter than an blink). The world is amazing :)

simonh 6y ago
Atomoc clocks are nuts accurate nowadays. They’re so good you can measure the relativistic gravitational time dilation effect of a height difference of a few inches. It takes a while, like about a year I think, but you can do it.
- Technically 6y ago
  People talk about rockets and computers, but to me atomic clocks are the pinnacle of human achievement. So many other technologies are built off of accurate time measurement, and it's a very clever mechanism (at least the one in Boulder is that I'm aware of). The semiconductor is pretty good, too, but not nearly as clever.
  - dralley 6y ago
    A significant amount of the "cleverness" is in how semiconductors get made rather than the transistors themselves.
    - Technically 6y ago
      Yes, I meant this more about my appreciation of the clock rather than my ignorance of semiconductors and rockets, which I can assure you is massive.
  - dredmorbius 6y ago
    Precision is a phenomenal enabling technology of itself. In time, space, energy, matter (purity, dimensions), etc.
- deleted 6y ago
  [deleted]
Florin_Andrei 6y ago
BTW, after seeing some "spiritual" comments on Facebook inspired by the news, I posted this: It changes all the time, the variations are small, the real long term trend is actually for the rotation to slow down, we are not now at a historic extreme. The talks about the leap second are due to cumulative deviations over a few decades, which are normal. The reporting is not factually wrong, but it's limited. Check the LOD (length of day) graphs on the Lick Observatory site: https://www.ucolick.org/~sla/leapsecs/dutc.html https://www.ucolick.org/~sla/leapsecs/dutc.html
- studius 6y ago
  Or, possibly, it stays the same without variation and the measurement was flawed. A recent study indicates our most accurate clock may not be infallible[1]. P.S. gravity isn't constant either[2]. [1]- https://www.nature.com/articles/s41467-020-18264-4 https://www.nature.com/articles/s41467-020-18264-4 [2]- https://en.wikipedia.org/wiki/Gravity_anomaly https://en.wikipedia.org/wiki/Gravity_anomaly
  - Florin_Andrei 6y ago
    Yeah, that's crackpot stuff (the facts are right - but completely unrelated to the topic at hand). What is it about the Earth's rotation that draws all the crackpot "theorists"?

simonh 6y ago

Atomoc clocks are nuts accurate nowadays. They’re so good you can measure the relativistic gravitational time dilation effect of a height difference of a few inches. It takes a while, like about a year I think, but you can do it.

Technically 6y ago
People talk about rockets and computers, but to me atomic clocks are the pinnacle of human achievement. So many other technologies are built off of accurate time measurement, and it's a very clever mechanism (at least the one in Boulder is that I'm aware of). The semiconductor is pretty good, too, but not nearly as clever.
- dralley 6y ago
  A significant amount of the "cleverness" is in how semiconductors get made rather than the transistors themselves.
  - Technically 6y ago
    Yes, I meant this more about my appreciation of the clock rather than my ignorance of semiconductors and rockets, which I can assure you is massive.
- dredmorbius 6y ago
  Precision is a phenomenal enabling technology of itself. In time, space, energy, matter (purity, dimensions), etc.
deleted 6y ago
[deleted]

Florin_Andrei 6y ago

BTW, after seeing some "spiritual" comments on Facebook inspired by the news, I posted this: It changes all the time, the variations are small, the real long term trend is actually for the rotation to slow down, we are not now at a historic extreme. The talks about the leap second are due to cumulative deviations over a few decades, which are normal. The reporting is not factually wrong, but it's limited. Check the LOD (length of day) graphs on the Lick Observatory site: https://www.ucolick.org/~sla/leapsecs/dutc.html https://www.ucolick.org/~sla/leapsecs/dutc.html

studius 6y ago
Or, possibly, it stays the same without variation and the measurement was flawed. A recent study indicates our most accurate clock may not be infallible[1]. P.S. gravity isn't constant either[2]. [1]- https://www.nature.com/articles/s41467-020-18264-4 https://www.nature.com/articles/s41467-020-18264-4 [2]- https://en.wikipedia.org/wiki/Gravity_anomaly https://en.wikipedia.org/wiki/Gravity_anomaly
- Florin_Andrei 6y ago
  Yeah, that's crackpot stuff (the facts are right - but completely unrelated to the topic at hand). What is it about the Earth's rotation that draws all the crackpot "theorists"?