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posted by mrpg on Friday October 06 2017, @12:34AM   Printer-friendly
from the accurate-reporting dept.

A new atomic clock is even more precise than its predecessors:

It's about time. The most precise atomic clock ever made has been created by arranging strontium atoms in a grid-like pattern and then stacking those grids like pancakes.

Most atomic clocks use atoms of the isotope caesium-133. The ticking of time is measured through microwaves emitted by the electrons around those atoms jumping from a lower to higher orbit as they absorb and then lose energy from a laser.

But these clocks are constrained in how precisely they can divide time because caesium electrons have a speed limit: they can only jump back and forth 9 billion times per second. The electrons in strontium atoms can transition nearly 1 million billion times per second.

"In 2014, the world's most accurate optical clock wouldn't lose or gain one second in the entire age of the universe," says Jun Ye at the University of Colorado at Boulder. Previous caesium clocks kept time accurately to within a second over the course of 300 million years.

Now, Ye's group has built a strontium clock that is so precise, out of every 10 quintillion ticks only 3.5 would be out of sync – the first atomic clock ever to reach that level of precision.

Also at the National Institute of Standards and Technology.

A Fermi-degenerate three-dimensional optical lattice clock (DOI: 10.1126/science.aam5538) (DX)

A synchronous clock comparison between two regions of the 3D lattice yields a measurement precision of 5 × 10–19 in 1 hour of averaging time.


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  • (Score: 2) by takyon on Friday October 06 2017, @07:05AM (1 child)

    by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Friday October 06 2017, @07:05AM (#577854) Journal

    I was just explaining literally everything on that page since I think nobody knows of it.

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  • (Score: 2) by maxwell demon on Friday October 06 2017, @07:47AM

    by maxwell demon (1608) on Friday October 06 2017, @07:47AM (#577874) Journal

    What makes you think so? I guess the typical AC doesn't, but I'd expect that most logged-in users do. Note that not using it is not the same as not knowing about it. For example, I browse at -1/0, therefore there's little value to me for those controls. In addition, assuming it wasn't changed from how it worked on Slashdot, the score cap is applied after the modifiers, so you actually lose information when using them. As an extreme case, say you give a +5 modifier for Insightful posts; then you cannot distinguish between a post that was moderated Insightful once, twice, or even net moderated down to 0, but still bearing the Insightful label.

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