atomic clocks tagged posts

The Length of Earth’s Days has been Mysteriously Increasing, and Scientists don’t know Why

The length of Earth's days has been mysteriously increasing, and scientists don't know why
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Atomic clocks, combined with precise astronomical measurements, have revealed that the length of a day is suddenly getting longer, and scientists don’t know why. This has critical impacts not just on our timekeeping, but also things like GPS and other technologies that govern our modern life.

Over the past few decades, Earth’s rotation around its axis—which determines how long a day is—has been speeding up. This trend has been making our days shorter; in fact, in June 2022 we set a record for the shortest day over the past half-century or so.

But despite this record, since 2020 that steady speedup has curiously switched to a slowdown—days are getting longer again, and the reason is so far a mystery.

While the clocks in our phones indicate there are e...

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Quantum Sensors: Measuring even more Precisely

Two teams of physicists have designed the first programmable quantum sensor, and tested it in the laboratory. To do so they applied techniques from quantum information processing to a measurement problem. The innovative method promises quantum sensors whose precision reaches close to the limit set by the laws of nature.

Atomic clocks are the best sensors humankind has ever built. Today, they can be found in national standards institutes or satellites of navigation systems. Scientists all over the world are working to further optimize the precision of these clocks...

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Signals from Distant Stars Connect Optical Atomic Clocks across Earth for the first time

Fig.
Antennas and optical lattice clocks used in the measurements

Upper left: Transportable 2.4 m antenna installed at the INAF radio observatory in Medicina, Italy.
Upper middle: Transportable 2.4 m antenna installed at NICT in Koganei, Japan.
Upper right: 34 m antenna located at NICT in Kashima, Japan.
Bottom left: The ytterbium optical lattice clock IT-Yb1, operated at INRIM in Torino, Italy.
Bottom right: The strontium optical lattice clock NICT-Sr1, located at NICT in Koganei, Japan.

Transportable radio telescopes could provide global high-precision comparisons of the best atomic clocks. Using radio telescopes observing distant stars, scientists have connected optical atomic clocks on different continents...

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