Saturday , June 25 2022

So Accurate Atomic Clocks can measure gravity



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atomic clock

an older version of & # 39; ultra-stable atomic clock & # 39; Lattice ytterbium f & # 39; NIST. The atoms & # 39; Ytterbium are generated in & # 39; oven (large metal cylinder on the left) and sent in & # 39; vacuum chamber at the photo center to be manipulated and spermat through a & # 39; lasers. The laser light is transported to clock b & # 39; five fibers (such as yellow fiber center of & # 39; bottom photo). (Credit: Burrus / NIST)

Time, like money, it seems only important when it ends. But for the physical, time is always & # 39; great importance. The relativity tells us that the flow & # 39; time depending on the circumstances under tkejjilha in: watches mark on the mountain faster than the level & # 39; land, for example, and the faster you go the faster your clocks go. The time depends on the space.

But now, thanks to technological advances in atomic clocks – the most & # 39 devices, keeping accurate time developed – we can discuss things, and determine physical parameters b & # 39; more precisely by studying -mogħdija time. Our understanding of space depends on the time.

The new clocks, described today in the journal nature, Which also promises better atomic clocks usually promise: improved technologies & # 39; timeliness, communication and navigation. But in addition to their knowledge of the physical space & # 39; around, the devices can also help find gravitational waves, trying to forecast the ratio and the hunt for dark matter. Everything, just a super-accurate clocks.

In Atomic Arloġġjar

It can & # 39; everything seems quite complicated (and it is), so let's start with the basics. As the paper give useful authors, "The passage of time is traced by summing oscillations & # 39; reference & # 39; frequency, such as the World revolutions or swings & # 39; pendulum. By a & # 39; referencing & # 39; atomic, frequency transitions (and thus time) you & # 39; measured with & # 39; more precisely than any other physical quantity. "So, count how often exceed -atomi between specific energy levels and have ticks and more precise holes.

The leading name in atomic clocks is the National Institute of Standards and Technology (NIST), and from which comes the today's research. The most recent clocks rely on 1,000 atom & # 39; ytterbium, chilled to almost absolute zero, trapped within grids 1-D (ie, columns) made of laser beams. By all measures the performance of the atomic clock – minimize atomic frequency errors, ensure that the ticks are stable, and their results are reproducible – the NIST researchers have produced only accurate unbelievably watches. The bars & # 39; their error are on the order of & # 39; 10-18Or & # 39 billion, billion.

The Shape of Things

In fact, these atomic clocks are so accurate, they are actually sensitive to gravitational influences. Usually, the relativistic gravity quirks to arrange the flow of & # 39; time too minute for us to note – but no more. As told the authors, "If these clocks were compared long baseline or used for remote comparisons & # 39; clocks around the world, the measurement is limited by gravitational knowledge on the Earth's surface . " That is, they are so precise that the only thing you can & # 39; change the ticks and their tocks be gravity itself. higher Watches, & # 39; away from the Earth's mass, mark faster than clocks & # 39; down, thanks to relativity.

This agreement is a key science of geodesy, measuring the shape of the Earth and the gravitational influence. Our current picture of the exact surface of the planet depends on satellites and computer modeling, to provide a fairly good resolution, up to a few centimeters. But these atomic clocks bring that resolution & # 39; below, only one centimeter. Armed with & # 39; both of these watches, researchers can compare the sea level in & # 39; two different continents, the precise height of & # 39; mountain, or any other measure based on high (and hence gravity) who wish to make.

And as atomic clocks are so sensitive to gravity, can serve as a sort of & # 39; detector for any related activity. Gravitational waves, as they pass minnna and this planet, showing itself in & # 39; these messages & # 39; these watches. extremely subtle experimental tests of theories of & # 39; Einstein are now also possible. And most tantalizingly, technology can & # 39; help to detect small quantities of & # 39; Dark matter, invisible stuff that only interacts with gravity, and forms the bulk of the material universe.

To be clear, these are still only possibilities. The authors newly built atomic clocks and these have proved accurate. But, now that they know the technology works well, new future & # 39; discoveries of physics can & # 39; be us. It's time.

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