Wednesday , September 28 2022

These atomic clocks are so precise They can Measure-the distortion of space-time – Science News


These clocks are so ACCURATE They'd lose just half a second ow They lasted The Age of-the-Universe. That's 14 billion-years.

key points

Key points:

  • The in-the-world ACCURATE must clocks are atomic clocks, lasers and electron Which use technologies to September their "ticking" rate
  • A new pair of ultra-precise atomic clocks based on-the element ytterbium have record-breaking Stability and synchronicity
  • By Measuring space-time distortion, like atomic clocks These help Could Explore Earth's interior-the Detect and dark matter

But They won't-the BE Used to keep trains running on time. The clocks exquisite Precision, outlined today in Nature, Means They can Measure how distorted space-time Under gravity forces.

Eventually, astrophysicists Could enlist their help to Detect mysterious dark matter.

More immediately, the-clocks Could tell us What's going on inside-the Earth by precisely mapping Our planet's Bumps and lump – ow-the clocks are shrunk, That is.

Study co-author Will McGrew, a PhD student at-the National Institute of Standards and Technology in-the US, said the-clocks "ticking" Produced by the oscillations of the electron radiation emitted whens ytterbium atoms are excited by lasers.

They TURNS out the tick, the Unison Almost perfect, 500 trillion times a second.

"Measuring time and frequency Suchi With an Incredible Accuracy really POWERFUL provides a lens to view the natural world," Mr. McGrew said.

Atomic time 101

Was Measuring time based on astronomy. For instance, the-length of a day Was Determined by one spin axis of the Earth on budgets.

But Astronomical phenomena Tend to slow down or speed up.

Our days are lengthening, by an extra 1.7 milliseconds EACH Century, thanks to our gravitational tango With The Moon.

So whiles time Astronomical mights do for timetabling and Suchi, science Demand Precision.

Print and wherein the atomic time to shine.

Looking to-the-Rather Than Heaven, Print form of time-keeping drills Into-the waves of radiation shrugged off by atoms whens they're bathed in laser light.

What makes atomic clocks, tick?

What makes atomic clocks, tick?

  • A second DEFINED by-the movement of the electron in a cesium-133 atom, Which COMPRISES a nucleus – containing 55 and 78 proton Neutrons – Surrounded by 55 Electron
  • As electron whiz around-the nucleus, They occupys different orbits or "energy level"
  • Electron can "jump" Between Levels whens They ABSORB or release a Specific Amount of energy
  • The energy emitted EACH time an electron makes a jump the particulars ALWAYS the-Same, and the in-the form of microwaves
  • Thoses particulars microwaves have a frequency (the number of full waves Completed second EACH) Which Can Be Measured as-the atom's "ticking" rate
  • Cesium-133 "sticks" Every second 9,192,631,770 times

They sound super Futuristic, atomic clocks pocket Have Been around for More Than 60 Years.

The first atomic clock ACCURATE That Was Enough To Be Used to September-the time Was built in 1955 at-the UK's National Physical Laboratory.

It Was ACCURATE to a second in 300-years.

Some 12-years later, the-the-cesium atomic clock becames international standard time, and over time, atomic clocks rat becames more ACCURATE.

Modern atomic clocks use technologies Which strontium or cesium lose one of ytterbium INSTEAD Every second 300 million-years or so.

More Than time-keepers

Atomic clocks, Precision Means They've Tested Einstein's general theory of relativity, Which predicted that time runs faster or slower the- Influence of different gravitational forces.

In other words, a clock placed on a satellite orbiting Earth, Which Experiences Higher "gravity Potential", Will Than a clock tick faster at sea level.

And theres Already atomic clocks are whizzing around on the Earth Satellites That take Advantage of this time dilations effect.

We would not have-the global positioning system, or GPS, without them.

Another use technologies of satellite-mounted atomic clocks to accurately map the Earth's size, shape, orientation in space and mass distribution, collectively called "geodesy".

Satellite geodesy usually INVOLVE timing how long trip-the-light Takes to Make Between distant points, Suchi as Shining a laser up to a satellite and timing how long it Takes for it to bounce back to a receiver on Earth.

GPS geodesy to the ACCURATE around a CENTIMETER, said Matt King, Who Uses satellite geodesy at-the University of Tasmania and was not Involved With The study.

With a Higher pocket clocks "tick" rate – That is, Higher frequency – would not have to use technologies used for light. They Could use technologies-the-effects of relativistic gravity.

Print the What Mr. McGrew and colleagues wanted to ACHIEVE HIS With their atomic clock.

INSTEAD of cesium, They Used ytterbium. The radiation waves emitted by ytterbium atoms oscillate nearly five orders of Magnitude faster Than thoses From cesium atoms.

In their paper, the-the-clocks That team showed were exceptionally stable – Losing or gaining time Almost imperceptibly – Almost perfectly ticking in Unison.

So by comparing the-Difference Between two ytterbium clocks ticking placed on separate continent, a height-the-person Could feasibly Measure Difference Between Under-the clocks to a CENTIMETER.

Harnessing the-Precision of ultra-sensitive atomic clocks Would like Having "a telescope Looking WITHIN", said Professor King.

"Let's say you have an Earthquake," he said.

"If you can Measure That really precisely, you can Learn About Fundamentals about-the interior of-the-earth, like viscosity or runniness budgets."

How the Earth bounces back whens glaciers melt sinks or whens's groundwater pumped out, too, tracked Could BE With atomic clocks.

And Seeing how-the-ground lifts and around a volcano subsides, even on a sub-scale CENTIMETER, volcanologists Could tell how the magma moving around Below, Professor King Added.

"That Combine With seismology, and you get a real picture of What's happenings are on the inside."

Big Applications, compact clock

So What's Stopping atomic clocks being wheeled out to volcanic and Earthquake-around-the-world places Risky?

Simply, ytterbium-the clocks are big to move.

"[The clocks] basically take up a fairly Large laboratory, "Mr. McGrew said.

They NEED because the Print a Bunch of Large lasers to work.

A couple of cool lasers-the ytterbium atoms to a fraction over absolute zero (-273 degrees Celsius), whiles others hold Chilled-the atoms in place.

Mr. McGrew and colleagues have HIS Already Started work on-the-shrinking systems.

Professor King optimistic That the ultra-precise atomic clocks one day Will BE compact Enough To Be Used on Earth as well in space.

"Computers Used to fill whole rooms as well.

"We mights 20 BE-years away, the sooner BE mights, ow These pocket [ytterbium clocks] Can Be miniaturized and Precision Keep on Increasing the-ow, there's no shortage of THENI Applications. "

Weird and wonderful

Down-the-track, atomic clocks Could BE INVOLVE That Used for Experiment Measuring the-tiniest distortion in space-time, like-the incredibly subtle stretching and squashing of matter caused by a gravitational wave.

Dark matter Take, for instance. Astrophysicists know the dark matter out there, and that's it Forms for around a quarter of mass and energy in the-the-Universe.

But its a "dark" nature – That it does not SEEM to Reflects, ABSORB radiation or issuers – Means to the very Difficult to Detect.

One model of dark matter Suggest mights the INTERACT With Changing the-ordinary matter by a fundamental constants of nature, Mr. McGrew said.

And wherein the atomic clocks Print mights help astrophysicists Learn a little about-the elusive stuff.

"Say there's a big dark matter's That object passes through a laboratory That Has an ytterbium clock and a strontium clock," Mr. McGrew said.

"[The dark matter] Would Affect ytterbium by some factor, and THENI Other strontium by some factor.

"By Measuring the-Difference Between-the two clocks, you Could Detect-the-dark matter object's Presence.

"These are extremely subtle-effects, whens pocket you can make measurements of Accuracy With 18-digit level, you Could Detect them."

And, of course, there are Purposes we've not yet dreamed of.

"The people Who first made atomic clocks didnt know They were building a GPS device," Mr. McGrew said.

"I think there's something to SIMILAR's To Be said about atomic clocks – That their Salient grape, grape important Been Applications have not thought of yet."

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