[ExI] The most accurate clock ever

Thu Nov 29 16:52:00 UTC 2018

From: extropy-chat <extropy-chat-bounces at lists.extropy.org> On Behalf Of John Clark
Sent: Thursday, November 29, 2018 6:20 AM
To: ExI chat list <extropy-chat at lists.extropy.org>
Subject: [ExI] The most accurate clock ever

In yesterday's issue of the journal Nature Scientists at the National Institute of Standards and Technology (NIST) reported they have made a new type of clock that is the most accurate ever, it's called a Ytterbium Lattice Clock. It's about 100 times better than any previous clock, if set at the time of the Big Bang 13.8 billion years ago today it would be off by less than one second.

https://www.nature.com/articles/s41586-018-0738-2

It's so good the main source of error is due to General Relativity, if you lift the clock up by just one centimeter the Earth's gravitational field is slightly weaker and so the clock runs noticeably faster, that may be why NIST is now working on a portable version of their Ytterbium Lattice Clock. If GPS satellites had clocks this good they'd know where they were relative to the Earth to within a centimeter and so could tell users on the ground where they were within a centimeter; and that would be more than good enough for jet fighters to automatically land on aircraft carriers without a pilot, even at night in a heavy fog in a bad storm with the deck tossing up and down. It would be by far the best instrument ever made to detect tiny changes in the gravitational field, and that would make it much easier to find things buried deep underground. The Earth just became more transparent. It might even be used to detect Gravitational Waves and Dark Matter.  

John K Clark

John just a coupla comments please.  The time error measurement is (as I recall) a consequence of Special Relativity rather than General Relativity which is a tiny nit, but your extrapolation to landing a jet fighter using an atomic clock is… I ain’t buying it.  We know of gravitational anomalies which would swamp the heck outta that tiny difference of (I can estimate this (a cm delta in altitude is (6.37E8)^2 or about 1 part in 4E17) and that’s just the gravitational delta, before we even translate to time dilation measured over an interval short enough to be relevant to a deck landing.

We know we have gravitational anomalies at the surface of the sea waaaay bigger than that, three or more orders of magnitude.  So… no landing drones on carriers that way (we already have ways to do that (because high-frequency doppler doesn’t know or care if it is dark, rainy or foggy)) but your idea might have merit in mapping gravitational anomalies on the sea floor.  This whole notion might allow us to map the deep ocean floor and perhaps find stuff we want down there (maybe (I need to do some calcs on that.))  

We already know of gravitational anomalies big enough to be noticed by satellites, and this leads me to another cool notion you probably know about better than I do: variation in magnetic field also produces time dilation.  Reasoning: Maxwell’s equations tell us a varying magnetic field induces a magnetic field, which is an energy transfer (ja?) and Special Relativity gives us the tools to deal with that, so we take that c^2 factor (also in that E17 range) and if this new atomic clock can measure stuff down there, we might have a new magnetic field anomaly detector better than what we had before.

If this is so, this would be even more cool, because the stuff we might want on the sea floor is more likely to cause a magnetic signature than it is to cause a gravitational anomaly (it’s why those metal detectors in the airport work on that principle rather than gravity.)

Is this a cool time to be living or what?

spike

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