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NIST's New Atomic Clock Is So Precise Our Ability To Measure Gravity Constrains Its Accuracy (vice.com)
dmoberhaus writes: Researchers at the National Institute for Standards and Technology (NIST) have developed an atomic clock that is so precise that our models of Earth's gravity aren't accurate enough to keep up with it. As detailed in a paper published this week in Nature, the atomic clock could pave the way for creating an unprecedented map of the way the Earth's gravity distorts spacetime and even shed light on the development of the early universe. "The level of clock performance being reported is such that we don't actually know how to account for it well enough to support the level of performance the clock achieves," Andrew Ludlow, a physicist at NIST and the project lead on the organization's new atomic clock, told me on the phone. "Right now the state of the art techniques aren't quite good enough so we're limited by how well we understand gravity on different parts of the Earth."
So now it's device that can measure not just time, but gravity too.
If it weren't for deadlines, nothing would be late.
Sure internet lag, and performance of our PC especially in terms of the time clock wouldn't matter... But darn it, I want my PC to have accurate time.
If something is so important that you feel the need to post it on the internet... It probably isn't that important.
He'll figure it out.
Why would you care if it were off by a millionth? Your PC clock frequency is off by more than that already. It's probably already wrong the instant you sync it, not being designed to retain that coherence.
Because I want my clock to be accurate.
It is like having speakers that go to 11
If something is so important that you feel the need to post it on the internet... It probably isn't that important.
Life in prison is a looooooong time, Trumptards. We're going to make sure you're there every femtosecond until you die, traitors.
you don't get it do you? USA after 9/11 rainbowlution has been "changed" into another brick in the stonewall for rioting aka penal colony of brexit empire. So what is the meaning of prison inside the prison? It's a trick, misdirection, etc.. You know "waterboarding" is about paddling those boards on water, prolonged uncomfortable stress positions is about yoga, etc.. In real life guantanamo probably serves as lulzboat Club Med facility.
More like you want a radio station to play at 120,000 bit rate, but your crappy local player only supports 128. Better analogy.
Since you can measure gravity extremely accurately, and gravity varies with height, does that mean they've just invented an extremely accurate altimeter?
Because I want my clock to be accurate.
It is like having speakers that go to 11
Can it get us off this pointless time changing twice a year?
Damn! I wish I knew if you're a human! That's some funny shit!
If you pay us a couple million a year, we probably won't create any black holes around it. Just insurance ya know? /s
Because I want my clock to be accurate.
It is like having speakers that go to 11
Wah..well, why don't you just make 10 louder instead - and every other number?
And...so, it's going to bother you that your computer time is a ten thousandth of a second off - even after its useful life is up?
Do you even know what does word "human" even mean? For starters you have to try figuring out some very important security related issues about cuckoos nests. You know they are not only ticking orange colored rube goldberg machines that are used for measuring time, disturbing audience at the turn of the hour with a little bird making noises. So that part is about unobvious invisible issues of not so modern slavery. What is more disturbing is the issues about "oldboys" who kill their siblings for no reason at all helping to answer that question abut nurture or nature. You know the "oldboy" was nurtured in exactly the same manner as the other kids, yet he executes all his "siblings" one by one with bare hands. Some sort of strange martial law implemented by using mixed martial arts. Try thinking about movie title "one flew over cuckoos nest". Notice if you treat word "over" as phrase used in military radio communications jargon (Roger/ Wilco / Over / Out / Read / Copy) that movie title is not so obvious. It's as if they are signaling two part message - 1: "one flew" (maybe air force one) 2: cuckoos nest (whatever that means).
Because I want my clock to be accurate.
It's a security feature. It allows you to require krb5_deltat < .000000000000000001
#DeleteChrome
Gravity also varies depending on where you are, based on how dense the material underneath you is.
https://en.wikipedia.org/wiki/Gravity_gradiometry
They've been using this for years for mineral exploration and, it's rumored, that submarines can navigate underwater using these gizmos.
Trump Jr. is about to be raped to pieces in Federal prison for life and all you can do is crack jokes about it, lol? That's unfair!
And behind Door #2 time is running out for WWVB.
The low frequency WWVB standard and short wave clock time standards seem have time running
out for them.
https://www.voanews.com/a/time...
It may simply be that we will know with more precision when infrastructure has its plug pulled.
GPS time is likely better than NTP time for computers.
Clocks like this may allow for the elimination of almost all Olympic timing errors and ties.
I can see headlines... runners fail to best Usain Bolt's best time by one Picosecond +/- 2.7 Femtoseconds.
Truth is stranger than fiction, but it is because Fiction is obliged to stick to possibilities; Truth isn't. Mark Twain.
That's unfair!
What's unfair is that his jokes are so lame! This topic deserves better jokes, and they should be easy to produce.
So get cracking on that spacetime gravity problem!
Prove it. Show us your taxes, bring it.
Can I run beowolf cluster of them?
Can be used to make gps geolocation more accurate among other things.
I was reading about atomic clocks and had a thought. Currently, it's possible to measure change in height by about a meter, due to gravitation affects (time dilation).
The question is, how sensitive must your time piece be in order to measure the effects of a person? That is, could there be some science fiction machine that can effectively see through walls to detect mass, or would that not be possible (negative mass or something)?
Well, using values M=100 kg (mass approximately of a person) and r=1 (distance of 1 meter) gives a time dilation value of 0.99999999999999999999999992574174
Which I think means you would need a clock that can measure time discrepancies around 1x10-24 seconds, give or take.
If the current trend continues (ha!) -- call it moore's law of clocks -- which increases precision by about an order of magnitude per decade, it will be possible in about 130 years.
What is the Allais Effect?
For this reason, God sends them a powerful delusion(operation of wandering)(planet) so that they will believe the lie.
Working of Error
Build a set of them, place them in various places, use them to make a high resolution gravity map. Move them around as needed to focus resolution on interesting features.
It's not just height, there's also density, and that at different depths.
Useful would be unmanned submarines that can be parked on the ocean floor for extended periods of time, and a second set of subs that go out and collect data.
I would bet a gravity map of the Chicxulub crater area would be amazing, and might become a template for finding other large impact events we haven't noticed yet.
"our models of Earth's gravity aren't accurate enough to keep up with it."
It's just a theory.
It's not like it was a law or something.
They have to use one of these clocks on the other side of the planet from her fat ass to get accurate results
News at 11
"Hey, man. All we represent to them, man, is somebody who needs a haircut."
You can get time accurate to within about a thousand to a millionth of a second with PTP, using network time as your reference. That's the time standard used by thr vast majority of people, network time aka ntp time aka internet time, which is closely synced to GPS time.
So which time do you want to consider "correct" - the time used by 98% of the precision clocks, or the time used by one clock in Boulder?
NTP is super easy to use and pretty darn accurate as well. PTP is quite a bit more accurate, with microsecond synchronization within your network.
sorry, but i can't relate to that quote - i thought that movie was unwatchable. Peter Fonda didn't make sense in that role, unless you look at word "biker" as indicated that someone is "bi" you know bisexual, someone who is not uneasy when frequenting blue oyster establishments for bareback riding purposes.
But darn it, I want my PC to have accurate time.
The optical lattice clocks they're talking about "would take longer than the age of the universe (13.8 billion years) to lose a second." (from: Scientists Build Atomic Clocks Accurate Enough to Measure Changes in Spacetime Itself). If you think your PC will last that long, I want to know more about it than the clocks... :-)
It must have been something you assimilated. . . .
...put the crack pipe down and walk away slowly...
But darn it, I want my PC to have accurate time.
You can buy an atomic clock on a chip, such as the SA.45S from microsemi.
A dev kit version with serial output runs just under a thousand bucks for quantities of one, and would give you a legit strata-0 time source.
It's not as accurate as this new atomic clock NIST has, this one will drift by 10^-11 seconds per day, but it's far far cheaper.
Gravity doesn't distort spacetime. It is the effect not the cause.
The accuracy would only be valid for its own time frame, though. As soon as you need to send the time anywhere else, and you have to, even if it's just to a circuit to read the time from, the accuracy depends on stability of the environment. Any kind of change in acceleration, including but not limited to gravity, will cause a cumulative difference over, well, time, for lack of a better word.
Someone storing large amounts of metal in a nearby building, or Boring a tunnel underneath might be enough to cause drift that must be compensated for. To say nothing of factors like tidal forces, and even how the earth's own orbital speed decay over the aeons cause time variations.
But it's darn accurate for its own time frame.
Guarantee that the work Ludlow describes was primarily done by postdocs. NIST doesn't want anyone to know how the sausage is made. And most of the sausage doesn't taste very good.
when worn by obese or anorectic people :-)
I have good news and bad news for you.
The offset value we log isn't the actual difference between your clock and the peer clock, and the logged value is seconds, not milliseconds. If you see 0.08 in the log, that means we're *assuming* that you're about 0.08 *seconds* off from that peer.
If you ping a server "thousands of miles away", you'll notice each ping takes a different number of milliseconds. That difference in ping times, or jitter, is pretty much a hard limit on sync accuracy with the NTP protocol. If you get a response from a server thousands of miles away saying "it's exactly midnight", we don't know if that packet was generated 30ms ago or 35ms ago. So that loses 5ms of precision.
Back to your peerlog. The last four fields show the assumed offset, delay, dispersion and jitter (root mean square). Take delay, multiply by 0.25, then add the jitter, and that's roughly the accuracy you can expect. If you're using ntpclient, add the dispersion, as that's the dispersion of the server. If you're using ntpd, your dispersion value is arough estimate of your accuracy - in seconds.
The good news is, your ISP's DNS server and gateway are many milliseconds closer, and ine or both are probably NTP servers. You CAN get much more accurate time, you just need to use servers that are much, much network-closer to you, such as your ISP's DNS or gateway.
The reason for choosing the closest server may merit more explanation. If you're on the west coast and you query a server on thr east coast, your accuracy suffers with every router and switch along that path, so you end up with some unknown offset from the NTP server's time. ISPs and geographically disperse companies don't have that problem. Here's why.
Comcast will have a DNS server / ntp server in Houston. It may have a GPS, tdma, or LTE reciever locally connected, but most importantly it peers with their servers I Miami, Denver, and San Jose. The one in Miami peers back with Houston - and Miami, PLUS San Jose and a tier 1. All of the Comcast NTP servers have to estimate the time sync, but *they all arrive at the same estimate*, because they peer with each other multilaterally. So they all end up with the same time, network time.
By getting your time from a nearby server that does mutual peering, you're getting network time from a server that is only a few milliseconds away, amd probably a *consistent* number of milliseconds, so ntp can make accurate estimates of delay.
It's not about the quote as much as the person who said it. You remind me of him a bit, maybe more in Apocalypse Now. Still don't know if you're human. Too bad, because I would like to friend you. Oh well, it's been a slice.
So to sum up.
You have atomic clocks based on atoms.
Atoms with electric forces, strong forces and weak forces etc.
You have gravity, an unexplained force.
You have a hypothesis as to how gravity affects these electric/strong/weak forces.... aka "it bends space and time", these forces operate across space and time, so it affects these forces by bending space and time....
In other words you accept that somehow gravity and electric and strong and weak forces are all connected 'somehow'.
It just comes down to the *how*.
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I think Gravity is [BIND X POSTULATE] for some harmonic of F. Just as every other binding force from Strong force, to weak force to electric force, to how galaxies bind to how universes bind to how light binds to matter... it's all oscillating electric field aka [BIND X POSTULATE].
Postulate J4: https://science.slashdot.org/comments.pl?sid=12885862&cid=57628780
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Carrier wave based gps locations are already down to a couple centimeters and have been that way for many years (price has come down a lot though). The wavelength of the signal and corrections for the ionosphere will limit that from getting much smaller. On the other hand, measurements for the those ionospheric corrections could be made better, and they are already used as a way to monitor the ionosphere for space weather research.
We know how to convert times between frames, and this has already been addressed to some degree since the 1970s for global time systems.
International Atomic Time (TAI) is an average of many different atomic clocks at standards institutes around the world. By the 70s it was already known that the clocks differed more so than their accuracy limits such that the average time represented some weird average of the clock's altitudes. So instead, since 1977, times are corrected before averaging so they all represent the time at a defined sea level geoid. Terrestrial time is based on TAI, with an offset, is a standard time used for astronomical measurements from the surface of the Earth so they would all be in the same frame.
Two other variations exist, the Barycentric Coordinate Time (TCB) and Geocentric Coordinate Time (TCG), which represent a frame of reference in the center of the Solar System or in the Center of the Earth, minus the gravitational field of the relevant body. These are used to describe orbits in the solar system or in the Earth-Moon neighborhood, respectively, in a consistent frame.
These time systems do depend on a geodesic model of the Earth, and so that does get refined and improved over time.
OK so I propose an experiment
If earth can affect an atomic clock by 'gravity bending space and time', and gravity is really an electric harmonic of F force. You can affect the atomic clock with an oscillating electric field at F. I don't even need to tell you F because you already have a model of it (see below).
After that, stop pissing around and give me my time machine, warp drive, miniaturization machines, free energy and so on.
Really, if earth can affect an atomic clock, you can. Universe F resonance be damned. Earth is nothing, and we are nothing and earth can change F so we can change F. If we can change F, we can slow or speed up time. Time machines, aisle 3, Walmart.
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You already know what I'm saying is true.
I saw on Reddit a QM model of a 720 degree spin, which I recognized as hydrogen (3 axis: F2 wrapper, F1 wrapper, F1 wrapper). It was right there, screaming "I'm a 3 axis oscillating electric field" in full colour.
I finally found that F donuts *are* prime, you already knew this, I thought it was a topology rule, but no, it's in some obscure swiss physics paper, I didn't need to tell you how an F-donut twists on itself (postulate I4).
YOU LOT ALREADY KNOW ITS AN OSCILLATING ELECTRIC RESONANT FIELD.
I found this, you are soooo close there. You have W = wave amplitude (yep that's always true), you are clearly measuring the monopole and thinking its the whole electron, but the basic shapes the monopole traces out.... identical.
https://www.youtube.com/watch?v=jgw47XTZnjU
There is no W*2, you're simply measuring an F2 donut's effect on a monopole, but the model is there.
Why is W = Amplitude *always* true?
Consider a wave propagating along an X axis at frequency F.
Consider a wave propagating along a Y axis at frequency F.
The amplitude of one is the wavelength of the other.
Hence wavelength IS ALWAYS amplitude for the same F oscillation in a resonant system. For it to be otherwise, you couldn't have resonance.
Postulate A: Mass isn't real
Postulate B: the energy in light is also 'kinetic'
Postulate C: Light bind force must be cyclical
Postulate D: only 2 fundamental particles are possible
Postulate E: the only force is electric
Postulate E2: The binding force (Postulate C) is electric
POSTULATE F: The speed of light is obvious
POSTULATE G: Time is measured in spins
POSTULATE H: All dipoles are equal, matter,even red and blue light
Postulate I1: Donut Particles
Postulate I2: Donut Particles are themselves dipoles
Postulate I3: Anti-particles
Postulate I4: Bigger particles twist and break
Postulate J0: How light binds to matter
Postulate J1: A Slit is a phase sorter
Postulate J2: Gravitational lensing is just diffraction
Postulate J3: Electron is a Donut Sandwich
Postulate J4: Binding force is harmonic electric
Postulate J5: Photons from Electrons
Postulate J6: Wrapped electrons from photon
Postulate K: How fast do forces propagate?
Postulate L: Warp, Time Machine, Light squared computers
Postulate M: The Hydrogen Atom
Postulate M4: 50% matter 50% anti-matter
Postulate M5: Found your Quarks, Leptons, etc. sortof
Postulate N1: Black Holes are 2F universes (we're inside one)
Postulate A: https://science.slashdot.org/comments.pl?sid=12866516&cid=57598384
Postulate B: https://science.slashdot.org/comments.pl?sid=12869268&cid=57599376
Postulate C: https://news.slashdot.org/comments.pl?sid=12870718&cid=57604074
Postulate D: https://hardware.slashdot.org/comments.pl?sid=12877158&cid=57615478
Postulate E & E2: https://hardware.slashdot.org/comments.pl?sid=12877158&cid=57615516
Postulate F: https://hardware.slashdot.org/comments.pl?sid=12877158&cid=57615700
Postulate G: https://hardware.slashdot.org/comments.pl?sid=12877158&cid=57615906
Postulate H: https://hardware.slashdot.org/comments.pl?sid=12877158&cid=57616274
Postulate I1: https://tech.slashdot.org/comments.pl?sid=12881348
Imagine if you had a array of these clocks spread out in a 2d grid, level with each other to within less than a millimeter, It is possible some would run faster or slower than the others because of subterranean variations in density, and thus slightly different amounts of gravity.
Interesting stuff, thanks for sharing.
Isn't this the wrong way round? The clock is correctly measuring local time to a very high accuracy - but local time varies according to gravity, so it's not an accurate measure of time anywhere else.
We've always had the idea that there is only one time, THE time, and it's the same everywhere. Relativity says this isn't true, but we've still stuck with it - as long as you stay on Earth the differences are so small as not to matter. But now we have a clock that's accurate enough to actually detect the differences in time between locations on Earth. If you want to know the time accurately, you need to use a clock in the exact place where you want to know the time, or measure gravity to ridiculous accuracy to get the correction factors for a clock elsewhere.
Not quite. How do you set time of day? It's only a frequency reference, not a time reference. For time references, there's really only GNSS, dialup time services like ACTS and the various radio services (and maybe Iridium). The value of the CSAC, synchronised with GNSS, is that it will give you better holdover than the very ordinary crystal oscillator in your PC if GNSS is unavailable.
As for the frequency offset, the CSACs 'age,' that is their frequency offset increases with time, so that the time offset increases quadratically.
I know you were just joking but ... it's not a clock. It's a frequency reference. A clock needs to run continuously and the state of the art 'clocks' like lattice clocks are not reliable enough to do this yet. Very good frequency references can be used to correct the frequency of less accurate clocks and this is what happens in the computation of Coordinated Universal Time. Time of day is computed from 400 or so continuously running hydrogen masers and caesium beam standards and then a very small correction is made using 'one second' as calculated from half a dozen or so extremely good frequency standards like caesium fountains.
Trying to post as anonymous due to limitations placed on my account. You're using debilitating beautiful mind for connecting dots that are not even dots. What is your definition of "human"? Well. What can i say. It's the times of CIA lemon party gestapo equality regime where even war equals peace, freedom equals slavery, ignorance equals strength, humans equals frankenstein bioweapon program pervertariat inhuman monsters who strangely enough are made to appear as more human than humans they are genociding, etc.. So if you're trying to make sense of something - that can mean lots of things. For starters that you do not have "need to know" security clearance. That something is bothering you. Maybe you're just acting for whatever non state reason. In few days time i'm "participating" on slashdot anonymous free speech e-biz forums - my unlimited free speech already limited to 2 posts per 24 hours period. It's some sort of strange swastika worshiping indochina social karma system. My karma rating is already "terrible". I was awarded two strange cryptic achievements "days read in a row". Sounds like training someone by the name of "day" for the balanced amusement ride in a fair called death row. Don't make mistake about my moniker - it's a lithuanian word that translates into english as "briefly", short amount of time, etc.. So if you want to "friend" me whatever that means you have to ring my doorbell in real life, physically. You know like that matrix movie and drooling retard Neo coming to indulge in aroma of fresh baked cookies at the premises of false oracle. You know it's war on terror waged according to doctrine of "you're with us or with the terrorists". Nobody is with us. It means you're just like everyone else is with beautiful mind terrorists. In this case word "terrorist" is dual use lulzboat. You know it's made from latin word "terra" aka earth. So terrorists are earthlings targeted by all kinds of crazy narrative such as "no country for old men" where cut of age for "oldness" is no child left behind. At the same time as you noticed already the "free speech" is designed with flat earth in mind. You know it's about ears of the uber alles rainbow cloud technology that are flat to any complains. They go around dishing final solution after final solution. Trumping everything they hate with love of trumping. You know in this case word "FINAL" is lulzboat, if letters "F"+"I" is in fact divided letter "A". Try looking at videos of top brass of third reich. Mannerisms, gesticulation, gait, etc.. No wonder they loved those meticulosly planned pride parades so much. So how is it possible for CIA lemon party gestapo to enter the same river twice? Lets not jump ahead of ourselves while crossing dried out riverbeds.
Beautiful man! Did you write the biography?
Now we will FINALLY know what time it really is!
A man with a watch can tell you what time it is.
A man with two watches is never really quite sure.
This new clock demonstrates a sort of high-tech version of this problem. Two of these clocks might not agree because they are in different locations, where gravity is stronger or weaker. At least in this case, the clock can help solve its own problem by helping refine the map that it needs to be more accurate.
Beautiful man! Did you write the biography?
no. i'm not from tar budgets. I can't sing even a simplest melody. You know anything related to so called "arts" is a pride parade territory of so called intelligent community that operate in the shadows camouflaged as intelligentsia. One of their swords for coming is discipline of kung fu hustle for disturbing the peace purposes. In this case it's about surfing the waves of "one eyed is the king in the kingdom of the blind". You know in the kingdom of the blind the kings can roam naked telling tall tales about the talent.