Single-Ion Clock 100 Times More Accurate Than Atomic Clock 169
New submitter labnet writes with this excerpt from news.com.au: "University of New South Wales School of Physics professor Victor Flambaum has found a method of timekeeping nearly 100 times more accurate than the best atomic clocks. By using the orbit of a neutron around an atomic nucleus he says the system stays accurate to within 1/20th of a second over billions of years. Although perhaps not for daily use, the technology could prove valuable in science experiments where chronological accuracy is paramount, Prof Flambaum said."
yeah but (Score:4, Funny)
until it comes with indiglo i don't want it
Eventually... (Score:5, Interesting)
Eventually you'll be so accurate that walking by the thing will cause enough relativistic distortions that you can no longer claim to have any accuracy at all.
Re:Eventually... (Score:5, Funny)
Grr! You changed the clock by observing it!
Damm kids!
Re:Eventually... (Score:5, Funny)
Although perhaps not for daily use, the technology could prove valuable in science experiments where chronological accuracy is paramount, Prof Flambaum said.
As the different series of Star Trek have already shown us, the words "chronological accuracy" and "Paramount" do not belong to the same sentence, much less do they deserve to be joined by the copula.
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Don't forget everyone also has to agree on a where the clock should be as relativistic effects creep in. Put that clock at the equator and compare it to one at one of the poles after a few decades, uh oh!
Re:Eventually... (Score:5, Informative)
Re:Eventually... (Score:5, Funny)
So what you're saying is that by stacking a few dozen alarm clocks on top of each other, I can get one more hour of sleep?
Cool!
Re:Eventually... (Score:5, Funny)
The only flaw in this plan is, that you would need to sleep through all alarms but the last one.
Other than that it's perfect.
Yes.
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Easily solved... just set the last one to go off first.
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It depends on where their timebase is. If you have a clock which receives time/frequency from GPS or WWV*, or the AC power line, for example, it won't matter.
That might bring up the definition of "clock." I supposed one might argue that a clock must be self-contained, but most people would agree that their clocks are clocks, and many are driven by the AC powerline.
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Stacking two clocks on top of each other would cause them to phase lock due to every known experimental defect.
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Moving (Score:2)
No, at least according to Special and general relativity, there is no preferred direction to the universe, and there is no such thing as "absolute still". There's no way to not move in a universe where the space itself is moving as well.
Movement must always be defined in relative terms, since general relativity is background independent.
Similarly, when dealing with particles, there's no "absolute still" since that is the same as absolute zero, which is an asymptotic physical limit to the temperature.
Re:Eventually... (Score:5, Informative)
Re:Eventually... (Score:4, Insightful)
Re:Eventually... (Score:4, Insightful)
a man with three clocks knows if one of his clocks is not working correctly.
So does a man with two clocks. But a man with three clocks may know which one.
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Re:Eventually... (Score:4, Funny)
THERE ARE FOUR CLOCKS! (god, this thread is pedantic torture :)
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A man with three clocks will invariably find some convoluted way of using them to tell the time:
"This one runs ten minutes slow every two hours. This runs twenty minutes fast every four hours. The one in the middle is broken and stopped at two o'clock. I take the ten minutes on this one and subtract it from the twenty minutes on that one. Then I divide by the two in the middle."
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Not if it is digital
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Actually it still will be. Those old VCRs that used to flash 12:00? A stopped digital clock, right twice a day.
Now, if the digital clock is broken, and not merely stopped, such that it cannot display anything, it will never be either right or wrong.
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Not if you're using 24 hour time. Then it's only right once per day.
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I could be wrong but isn't the definition of one second based on some atomic phenomenon? (All the sloshing water and wind makes the revolution of the planet a non-starter...)
How can a new method be more accurate than the method we use to define time?
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Because the measurement used to define time drifts slightly.
The second used to be defined based on the Earth's rotation, but cesium atomic clocks became so much more accurate than the earth itself, that the standard was changed to be based on the behavior of a cesium atom. The standard can always be changed again.
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I could be wrong but isn't the definition of one second based on some atomic phenomenon? (All the sloshing water and wind makes the revolution of the planet a non-starter...)
How can a new method be more accurate than the method we use to define time?
jitter phenomena. Aka phase noise. You'd like to think something like a Rb clock watches exactly one atom and counts that single atom, but its a lot more analog than that.
Man you has one clock knows what time it is, as you say. Man who has two clocks has no freaking idea what time it is. Man who has at least three clocks and lets ntpd or equivalent do its thing for a couple days/weeks has excellent idea what time it is and how accurate each clock is relative to "the group".
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Because the current definition [bipm.org], based on a hyperfine transition of electrons in the Cesium atom, cannot be practically realized. The "definition refers to a caesium atom at rest at a temperature of 0 K." Neither of those conditions can be realized in the real world (there's gravity, and electromagnetic fields, etc.), and corrections are imperfect.
The new method discussed in the article, allows one to realize a better performing
Dual purpose- (Score:2)
at which point will use it for a RND seed generator
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Just scientific experiments? (Score:5, Interesting)
You kidding me? The prospect of GPS-guided bullets accurate to the millimeter will have the US military pursuing this in next-gen GPS satellites as soon as the technology is viable. Hell, this'll be the most valuable update to military hardware in decades.
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You kidding me? The prospect of GPS-guided bullets accurate to the millimeter will have the US military pursuing this in next-gen GPS satellites as soon as the technology is viable. Hell, this'll be the most valuable update to military hardware in decades.
I really don't think the distance a GPS-guided bullet travels will require the additional accuracy provided by this new clock. If your target is moving so fast that you need more accuracy than an atomic clock provides then you shouldn't be using a bullet.
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I think that a laser guided bullet would be more likely to work given that GPS targeting is not so good at hitting moving targets.
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You kidding me? The prospect of GPS-guided bullets accurate to the millimeter ....
Snipe much?
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Have you been watching "Runaway" again?
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I'd have thought that such a "distortion", which would just be relativistic differences, and as such would be somewhat constant or predictable. At the very least, over time they should be able to, estimate the amount of "distortion", which would likely mean they would get more and more accurate over time, as they improve this prediction algorithm. Additionally, if more satellites are added to the field, and perhaps if the protocol also better supported geographically fixed transmitters, you could further el
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The poster above you is wrong - GPS is effected by relativity, but it's a known effect already compensated for. While I suppose we could start talking about rotational frame dragging as well, that's also a well-studied and well understood effect which can be corrected for. Worst case is that a handheld receiver might not have the computational power to handle it, but nothing about relativity fundamentally prevents using GPS.
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Excellent. Thanks for the response. I thought as much.
Re:Just scientific experiments? (Score:5, Interesting)
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For "hyper-precision" you would probably have to account for transportation velocities/times
It's the twin paradox but with microseconds of difference.
Or re-sync them in place which is very complicated to do as well.
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GPS satellites already have to take into account the relativistic effects of their motion. This is not new.
Right now, they "only" meed to take into account relativistic effects due to the satellite's speed, or due to the lower gravity at their altitude. What is new is that this new clock is so sensitive that it would need to take into account the relativistic effects due to the small amount of gravity caused by passing trucks...
The former is easily modelizable (and can thus be compensated for), whereas the later isn't.
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GPS already has to take account of both general and special relativity. It wouldn't be much good if it didn't.
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If I remember correctly, GPS will be difficult to get much more accurate than it is today to the time distortions caused by relativity.
Ionospheric delay is responsible for virtually all inaccuracies that matter in the current system.
With planned upgrades to GPS and or several competing systems from Russia, China and Europe coming online we will soon be able to very accuratly quantify local ionospheric conditions in realtime by looking at how each frequency is effected.
Comment removed (Score:4, Funny)
Link to actual paper (Score:5, Informative)
http://arxiv.org/abs/1110.2490 [arxiv.org]
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Hmm, It looks like the clock isn't as accurate as claimed..
It's based on measuring a single atom of Th229 which has a half life of 7340 years.. So every so often your new fancy ion clock is going to randomly drop dead. (Unless you have multiple units and are comparing the outputs..) Then you need to isolate a steady supply of ionized Th-229 (which is a decay product from U-233, 160KY) to repair the dead modules.
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http://www.nist.gov/public_affairs/releases/aluminum-atomic-clock_092310.cfm [nist.gov]
The Aluminium Atomic Clock seems to be roughly as accurate (1 second every 3.7 billion years, so at worst 1/20th as good as the accuracy claimed in the article) and doesn't seem to use unstable isotopes. For now, at least, I'm going to say the Aluminium Atomic Clock is the way to go for any actual experimental use at that level of precision.
Orbit of neutron around the nucleus? (Score:4, Interesting)
And here I was, thinking that neutrons were inside the nucleus and electrons were orbiting around it. What's going on here? How can a neutron orbit a nucleus? It's an actual question, I know the atomic models I was once taught are way out of date (by a couple of centuries, probably), but I never heard of neutrons orbiting nuclei.
Re:Orbit of neutron around the nucleus? (Score:5, Informative)
Re:Orbit of neutron around the nucleus? (Score:4, Funny)
Thanks a lot. Now I am disturbed. Everybody knows the nucleus is a bunch of little round colored balls globbed together.
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Thanks. I almost puked when I read the word "orbit".
since a neutron is so small (Score:2)
If You Need That Much Accuracy (Score:5, Informative)
It'd be nice if some physics professor *cough* could solve those problems before making some shit that can be accurate for a billion years! See what I did there? That was just passive aggressive right there, wasn't it? Too much Portal, lately...
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It'd be nice if some physics professor *cough* could solve those problems before making some shit that can be accurate for a billion years!
Why would they? Physics professors typically don't care what time it is. They only care about how long it's been since event "X". There is clear evidence for this in how they always seem to come late to class. Damn those leap seconds.
Sadly, I'll never know ... (Score:2)
I can't even get my atomic watch to set properly from the time signal that exists now.
I must be too far from Denver for the signal to get to my watch. Which sucks, since it defeats the whole purpose of having that.
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Your watch is probably doing a rather lame decoding of the signal. Good receivers directly digitize the incoming signal, do filtering and demodulation numerically, and can correlate it with a model signal over minutes or even hours to get a lock. A friend of mine, a real RF nerd, has made such a receiver and it works where you can't even see the damn signal on a spectrum analyzer, with a decent antenna, on the narrowest bandwidth setting (10 or 15Hz IIRC). I think it routinely worked for him when he was sta
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Yeah, I figured that part out. :-P
It's a relatively inexpensive Casio, so it's not like I expected a great amount of technology.
Was just a little bummed that it has rarely (if ever) been able to set from the atomic signal -- that was supposed to be the cool part, and what I could use as a baseline to keep my other watches set correctly.
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I don't know how much help it'd be, but make sure the watch is near a window or, less ideally, the outermost wall, closest to Denver. It should attempt synchronization past midnight CST, when the station has greatest coverage and thus strongest signal. During the day you can pretend the signal is not there, because if that watch can't sync at night, it'll be hopeless during the day.
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Yeah, tried standing in the back yard facing mostly west, but not much luck. But, that was during the day.
Sadly, no window faces the right direction that is helpful here.
Trying to sync after midnight CST (isn't Denver MST?) might help. It's not the end of the world ... it hasn't worked yet. :-P
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Agreed. Sheesh, you'd think they could afford to raise the power of the signal, or add more sites.
How do you measure how accurate it is? (Score:4, Insightful)
If an atomic clock is your most accurate timepiece then how on earth can you tell if something is more accurate?
Can someone explain?
Also , given that a second is defined in terms of the ceasium atom as used in atomic clocks then surely anything that deviates from this is by definition LESS accurate (if you see what I mean)?
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If the accuracy is defined as fractions of a second over billion years - how do they know its going to last a billion years
Re:How do you measure how accurate it is? (Score:4, Insightful)
If the accuracy is defined as fractions of a second over billion years - how do they know its going to last a billion years
Run the reciprocal and test your frequency. You know that saying about how in europe they think hundreds of miles (err KM) is far away and hundreds of years is recent, but in the US they think hundreds of miles is a daily commute and hundreds of years is ancient? Well billions of seconds is a long time, but billions of cycles per second is actually medium to low frequency in the RF world now a days, depending I guess on industry (that would still be considered kind of fast in the PLC/VFD field, but truly ancient great-grandfatherly stuff in the radar world)
So you've got three atomic clocks (now a days a ebay special Rb clock is about $100 surplus) and use that to drive three sets of ham radio microwave experimenters gear at 10 GHz (which is not cutting edge anymore). Hmm. 10 billion hz. suddenly fractional parts per billion becomes fractional hz which a piano tuner has no real problem detecting.
This isn't exactly how it works, but as a thought experiment you hook up your 10gig ethernet and drive it with this clock and hack the driver for variable length packets... If you think you have better than 0.1 ppb clock, then you should be able to transmit a billion bit packet and not fall out of frame sync (which at 10 gigs only takes a tenth of a second). This is not exactly the modulation method used by real 10gigE and not exactly how you test it, but it within the realm of the general idea.
Good luck doing modern ham radio stuff like bouncing microwave signals off the moon using the more exotic low SNR digital modes without at least PPB level frequency accuracy. Freq stability is a factor at 10 GHz until at least 10e-9 for that kind of work... luckily 10e-11 is cheap and off the (ebay) shelf for $200 or so GPSDO or old Rb oscillators.
Re:How do you measure how accurate it is? (Score:4, Insightful)
The same way it always was. Think of how you'd do it in any sort of mechanical measurements. You don't need the same level of accuracy to determine that something is more accurate. Most measurements have nice properties that must hold when you repeat the measurements, such as linearity. All you have to do, then, is to use the assumedly more accurate device to characterize the errors of a less accurate one. If you can reproduce your results and various expected properties hold, then there's no other explanation but that your new device is in fact more accurate.
The deal with the caesium atom is that it only defines a second to a certain accuracy. If you have a better time reference, it's not by definition less accurate, it's just that your standard has accuracy only to so many decimal digits and when you're past that you must get a better standard. You can use the better reference to characterize the inaccuracies in your standard (say various drifts, phase noise in case of time references, etc). Eventually, you redefine the second using the better standard, and you do it pretty much by appending some arbitrarily chosen digits to the new definition that reproduces the old one. They had second defined however, then they measured it using the caesium clock, got a bunch of results, averaged them, and said: that's the new second. A whole bunch of digits of the new definition were pretty arbitrary -- they original definition wasn't able to provide you with stable digits all the way. Same thing will happen again: the new clock will be used to measure the cesium one, and they'll average things and the new second will be a few orders of mangnitude more cycles of this nuclear clock; it will be matching the old clock within the old clock's accuracy, but the now-added digits will be entirely arbitrary. This is how it has happened with pretty much all the other measurements (distance, weight, etc).
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2) As with all the base units, we must 'define' the second in terms of something physical, which we can measure, so that we can use this abstract idea in the real world. This real-world embodiment is imperfect, and it is an engineering challenge to make something which better approximates the idea. For illustration, consider the kilogram, which is defined by a lump of metal in Paris. In principle,
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The most accurate timekeeper is actually a battery of atomic clocks, with an average taken (after all known relativistic distortions are accounted for), called TAI. If your new clock hews to that average better than the individual atomic clocks used to generate that average, it's more accurate.
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Wouldn't an average between all those clocks raise the standard deviation of the (granted) extremely precise measurement?
Wouldn't be better to just use a single clock?
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No, the average of independent measurements has a lower variance [wikipedia.org] than the individual measurements.
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Wow, amazing. I'd expect the average of all those normal curves to result in a fattier normal curve. I'm still wondering if a simple shift in the time axis means they are uncorrelated, though.
I guess I'll have to reread a few books on quality management...
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secÂond 1 (sknd)
n.
1. Abbr. sec.
a. A unit of time equal to one sixtieth of a minute.
b. The time needed for a cesium-133 atom to perform 9,192,631,770 complete oscillations. See Table at measurement.
I can only see this as less accurate!
I have to say (Score:4, Funny)
It's about time
Preprint on arXiv (Score:4, Informative)
A nuclear transition in triply-ionized 229Th has been found which is particularly insensitive to external magnetic fields and electron configuration, which gives the potential for a very stable clock,several orders of magnitude better than current clocks if phase comparisons can be made across a scale of days or weeks. The transition energy is at 163nm (in the ultraviolet). To take advantage of this clock an extremely stable laser at this wavelength (using current best clocks) will need to be created.
How can you tell?? (Score:4, Interesting)
I've always wondered, with regard to the accuracy of clocks like this, how can you actually tell how accurate it is?
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Essentially when they say "clock" what they mean is "stable oscillator" -- they have a source of (in this case) ultraviolet light whose frequency varies hardly at all. Since this is purely theoretical exercise, they are simply calculating how much stray electric and magnetic fields and other problems would be expected to vary the frequency. To check experimentally, I think they'd need two such sources and then see how the relative phase of the light changes over time (after allowing for relativitistic effec
Experimental work and some context (Score:2)
Where is the obligatory FTL neutrino post? (Score:3)
100 times more accurate? (Score:4, Insightful)
If Server A has 90% uptime and Server B has 99% uptime, that does not mean that Server B is up 10x more than Server A, even though Server A is down 10x more than Server B. In fact, Server B is only 10% better than Server A. Or, 1/10 as bad.*
So, while the old clock may drift 100x more than this new one in a certain amount of time, or this new one might last 100x longer before drifting a certain amount (or whatever--the .au article is total puff and I don't care enough to look at the source), it is almost certainly not 100x more accurate. At best, it's 1/100th as inaccurate.
* The difference between 36 days of downtime per year versus 4 days might be the difference between "useful" and "completely worthless", making Server B 100x better, but that's not what we're measuring here.
1st attempt at /. car analogy (Score:2)
It all seems like an unnecessary gain.
Kind of like choosing a car that can reach 210mph over one that can only do 150mph when the national speed limit is only 70mph.
Yes, I know the figures don't show 100x but it just seems that it's pointlessly better than the currrent best clock which is already better than most people would ever need.
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From TFS:
Although perhaps not for daily use, the technology could prove valuable in science experiments where chronological accuracy is paramount, Prof Flambaum said."
This isn't intended for "most people," but for very precise scientific experiments.
Accuracy measure (Score:3)
So, honest question, how do you measure the accuracy of the world's most accurate clock? I mean, what do you measure it against?
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Oh! Great. more FTL now. (Score:2)
Re:Orbit around a nucleus? (Score:4, Insightful)
Re:Orbit around a nucleus? (Score:4, Interesting)
The term "making sense" is, I believe, misapplied here. The quantum world is pretty much unavailable to our senses, neither do they exactly teach this stuff to kindergartners. So we have no early-life experience of any sort here, thus there's no common sense about the world at quantum scale. It won't ever make sense, and there's no reason for it to make any sense. It's just how the world happens to work, and there's nothing at all that we can do about it. This is in stark contrast to, say, bureaucracy, where certain ways of doing stuff are not how Nature works, but how humans happen to work -- very changeable if you can pull it off.
Lack of good quantum analogies: (Score:2)
In the words of david Mermin: "Shut up and calculate!"
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What do you mean by "makes sense?" We can describe the interaction of electrons with other subatomic particles to more-or-less arbitrary precision (better than we can measure in experiments, anyway). There are some subatomic interactions that can be predicted, using QED/QCD, out to 10+ decimal places, and subsequently confirmed by experiment. Clearly the modern physics descri
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I don't see it as a paradox at all. Wave/particle duality invariably involves waves when you're integrating over time and particles when taking instantaneous views. We know from things like quantum tunneling that the particle can exist anywhere along the wave function but we also know that it can only exist at SOME point along the wave function at any given time - it does not exist everywhere.
Heisenberg's Uncertainty Principle is ultimately a property of information theory, not physics, but it helps that pa
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...what is the point of this?
Genuinely. I'm seriously interested. I want to know the kind of science which requires timings of this accuracy. I think they must be some really exciting experiments to be studying phenomena on that short a timescale.
Maybe those guys who thought they measured something traveling faster than the speed of light could use a more accurate clock (not to mention a better plug) ;-)
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A whole lot of science and engineering needs this. We have communication networks that give us ability to distriute experiments and measurements, but a lot of those aren't very useful without a very precise time reference; the networks, as they are, are quite poor at distributing time. Examples: suppose you want to measure time-of-flight of particles across the globe (neutrinos or otherwise); large base telescope (whether radio or optical); more accurate global positioning. The prerequisite in all cases is
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Maybe YOU don't need it, but some of us have real jobs and need to know where to be, down to the femtosecond.
I would have had to wind my old clock in a few hundred million years, but after I get one of these babies, I won't have to.
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Yeah, but do you want to be the guy who has to sit there counting that neutron going past?
A guy could ruin his eyes with that sort of fine work.
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...what is the point of this?
Genuinely. I'm seriously interested. I want to know the kind of science which requires timings of this accuracy. I think they must be some really exciting experiments to be studying phenomena on that short a timescale.
High frequency gravitational waves? I recall reading about this a while ago - i imagine that it requires an exceedingly accurate time reference, since the effect of grav waves is so small.
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No gravitational wave of any frequency has ever been observed.
Indeed - what i mentioned is an experiment to verify their existence. I've looked it up [lnl.infn.it].
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Could, could, could, could. Just a method of timekeeping that *could* be used, but has many issues. How about an post on warp drives next?
New discoveries, breakthroughs and technologies have potential until they are actually used. Once they are used then they need to prove the projections correct. By today's "everything changes so fast it's hard to keep up without a clock that's more accurate than an atomic clock" standards these things aren't new anymore by the time they've been proven useful (or useless).
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Okay sure, no problem.
I installed OS/2 Warp on my hard drive.
Are you happy now?
Re:atomic clock accuracy (Score:5, Interesting)
Yes, because being off by 2 seconds every billion years is something to worry about. I am sick of having to adjust my watch for the inaccuracy of atomic clocks.
a OC-192 fiber line transmits 10 gigs/sec, roughly.
If you stuck one of those "2 secs/gigayear" clocks on each end, instead of regenerating the clock off the line, I think the circuit would lose line sync and drop every:
365*24*60*60 /10 /2 / 6/60/60/24 = every 18.2 days. Bummer.
Lets check. 10 gigabits/sec at 18.2 days is 18.2*24*60*60*10*1e9 is 1.57e16 bits. 2 secs/gigayear is an error rate of 1e9*365*24*60*60/2 is 1.57e16 bits per clock framing failure. Seems likely.
That is why now a days you get your clock off the line instead of internal clocking at each site. In ye olden T-1 era, a clock that good at each CO would mean you'd probably never experience a clock slip between COs in the lifetime of the equipment... Even in ye olden days we internal timed quite a bit (and some of our DEXCS only could do internal, so we had to)