Popcorn and beer for this one.

Try is the best I can do, as I said I am not a physicist...if you find that entertaining so be it. But my thought is - How would you ever learn anything if you are not willing to try and put effort toward it? In the very least I hope to have a discussion with my friend's father who is a chemistry prof, manages a large NMR machine and such.

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TC
Current stable:
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- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

Also take "criticism" with a grain of salt...I basically just want to glean how they calibrated this thing and a basic understanding of how they measured it, both of which should be outlined in the methodology.

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

I meant absolutely no disrespect and apologize to you if it came across that way.

To the contrary, and for the reason you wrote, I am very respectful of your effort.

I was hoping the (failed) analogy would work like this: I watch a sport on TV. I make popcorn and watch in admiration and hope for a certain outcome. I fully recognize that the player competence far exceeds mine.

B

Thanks bot I owe you an apology - I woke up on the wrong side of the bed this morning (literally) after an awful night's sleep and read that in the worst of moods, i see what you actually meant now. The grump meter has gone substantially down now but sorry for that!

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TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

I've been able to dissect this piece a bit today. Here is what I can gather in terms of the way in which it was measured and calibrated. This article is surprisingly accessible, I don't think it is beyond most of us on the forum (granted, I am of the opinion that most folks on here are highly capable both critically and linguistically).

They used a hypersensitive GPS system to determine the exact spatial distance from A to B (730km). They state in the article that "timing upgrades" have been able to reduce the amount of error to statistical accuracy.

Initially, a stream of photons are generated through a super synchron (do not know what that is, except it generates protons). They are spit out through an extremely strong kicker magnet, and aimed at a large mass of graphite that when hit with these highly charged protons, creates mesons (basically an unstable alliance of quarks and antiquarks, to my understanding) which by nature quickly decay into neutrinos in a vacuum tube. From there, the neutrinos travel 730km to the OPERA detector where they can measure time and thus speed given the constant variable of distance. Here's the important part--because of the ultra sensitive GPS system paired with their timing "upgrades" they essentially synchronize in advance the charge of the kicker magnet with the receiver, so it sends the "release" signal at the exact same time from the same source. The timer itself is calibrated through a beam current transformer, and as described in relation to which the synchronization occurs:

"toroidal transformers coaxial to the proton beam providing a signal proportional to the beam current instantaneously transiting through it, with a few hundred MHz bandwidth. The start of the digitisation window of the WFD is triggered as well by the magnet kicker signal. The waveforms recorded for each extraction by the WFD are stamped with the UTC and stored in the CNGS database," (OPERA collaboration: Adams et.al. 5)

This is as far as I've gotten today

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TC
Current stable:
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Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

That is consistent with what I read last week.

They can find no source of error and are puzzled.

I'm betting it's the GPS timing signal. Educated guess.

Hard to tell. The problem is when you get to such tolerances you have to account for properly anal stuff like the time it takes for the electronic signal to pass through the circuits of the computer. They do have a section on all this in the paper but I haven't gotten to it yet.

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TC
Current stable:
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- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

I use GPS in surveying for some research (not on research on GPS, GPS is a tool used in the research) and have had to deal with time signals and relative geodetic positioning. Just the atmospheric corrections alone have a lot of slop hidden in them. And the shift from absolute position to relative position has assumptions about the geoid, and gravity varies with position and the magnetic field varies chaotically over small time intervals and short distances, etc. On the other hand, why would the results be consistently biased in one direction? That is very curious.

My educated guess is that a bunch of particle physicist are crackerjack mathematicians and accept the GPS values that the EEs and geodesists hand them with less skepticism than they would greet data generated from their own field.

But it would be stunningly cool if the readings are indeed correct. Which is my personal hope and bias.

Since the other thread broke down a bit over vacuum or media, there's a good summary of the construction of decay tube.

Calling long distance: Geneva to Italy - CERN Courier

Installation of the decay vacuum tube began on 18 November 2003. Once the initial difficulties had been overcome, it took 24 hours to complete each 18 m section. The full installation was finished on 16 March 2004, and on 1 April the tube was closed ready for pumping down and vacuum testing. The tube sleeves had arrived rusty and humid, but with the aid of a ventilation system, by the time of pumping down the tube was dry, if still rusty. It was then evacuated to less than 1 mbar, sealed and monitored continuously for 10 days. Throughout the test period the pressure remained stable, never exceeding 1.3 mbar. Such a good result was a pleasant surprise: the tube walls must be smoother than expected with very little absorption of water or gas as virtually no outgassing was observed.


Vacuum test

Completing the vacuum volume are the entrance and exit windows, designed and built at CERN. For the central part of the entrance window, where beam interactions must be kept to a minimum, a 3 mm thick titanium window with a diameter of 1.45 m will be used, somewhat larger than the useful beam size at this point. This is currently being built, for installation in January 2006, so a temporary window of 50 mm steel has been installed for the vacuum tests. At the far end of the decay volume, where losses due to interactions are not so critical, a 50 mm thick steel window has been chosen and installed.

I used to teach some GPS theory, and the "slop" is actually less than you'd expect. Precise time is available on the order of picoseconds. The paper spends some time discussing the methodology and equipment used.

The advertised GPS spec is +/-100 ns, but GPS routinely beats that. There are also functions of stability over time: less accurate over longer time, more accurate over short periods. It's discussed briefly here:

http://ilrs.gsfc.nasa.gov/docs/timing/gpsrole.pdf

The precise time user may require the time tagging of events to the 100-nanosecond level and
maintenance of that accuracy over periods from seconds to years. Modern digital communication
networks use time intervals to maintain synchronization between transmitter and receiver clocks so
that data frame buffers at the receiver can maintain frame alignment with infrequent "slips"
requiring retransmission of the data frame. These users are not affected by pulse-to-pulse jitter
(phase noise) on the order of one nanosecond, but they do require that the time intervals maintain
a long-term phase stability.
Precise frequency users require short-term phase stability but may not require long-term phase
synchronization. Radar and microwave communication systems multiply 5- or 10-megahertz
frequency standards up into the gigahertz regions of the spectrum. Any phase noise from the
frequency standard is multiplied along with the fundamental frequency and appears as noise in the
microwave carrier. Precise frequency users may require time interval signals with phase noise on
the order of one picosecond (10-12 or one trillionth of a second) to maintain sufficient spectral

purity and low noise in their transmitted signals.

A potential flaw in the results may be the reliance on GPS as the measurement tool for both distance and time. Assuming GLONASS has similar precision capabilities and receivers are available, could the same results be achieved using a different stopwatch or yardstick?

FWIW I was hanging out with one of my good friends who is a defense contractor very involved in this sort of thing(details prohibited ) and he mentioned that the GPS positioning for this particular experiment was initially skewed by tectonic plate shift I would call that accurate. Again I haven't gotten to that part of the article yet and I have about 300 pages a week to read for my normal academic workload. BTW thanks guys for keeping this conversation mature and to the point. I continue to be glued to your responses and thoughts on this study

__________________
TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth

I'm just learning about RTK surveying and have never actually done any precision surveying with GPS. Back when I was a real surveyor we used metal tape and a transit (more akin to George Washington's method than anything modern).

I understand that the timing signals are excellent.

Just speculating here...

I hate to mention this topic, but the speed of light changes in the media through which it passes. The atmospheric conditions during any given instant will likely change in the next instant. Certainly between epochs. Especially in a mountainous areas where atmospheric conditions are likely to be turbulent, chaotic and ill-defined by atmospheric sounding models.

How fast does light travel in in turbulent air of varying humidity, density, and temperature?

On the other hand (I have lots of other hands), we must have a non-random source of bias since the readings seem to err predominantly in one direction.

What if there's a dense, massive unknown ore body that causes a local gravity difference? Oh well, they probably have gravimetric and magnetic maps of the area, so that's probably not it.

Maybe a sperm whale and a flower blossom materialized overhead.

A shift in a tectonic plate, or magma, or some subsurface phenomenon can affect the time signals. Changes in the earth can affect the gravitational pull which affect the orbits slightly. This affects the time delays. They update the ephemeris data to compensate. These are tiny changes but the precision needed is tiny.

Changes or variations in the ionosphere can also induce errors of approx 10 m or 30 - 40 ns.

Am I suggesting this occurred? No, but they are some of the variables that will need to be considered and eliminated as sources of error. But a persistent bias in one direction across months of testing would tend to argue against the undetected or uncompensated for effects of GPS error.

The whale and the flower pot? Oh no, not again.