Scientists make startling discovery

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Re: Scientists make startling discovery

Postby Dantriges » Tue Sep 27, 2011 8:20 pm

guess 60 light-nanoseconds is about 18m, which is well within the resolution accuracy of GPS, so accurate distance measurement is unlikely be the problem, but what about the time? Wikipedia claims GPS can get you about 10ns accuracy on a time reading, which still seems like a lot of uncertainty on a 60ns measurement. Is clock sync done some other way, like by physically taking your atomic clock from one location to the other (at a non-relativistic speed to avoid time dilation)?


One of the articles linked has some stuff they used to measure time and distance.

Details, details

"These are experiments where the devil is in the details – the details of how each piece of equipment works, and how it all goes together," said Rob Plunkett of Fermilab in Batavia, Illinois.

The detector in the Gran Sasso cavern is located 1400 metres underground. At that depth Earth's crust shields OPERA (which stands for Oscillation Project with Emulsion-tRacking Apparatus) from noise-inducing cosmic rays, but also obscures its exact latitude and longitude. To pinpoint its position precisely, the researchers stopped traffic in one lane of a 10-kilometre long highway tunnel for a week to place GPS receivers on either side.

The GPS measurements, which were so accurate they could detect the crawling drift of the planet's tectonic plates, gave precise benchmarks for each side of the tunnel, allowing the researchers to triangulate the underground detector's position in the planet. Combining that with the known position of the neutrino source at CERN gave a distance of 730,534.61 metres, plus or minus 20 centimetres.

To determine exactly when the neutrinos left CERN and arrived at Gran Sasso, the team hooked both detectors to caesium clocks, which can measure time to an accuracy of one second in about 30 million years. That linked the labs' timekeepers to within one nanosecond.

"These kinds of techniques that we have been using are maybe unusual in high energy physics, but they are quite standard in metrology," Autiero said. Just to be sure, the collaboration had two independent metrology teams from Switzerland and Germany check their work. It all checked out.

The researchers also accounted for an odd feature of general relativity in which clocks at different heights keep different times.
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Re: Scientists make startling discovery

Postby rodos » Tue Sep 27, 2011 10:41 pm

Dantriges, reading articles so I don't have to.
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Re: Scientists make startling discovery

Postby masterpoobaa » Thu Sep 29, 2011 4:14 pm

I love it when scientists do these sort of things. So much tiny detail and amazing precision that the average joe-slob public has no clue about :)

I have a science degree and consider myself quite geeky - But even I had forgotten that clocks at different altitudes count time differently due to the spin of the earth, rotational velocity and laws of relativity.
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Re: Scientists make startling discovery

Postby aureon » Mon Oct 03, 2011 7:34 am

Any iterations on the subject yet?
Was the error found?
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Re: Scientists make startling discovery

Postby Ruex » Tue Oct 04, 2011 6:00 pm

aureon wrote:Was the error found?

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Re: Scientists make startling discovery

Postby degre » Sat Oct 15, 2011 5:09 pm

aureon wrote:Any iterations on the subject yet?
Was the error found?

Mystery solved.
http://dvice.com/archives/2011/10/speedy-neutrino.php

tl;dr
They didn't take into account earth rotation, hence the distance between the two points is the one they took into factor, while the distance actually travelled is different.
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Re: Scientists make startling discovery

Postby Klaudandus » Sat Oct 15, 2011 5:43 pm

That's good, cuz otherwise, we could have ended up with this.

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Re: Scientists make startling discovery

Postby RedAces » Mon Oct 17, 2011 10:36 am

This explanation is wrong, (german) source: http://www.heise.de/newsticker/meldung/ ... 62506.html
They used a system namend "common view" which accounts for all that PLUS he made an error in his formulas:

"Dr. Feldmann fand außerdem auch gleich einen Fehler in der Arbeit von van Elburg. In Gleichung (2) werden einfach Satelliten- und Signalgeschwindigkeit klassisch statt relativistisch aufaddiert."

Translated: In equation (2) he added the satellite and the signal velocity classically (?) and not relativistic.
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Re: Scientists make startling discovery

Postby theckhd » Mon Oct 17, 2011 11:51 am

The BadAstronomy guy also had some commentary on this. The earth rotation theory doesn't pan out, and I've read in several places that the Feldmann explanation was wrong as well.
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Re: Scientists make startling discovery

Postby Arcand » Wed Oct 19, 2011 12:03 pm

So does that mean...

a) the neutrino travel-time discrepancy is resolved, but the explanations of its resolution aren't accurate, or

b) the supposed resolutions of the neutrino travel-time discrepancy aren't actually valid?
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Re: Scientists make startling discovery

Postby theckhd » Wed Oct 19, 2011 12:09 pm

b)

We still don't have a good explanation for it yet.
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Re: Scientists make startling discovery

Postby Dantriges » Wed Oct 19, 2011 4:01 pm

The subspace comm hidden in the pyramid by the Atlanteans was receiving messages to prepare the doomsday machine for 2012 and ordering local assets to leave in time taking fellow human allies and alien intelligence personnel with them. The distortion affected the CERN experiment and resulted in the discrepancies. :D

If I am fast I can make a buck by publishing a book with the story. :wink:
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Re: Scientists make startling discovery

Postby Invisusira » Wed Oct 19, 2011 4:38 pm

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Re: Scientists make startling discovery

Postby Passionario » Mon Oct 24, 2011 5:13 am

If you are not the flame, you're the fuel.
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Re: Scientists make startling discovery

Postby Klaudandus » Wed Nov 02, 2011 11:41 am

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