The paradox is that it’s both disappointing and encouraging. It’s nice to live in an age where something so fundamental can be explored and understood. That’s some pretty precise measuring they’re doing.
the gps satellites also had to give a nod to einstein.
Pity. Stuck with the same old speed limit 🙁
The commentariat at the link you provide would seem to disagree with your judgement. The argument seems to be that the supposed GPS induced error isn’t possible since both “ends” of the experiment were stationary relative to the GPS satelite and that there was at least one ground-based atomic clock used as an independent check of the GPS time sinc mechanism in the initial experiment.
As nearly as I can make out, if the two separate time measurements (GPS + surface-based atomic clocks) resulted in the same outcome published (+ 60ns) then the proposed GPS-based objection is false.
It’s all well beyond my meager talents, but still interesting to observe the process all the same.
“(GPS + surface-based atomic clocks)resulted in the same outcome published (+ 60ns) then the proposed GPS-based objection is false.”
if you use gps you gotta include relativity.
It does seem like kind of a boneheaded oversight, since even the GPS on the dashboard of my truck takes it into account — or is it that the satellites’ own onboard clocks are running at an altered rate to match surface time? One of the two.
Relativity should have already been accounted for by default.
Any commercial GPS unit automatically takes the relative motion of the GPS satellites into account; they simply won’t work if you don’t account for relativity.
And these are the guys proposing the creation of mini black holes, with assurances that the little buggers won’t get away on them and consume the Earth.
I was pretty sure they had a measurement error, and seeing Rand’s blog entry this morning confirmed it. Then Will Brown’s comment alerted me that the explanation offered might be invalid, so I did some quick calculations.
The error was 18 meters across 732 kilometers (18 feet over 454 miles), one part in 40,666, or 2.46e-5.
The neutrino probably passed mostly through granite, and granite is mostly silica (SiO2).
Silica has a molecular weight of 60 and a density of 2.648 g/cm^3, so a cubic centimeter of siilica contains 2.648/60 moles (0.04413) moles.
Multiplying by Avogadro’s number (6.022e23), there are 2.6577e22 molecules of silica in 1 cubic centimeter, so there are 2.6577e28 molecules of silica in a cubic meter.
The radius of an atomic nucleus is 1.2 to 1.5 femtometers (1e-15m) times the cube root of the atomic mass. The average of 1.2 and 1.5 is 1.35, which is what I’ll use.
So, the radius of a silicon nucleus is about 4.1 femtometers (fm), the radius of an oxygen nucleus is about 3.4 femtometers (fm), the volume of a silicon nucleus is about 2.88e-43 cubic meters, the volume of an oxygen nucleus is about 1.65e-43 cubic meters, and the volume of the nuclei of a silica molecule is about 6.17e-43 cubic meters.
Going back to Avogadro’s number above, the volume of all the silica nuclei in a cubic meter of silica is 1.64e-14 cubic meters.
As a cube, the length is 2.5e-5 meters on a side, the path length through the nuclei versus free space.
The error was 2.46e-5
So perhaps neutrinos don’t travel directly through an atomic nucleus, they quantum jump to the other side, like spooky action at a distance.
On the other hand, the little cube I proposed doesn’t work for path lengths and travel. A beam would only hit a nucleus cube about 6e-10 times per cube (it’s a target area thing), and only then would it be slowed down by the 2.4e-5 in that same cube.
But there are some other bizarre experiments with FTL involving EM waves through solids that made this a fair guess, and since interstellar space is so empty, supernova photon versus neutrino emissions wouldn’t provide a benchmark for the effect, as visible light doesn’t travel well through a millimeter of rock, much less 450 miles of it.
Perhaps the problem is that now doesn’t exist? Everything we consider to be now is actually in the past because distance is always involved even if it’s just the distance a thought has to travel in your head. How do you synchronize something that doesn’t exist? Entanglement?
Gps already adjusts for relativity.
This is easy to explain!!
.
.
“The experiment, known as OPERA, found that the particles produced at CERN near Geneva arrived at the Gran Sasso Laboratory in Italy some 60 nanoseconds earlier than the speed of light allows.”
.
.
It’s easy. The particles leave Italy headed to Switzerland in THIS!
What? The particle went the other way? From Cern, TOWARD Italy.
There’s only one explanation then. It must have been some kind measurement error. The Swiss don’t build anything faster than that Bugatti. Clocks and chocolate will never be faster than a Bugatti. Better tasting maybe, but not faster.
Not so fast. I just read the explanation and I have some qualms about it. The claim is that the GPS satellite motion, moving east to west, results in a time dialation via special relativity. But the GPS satellite clocks take into account both corrections from special and general relativity. (BTW, the gravitational effect is larger). Also, the measurements have been going on for some time with other neutrinos which were not superliminal, so why does this effect only show up now? Finally, the clocks at each end of the experiment are commercial cesium clocks which would be updated from GPS with a long period time constant, not instantaneously. This doesn’t mean that a mistake wasn’t made in timing, but I would be surprised if the mistake was one of omission of a physical effect and not one of equipment or human failure with the equipment.
ADD: forgot the reason I was going to post in the first place. GPS sats use 3 satellite planes and it is unlikely that only those sats moving east to west would be been used to update the experiment clocks – most likely some ensemble calculation.
Those neutrinos are still faster than the USS Excelsior.
I read the van Elburg paper. I am skeptical that this is the correct explanation for the OPERA results. I am in good agreement with Chad Orzel’s takedown.
I’m still skeptical of the OPERA results. But this isn’t the explanation. Hyperlinked hype.
Wow, people just can’t wait for science to happen. This paper hasn’t even been published yet. Sheesh.
Hate to burst your bubble, Rand.
Cesium clocks were used for the timing. The clocks were synchronized in the usual way, by hand-carrying a portable clock from one location to the other.
The GPS was only used to verify that there was no drift between the two clocks (generator and detector). No relativity is involved in the original synchronization.
Also, at least 3 GPS satellites are overhead at any given time, so relativistic effects MUST be compensated for in order to coordinate the received signals.
Sorry.
What “bubble” of “mine” do you imagine that you’re bursting?
The paradox is that it’s both disappointing and encouraging. It’s nice to live in an age where something so fundamental can be explored and understood. That’s some pretty precise measuring they’re doing.
the gps satellites also had to give a nod to einstein.
Pity. Stuck with the same old speed limit 🙁
The commentariat at the link you provide would seem to disagree with your judgement. The argument seems to be that the supposed GPS induced error isn’t possible since both “ends” of the experiment were stationary relative to the GPS satelite and that there was at least one ground-based atomic clock used as an independent check of the GPS time sinc mechanism in the initial experiment.
As nearly as I can make out, if the two separate time measurements (GPS + surface-based atomic clocks) resulted in the same outcome published (+ 60ns) then the proposed GPS-based objection is false.
It’s all well beyond my meager talents, but still interesting to observe the process all the same.
“(GPS + surface-based atomic clocks)resulted in the same outcome published (+ 60ns) then the proposed GPS-based objection is false.”
if you use gps you gotta include relativity.
It does seem like kind of a boneheaded oversight, since even the GPS on the dashboard of my truck takes it into account — or is it that the satellites’ own onboard clocks are running at an altered rate to match surface time? One of the two.
Relativity should have already been accounted for by default.
As predicted by XKCD two weeks ago:
http://xkcd.com/955/
🙂
Any commercial GPS unit automatically takes the relative motion of the GPS satellites into account; they simply won’t work if you don’t account for relativity.
And these are the guys proposing the creation of mini black holes, with assurances that the little buggers won’t get away on them and consume the Earth.
I was pretty sure they had a measurement error, and seeing Rand’s blog entry this morning confirmed it. Then Will Brown’s comment alerted me that the explanation offered might be invalid, so I did some quick calculations.
The error was 18 meters across 732 kilometers (18 feet over 454 miles), one part in 40,666, or 2.46e-5.
The neutrino probably passed mostly through granite, and granite is mostly silica (SiO2).
Silica has a molecular weight of 60 and a density of 2.648 g/cm^3, so a cubic centimeter of siilica contains 2.648/60 moles (0.04413) moles.
Multiplying by Avogadro’s number (6.022e23), there are 2.6577e22 molecules of silica in 1 cubic centimeter, so there are 2.6577e28 molecules of silica in a cubic meter.
The radius of an atomic nucleus is 1.2 to 1.5 femtometers (1e-15m) times the cube root of the atomic mass. The average of 1.2 and 1.5 is 1.35, which is what I’ll use.
So, the radius of a silicon nucleus is about 4.1 femtometers (fm), the radius of an oxygen nucleus is about 3.4 femtometers (fm), the volume of a silicon nucleus is about 2.88e-43 cubic meters, the volume of an oxygen nucleus is about 1.65e-43 cubic meters, and the volume of the nuclei of a silica molecule is about 6.17e-43 cubic meters.
Going back to Avogadro’s number above, the volume of all the silica nuclei in a cubic meter of silica is 1.64e-14 cubic meters.
As a cube, the length is 2.5e-5 meters on a side, the path length through the nuclei versus free space.
The error was 2.46e-5
So perhaps neutrinos don’t travel directly through an atomic nucleus, they quantum jump to the other side, like spooky action at a distance.
On the other hand, the little cube I proposed doesn’t work for path lengths and travel. A beam would only hit a nucleus cube about 6e-10 times per cube (it’s a target area thing), and only then would it be slowed down by the 2.4e-5 in that same cube.
But there are some other bizarre experiments with FTL involving EM waves through solids that made this a fair guess, and since interstellar space is so empty, supernova photon versus neutrino emissions wouldn’t provide a benchmark for the effect, as visible light doesn’t travel well through a millimeter of rock, much less 450 miles of it.
Perhaps the problem is that now doesn’t exist? Everything we consider to be now is actually in the past because distance is always involved even if it’s just the distance a thought has to travel in your head. How do you synchronize something that doesn’t exist? Entanglement?
Gps already adjusts for relativity.
This is easy to explain!!
.
.
“The experiment, known as OPERA, found that the particles produced at CERN near Geneva arrived at the Gran Sasso Laboratory in Italy some 60 nanoseconds earlier than the speed of light allows.”
.
.
It’s easy. The particles leave Italy headed to Switzerland in THIS!
What? The particle went the other way? From Cern, TOWARD Italy.
There’s only one explanation then. It must have been some kind measurement error. The Swiss don’t build anything faster than that Bugatti. Clocks and chocolate will never be faster than a Bugatti. Better tasting maybe, but not faster.
From Switzerland to Italy is downhill.
http://twentytwowords.com/2011/10/14/the-greatest-abstract-for-a-journal-article-ever/
Not so fast. I just read the explanation and I have some qualms about it. The claim is that the GPS satellite motion, moving east to west, results in a time dialation via special relativity. But the GPS satellite clocks take into account both corrections from special and general relativity. (BTW, the gravitational effect is larger). Also, the measurements have been going on for some time with other neutrinos which were not superliminal, so why does this effect only show up now? Finally, the clocks at each end of the experiment are commercial cesium clocks which would be updated from GPS with a long period time constant, not instantaneously. This doesn’t mean that a mistake wasn’t made in timing, but I would be surprised if the mistake was one of omission of a physical effect and not one of equipment or human failure with the equipment.
ADD: forgot the reason I was going to post in the first place. GPS sats use 3 satellite planes and it is unlikely that only those sats moving east to west would be been used to update the experiment clocks – most likely some ensemble calculation.
Those neutrinos are still faster than the USS Excelsior.
http://www.youtube.com/watch?v=rRf1zI2IoWQ
I read the van Elburg paper. I am skeptical that this is the correct explanation for the OPERA results. I am in good agreement with Chad Orzel’s takedown.
I’m still skeptical of the OPERA results. But this isn’t the explanation. Hyperlinked hype.
Wow, people just can’t wait for science to happen. This paper hasn’t even been published yet. Sheesh.
Hate to burst your bubble, Rand.
Cesium clocks were used for the timing. The clocks were synchronized in the usual way, by hand-carrying a portable clock from one location to the other.
The GPS was only used to verify that there was no drift between the two clocks (generator and detector). No relativity is involved in the original synchronization.
Also, at least 3 GPS satellites are overhead at any given time, so relativistic effects MUST be compensated for in order to coordinate the received signals.
Sorry.
What “bubble” of “mine” do you imagine that you’re bursting?