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Old 09-27-2011, 01:44 PM   #417
Is not Persian
Join Date: Apr 2003
Location: Approximately La Crescenta, CA
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Originally Posted by ride365 View Post
I don't think this has been pointed out in this thread yet, but the CERN results don't necessarily discount Eintsein's theories or theoretical speed limit "c". It could just mean that we've measured the speed of light wrong or that it was incorrect to assume that c=speedoflight. These results could be confirmed, and the theortical "c" could still hold, and einstein's theories would still hold too.
That could be true, but there is no reason to believe that all of the measurements of c up until now have been incorrect. It's known to a very high precision.

Originally Posted by cowmoo32 View Post
The only problem with that (I think, someone correct me if I'm wrong here) is that we've used E=mc2 in calculations for nuclear reactions for years now and the math works. We know how much energy a given amount of mass has using c=3e8m/s. If c were to change that would mean the energy would change and our calculations have been wrong and we've been extremely lucky that something hasn't gone terribly wrong.
That's sort of correct, but I believe they used the known c to derive the value of m converted to energy.

Originally Posted by BeRzErKaS View Post
I think the recent quakes shifted the earth's tactonic plates and threw off the GPS measurements. Large quakes have also been known to shift the axis of the Earth slightly.

Wake me up when someone proves me right.
Yes, the recent quakes did shift the plates, and they show this shift in their data (7 cm difference from before and after the L'Aquila earthquake two years ago).

Originally Posted by BeRzErKaS View Post
Assuming they know the distance could be the mistake.

They are firing neutrinos through the content of the Earth from Switzerland to Italy. Not through a pipeline of specific distance. They use GPS to measure the distance between the two facilities. With GPS comes uncertainty from various sources. lol...I just threw earthquakes out there as one possible cause.

They are doing a time vs distance calculation to find speed. So either time was altered, or the speed of light was eclipsed, or someone d1cked up the distance measurement. I'm leaning towards option C.
They claim they know the distance to within a few cm.

Originally Posted by cowmoo32 View Post
I must have missed something then. I was under the impression this was done IN the accelerator. If someone screwed the calculations, they did it 15000 times over. The team has tested and retested to be sure of the results.
As mentioned above, the experiment sends neutrinos from CERN in Geneva to the Gran Sasso lab in Italy, but saying they made the mistake 15,000 isn't really accurate. They only have to make 1 mistake in their data analysis and it will be applied to all 15,000 events.

Originally Posted by BeRzErKaS View Post
Just gettin my passline bet in early. They can mail me my PhD later.

...and it wasn't 15000 repeats.

The average speed was found to exceed [what should be] the speed of light by a few fractions of a second. That means some measurements came in high and some low.

Let's not go handing out any Nobel prizes until we at least get a look at the standard deviation of the measurements.
The results are 6 sigma (standard deviations) away from the expected result. That's pretty far from the expectation and constitutes a "discovery" in most cases. Then again, this is assuming they know their systematic errors well.

Originally Posted by pez319 View Post
How do they know that the neutrinos they're detecting are from their test. There's millions of neutrinos flying through us right now and they don't really interact with matter. Maybe unique energy signature?
They know exactly when the neutrinos are fired and only accept events coming within a few ms before and after the expected arrival time. Then theirs the energy signature (I believe also mentioned before) and a muon veto to reject events that are due to muon interactions.

The results are interesting but I'm still skeptical. They say that the neutrinos arrive 60 ns early. If this is an error in their distance measurement, the distance should be off by ~60 ft to account for it, much larger than their claimed precision on the distance measurement. My guess is there is an error in the timing (although I didn't spend much time looking into how they establish the timing) or a problem in the data analysis.

The neutrinos come in large bunches with a finite time spread. They can't say exactly when the neutrino they detected left the accelerator, but they have a probability density function for that time. They have to do some clever analysis to get the time difference, and they use a maximum likelihood method (again, I didn't look much into it). Either way, the problem might lie here. It would be interesting to see what other groups have to say about the data.

Last edited by my ass; Yesterday at 11:15 PM.
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