[time-nuts] Those pesky Neutrinos again...

[mike cook]

Le 21/11/2011 09:49, Hal Murray a écrit :
> michael.cook at sfr.fr said:
>> I heard on the BBC the other day that a repeat experiment is planned,
>> firing neurinos from the US into Canada. The labs were not cited, but I
>> expect it would be Fermilab  to Sudbury Ontario. If this is the case,  then
>> there will still be the problem of not being able to run a parallel  fibre
>> as the Sudbury detectors are  also deep underground. ...
> I don't think that running a parallel fiber will help much.  I see two
> problems.
>
> First, fibers don't run in straight lines.  Even if you could accurately
> survey the pipes in the ground, there is slack in the fiber within the cable
> bundle so it doesn't break if somebody pulls on the cable.
>
> Second, the speed of light in fibers isn't known to the required level of
> accuracy.  (It's probably temperature dependent.)
>
I was thinking more of using fibre  for determining the distance by 
another method rather than for comparing the time of flight,  and being 
better than 18m  over 740km would stretch the technology .