[ExI] Faster than light??

Anders Sandberg anders at aleph.se
Fri Sep 23 22:11:41 UTC 2011

john clark wrote:
> On *Fri, 9/23/11, BillK /<pharos at gmail.com>/* wrote:
>     "Ethan Siegel points out that the experiment has already been done
>     on a
>     far larger scale and found no FTL effect."
> Well yeah, if the neutrinos from the 1987 supernova moved as fast as 
> the ones in this new experiment they would have arrived on Earth in 
> 1982, 5 years before the light did, but that didn't happen. However 
> (and I'm just playing devils advocate here) its possible that 
> supernova neutrinos were ultra powerful and so moved just an 
> infinitesimal amount faster than light, but the man made neutrinos 
> were much less energetic and so moved much faster.

The energy of the neutrinos from SN 1987 was measured, and was 10-20 MeV 
if I understand the papers right. So that would mean a squared neutrino 
mass of around -2*10^-66 kg if one were to assume the real reason of the 
early arrival was FTL and not shockwave delay.

The CNGS beam had an average energy of 17 GeV (!). So it had more 
energetic neutrinos that ought to travel slower if they were tachyons. 
But they had a velocity of around 3 times the speed of light! The 
squared mass ends up as -10^50 kg. So either we know nothing about 
neutrino types, or these results indicate a mistake somewhere.

According to my friend at super-kamiokande, nobody over there believes 
the new results are due to FTL, but they are all excited anyway since if 
it *were* true they would be right at the hottest field ever...

(I'm happy I wore my CERN sweater to work today. And XKCD said it best: 
http://xkcd.com/955/ )

Anders Sandberg,
Future of Humanity Institute 
James Martin 21st Century School 
Philosophy Faculty 
Oxford University 

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