On 29 Set, 13:39, marco <251aria..._at_gmail.com> wrote:
> mi sembra che anni fa siano stati rilevati dei neutrini provenienti da
> una nova con qualche giorno di anticipo rispetto alla luce della nova
> stessa
>
> la spiegazione del tempo era che i fotoni venivano emessi in ritardo
> perche' assorbiti e riemessi piu' volte, sottointendento che poi
> neutrini e fotoni avessero fatto il viaggio alla stessa velocita'
>
> mi hanno detto che la distanza di quella nova era tale che, con la
> velocita' misurata al Gran Sasso, i neutrini sarebbero dovuti arrivare
> con anni di anticipo, altro che qualche giorno...
>
> qualcuno puo' confermare o smentire?
si, � riportato sulla pagina in inglese di wikipedia
http://en.wikipedia.org/wiki/Neutrino
In September 2011 the OPERA collaboration released calculations
showing velocities of 17-GeV and 28-GeV neutrinos exceeding the speed
of light in their experiments.[29][30][31] The authors write, "Despite
the large significance of the measurement reported here and the
stability of the analysis, the potentially great impact of the result
motivates the continuation of our studies in order to investigate
possible still unknown systematic effects that could explain the
observed anomaly."[29][30] This result had not been detected by
previous experiments, and lies in contrast to several others. For
instance, photons and neutrinos from SN 1987A were observed to have an
agreement in transit time to about 1 part in 450 million, with even
this difference being accounted for by light being impeded by the
material of the star early in its journey. The OPERA results, in
contrast, suggested that neutrinos were traveling faster than light by
a factor of 1 in 40,000,[nb 4] i.e. that neutrino speed is
1.0000248(28) c. Had neutrinos from SN 1987A traveled faster than
light by this factor, they would have arrived at Earth several years
before the photons; this was not observed to be the case.[nb 5][32]
However, neutrinos from the supernova had orders of magnitude less
energy than the neutrinos observed in the OPERA experiment, as the
authors point out.
Received on Thu Sep 29 2011 - 16:28:56 CEST