# The Opera Neutrino Experiment and the Supernova 1987

So this probably stems from my massive ignorance about post-Newtonian physics but the supernova results of 1987 which measured neutrinos arriving 3 hours before the light from the supernova have been presented as a non-trivial objection to the Opera result.

However if the Opera result is confirmed, then doesn't that weaken the supernova objection since star mechanics relies heavily on relativity and such a result might imply that relativity is not the complete picture which in turn could imply different star mechanics than the one we understand?

Thanks

Edit: To clarify, I'm asking whether the supernova objection may not apply given that this experiment seems to challenge relativity which is what has been used to understand the behavior of stars, supernovae and such.

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I'm not an expert in stellar physics by any means, but I can say this: the velocity discrepancy observed by OPERA, $\frac{v - c}{c} = 2.9\times 10^{-5}$, would correspond to a delay ("prelay"?) of around 4 years for neutrinos coming from SN1987A. The observed delay was only 3 hours, which is smaller by a factor of roughly ten thousand. So if you assume that (1) the OPERA results are legit and (2) the SN1987A neutrinos travel at the same speed as the OPERA neutrinos, the required corrections to relativity would have to affect stellar models in such a way as to delay escaping photons by almost exactly the right amount of time to cancel out the speed difference at the distance between Earth and the supernova: 4 years, to a precision of $10^{-4}$. That'd be a pretty amazing coincidence. So it seems unlikely.

If you wanted to explain the OPERA results with a modification to relativity (as opposed to them just making a mistake), it seems almost certain that it would have to be some sort of energy-dependent or flavor-dependent effect to be consistent with the supernova. Neither possibility is particularly clean theoretically. (Well, that or the neutrinos we detected from SN1987A actually came from some other source, but again that would require a giant coincidence.)

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"The observed delay was only 3 hours, which is smaller by a factor of roughly ten thousand.". If the superluminal effect is real, and the most realistic model of superluminal particles are still the well-known tachyon kinematics, then the delay factor is a function of the $\gamma$ factor of the tachyon, which is a function of the energy-momenta –  lurscher Dec 2 '11 at 1:38