In the early morning hours of Feb. 24, 1987, a neutrino sensor located deep below a mountain in the north of Italy started to pick up a rapid explosion of neutrinos. Three hours after this, neutrino sensors at two other sites also picked up parallel bursts.
About five hours after the second event, astronomers who were examining a large Magellan cloud which orbits the galaxy, happened to notice the startling enhancement of a blue supergiant star known as Sanduleak-69 202, as it became a supernova. Since that time, its name has changed to SN 1987a, and it would become one of the most broadly studied supernovas in space history. Yet there continues to be a large mystery linked with SN 1987a that astrophysicists have basically ignored : the two neutrino bursts separated by the span of several hours.
Both neutrinos and photons travel at the speed of light and therefore should arrive somewhere at the same time, all things being equal. The mystery is what caused such a huge delay between the first eruption of neutrinos and the onset of the optical photons.
Read more at : http://www.sott.net/article/280952-Evidence-of-a-correction-needed-to-change-speed-of-light-possibly-found