AP Photo

February 23rd 1987 is a day indelibly imprinted on the minds of everyone interested in astrophysics. At 7:36 GMT that day, now 25 years ago, the big one hit us. There was no escape. For 13 seconds a tsunami of neutrinos, emanating from a giant star eleven billion times more distant than the sun, flooded earth. This wave of neutrinos paled the steady stream of neutrinos reaching us from the sun by a factor of more than ten thousand.

Yet no one noticed.