In 1989, Professor Tsvi Piran of the Hebrew University of Jerusalem predicted (in the journal Nature) that the merger of two Neutron stars would produce a burst of gamma rays. He was either ignored or met with skepticism. Now 28 years later, his prediction was proved correct.

http://new.huji.ac.il/en/article/35910

http://www.nature.com/nature/journal/v340/n6229/abs/340126a0.html?foxtrotcallback=true (1989 article)