A very large star explodes, somewhere in the unfathomable space of our galaxy. The star's core collapses. The monstrous pressure crushes its atoms and smashes their electrons into the nuclei. There, the negatively charged protons change to neutrons and neutrinos. Billions of neutrinos particles, that have no electrical charge and little or no mass, escape through the star's outer shell into space. Traveling at nearly the speed of light, they penetrate clouds, reach Earth, and pass harmlessly through the bodies of millions of people and eve ....