You—and every square inch of Earth’s surface—are being continuously bombarded by neutrinos from space. Billions of neutrinos slice through your body every second.

Fortunately, neutrinos are so unlikely to interact with any matter—including the atoms and molecules in the human body—that the billions upon billions of neutrinos that hit you every second have no discernible effect at all. In fact, the odds that any neutrino striking Earth will interact with any atom in our planet at all is about one in a billion. Even when it does happen, the result is merely a tiny flash of harmless light.