A sneeze rips when something irritates or tickles the inside of your nose. It can be any sort of irritant, from a feather or germ to pepper or pollen. Most people know that. But did you know that several other not-so-obvious things can also cause this explosive, involuntary reaction? Bright light, like that from the sun, triggers about 1/3 of people; it’s called photic sneeze reflex. For some, stuffing themselves is also a reason; it’s called snatiation (a mix of sneeze and satiation). New science says an achoo is your nose rebooting itself like a computer does. Sometimes your nose is just overwhelmed and needs to restart. But a nightmare doesn’t cut it. That’s because the nerves in your nose are asleep just like you.