#47 Humans Can’t Cry In Space
While in space, the zero-gravity atmosphere doesn’t allow the tears to roll down your cheeks as they normally would. No matter how hard you try to cry, the saline water will stay in your eyes and curl up into a ball and will stay there permanently until you wipe it off.
Amused by this impossible theory, an astronaut even tried to do it practically and tasted the sour side of this experiment. According to him, it was the most annoying experience of his life.