An abandoned rock sample could prove life once existed on Mars. But will it ever reach Earth? - CNN

Scientists have uncovered a previously unknown cleanup system at the back of the eye, revealing a hidden route that allows fluid and waste to escape into the body's lymphatic system. The discovery challenges long-standing assumptions about how the eye functions and could eventually lead to new approaches for treating serious conditions that cause blindness. Glaucoma, age-related macular degeneration, and several other major causes of permanent vision loss are associated with the accumulation of fluid, metabolic waste, and inflammatory material in the back of the eye. Until now, researchers have struggled to explain exactly how this sensitive region removes unwanted substances.