“I’m looking at a picture of two mice. The one on the right looks healthy. The one on the left has graying fur, a hunched back, and an eye that’s been whitened by cataracts.” What’s the difference? Well, scientists at the Mayo clinic used a process to remove senescent (or retired) cells from one of them. And that process leads to mice who age better and live longer. As one researcher not connected to the study explains: “The usual caveats apply — it’s got to be reproduced by other people — but if it’s correct, without wanting to be too hyperbolic, it’s one of the more important aging discoveries ever.”

+ And we want you living a long, healthy life. Because it turns out you probably won’t reach your happiest level until you’re 65.