Age puzzles go back to antiquity. They challenge us to figure out how ages fit together into a pattern, using a blend of ...

You get older every day. But how old are your cells and organs, really?

When María Branyas Morera turned 116, scientists asked if they could take a peek under the hood. She agreed, cheerfully. Blood, saliva, urine, stool — they wanted it all. What they found was nothing ...