Author Carl Zimmer talks to Hari about his new book, "Science Ink."…

A Georgetown neuroscientist's theory on the origins of tinnitus, the phantom ringing that plagues millions of Americans and countless military veterans.

By Jenny Marder

Scientists have coined a new term -- geroscience -- to describe research that aims to slow down aging and delay the onset of age-related diseases like Alzheimer's and Parkinson's. Researchers are studying the underlying genetic causes of aging and effects…