Returning from an ever so brief visit to D.C., where we — Mary, I should say — baby-sat two grandchildren, and I tended largely to the basic needs of a pug who had a heavily bandaged foot (the result of a torn, bleeding toenail), we listened with fascination to NPR’s “TED Radio Hour” as scientists traced (ever so briefly) what’s been going on for the past 13.8 billion years.