WHEN I FIRST started running long distances, I had one goal: go as fast as I could for as long as I could. I ran the same 5k route a few times a week, always aiming to go faster. Every time out needed ...

It's time now for our science news roundup from Short Wave, NPR's science podcast. I'm joined by two of the show's reporters, Regina Barber and Rachel Carlson. Hey, y'all. REGINA BARBER, BYLINE: Hi.