Time expert Philippe Richard on why scientists are changing how we keep time

Scientists have voted to change how the world keeps time, but most people won't even notice. NPR's Scott Simon talks to Philippe Richard, director of Switzerland's Federal Institute of Metrology. NPR Science LISTEN & FOLLOW NPR App Apple Podcasts Spotify Amazon Music iHeart Radio RSS link Science Time expert Philippe Richard on why scientists are changing how we keep time October 24, 20267:42 AM ET Heard on Weekend Edition Saturday Scott Simon Time expert Philippe Richard on why scientists are changing how we keep time Listen · Transcript Toggle more options Download Embed Embed <iframe src="https://www. npr. org/player/embed/nx-s1-6011081/nx-s1-9977325" width="100%" height="290" frameborder="0" scrolling="no" title="NPR embedded audio player"> Transcript Scientists have voted to change how the world keeps time, but most people won't even notice. NPR's Scott Simon talks to Philippe Richard, director of Switzerland's Federal Institute of Metrology. Transcript SCOTT SIMON, HOST: One day, one full rotation of the Earth takes exactly 24 hours, right? The Earth's spin has slowed down ever so slightly so that one rotation is 24 hours and some number of microseconds. Since 1972, we have been adding leap seconds every few years to make up that difference, but that is about to change. He's director of the Swiss Federal Institute of Metrology. Thank you for being here. And metrology, that's the study of measurement? Thank you for inviting me. SIMON: What does it matter if we're off a few microseconds? RICHARD: It's not so big, but maybe - you made a great introduction. But if you agree, I want to tell you a short story of two watches to introduce the concept. RICHARD: Imagine you have two watches, a nice, old Swiss mechanical watch and a modern, precise quartz watch. If you compare them, you will soon realize that the time difference will probably increase with time, and if you want your quartz watch to follow your old Swiss watch, you will have to correct your quartz watch . So let's now imagine your old Swiss mechanical watch is the Earth, which rotates on its axis in 24 hours. So the necessary correction to follow the Earth's rotation is what we call a leap second. SIMON: So there's been a vote recently a part to no longer use leap seconds? There was the General Conference on Weights and Measure last week in Versailles, close to Paris, and member states decided to abandon the concept of leap second.