There are hundreds of atomic clocks in orbit right now, perched on satellites all over Earth. We depend on them for GPS location, Internet timing, stock trading … and space navigation?Today on the show, hosts Emily Kwong and Regina G. Barber learn how to build a better clock. In order to do that, they ask: How do atomic clocks really work, anyway? What makes a clock precise? And how could that process be improved for even greater accuracy?For more about Holly’s Optical Atomic Strontium Ion Clock, check out the OASIC project on NASA’s website.For more about the Longitude Problem, check out Dava Sobel’s book, Longitude. Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave.Have questions or story ideas? Let us know by emailing [email protected]!