Ep. 14 - The Persistent Sundial: From Ancient Egypt to Space

In this episode, we kick off our series on timekeepingdevices. The journey starts with the first known sundials discovered in Egypt. Then we visit ancient Greece and Rome, and the Renaissance, to learn about later developments. We stop in India, where the largest sundial ever built resides. Finally, we discover modern uses for sundials, including why they are being used in space.TIMESTAMPS(00:01) Series introduction: the obsession with time and time-keeping devices.(11:28) Theme of series: the effect of time.(12:02) The rundown.(17:18) Timekeeping before sundials.(21:17) Who invented the sundial, and how does it work?(24:35) EGYPTIAN SUNDIALS INTRO(26:32) Flat “pie-shaped” sundial.(29:50) Early sundial “math” and time.(32:37) Early sundial uses and accuracy.(35:34) Importance of “flat” Valley of the Kings sundial discovery.(39:55) “L”-shaped sundial.(43:30) Early sundials kept seasonal hours.(44:39) How “L”-shaped sundial worked.(46:50) Why seasonal hours?(50:42) Accuracy of ancient sundials compared to modern standards.(51:48) LATER SUNDIALS INTRO(53:40) Ancient Roman and Greek sundials (improvements and art).(56:10) The Earth is round.(58:09) Fun Renaissance sundials and improvements.(62:00) Vikings!(64:09) Ring-sized sundials.(65:22) Giant sundial: the Samrat Yantra.(69:38) MODERN USES OF SUNDIALS INTRO(71:47) Calibrating mechanical clocks.(73:57) Modern usage review.(76:16) Sundials in space! (a touching tale of culture and science)(81:40) SHOW WRAP-UP(82:09) Julia’s big takeaway.(85:12) Greg’s summation.(86:55) Ike!