The Geochron World Time Indicator is a clock that doubles as a live map of where the sun is shining on the Earth. Back in its day, it was a cult piece that some have dubbed the “Rolex on the ...

Now a Japanese company has commercialized one approach—an optical-lattice clock it claims is the most accurate on the market.

Big Ben: Saving the World's Most Famous Clock is available to stream on pbs.org and the free PBS App, available on iPhone, Apple TV, Android TV, Android smartphones, Amazon Fire TV, Amazon Fire ...