According to a recent Penn State study that uses a new way to calculate time-telling precision, the CsF2 cesium-based atomic clock at the UK's National Physical Laboratory is almost twice as accurate as originally thought -- meaning it will only gain or lose one single second over the course of 138 million years. This atomic clock isn't the only competitor for best-in-show, as researchers at the University of Tokyo have also announced a new record, claiming their optical lattice atomic clock observes atoms a million times faster than a traditional atomic clock -- achieving accuracy up to 18 digits in a one sec