Super Member
How precise can we measure one second? Well...as it turns out, the National Institutes of Standards in Boulder Colorado made a breakthrough in time measurement recently. Based on several atomic clocks, physicists established an optical network of lasers ( propagating both in free-space and within fiber optics ) separated by kilometers with frequency uncertainty around eighteen decimal places. This particularly high-finesse optical network enabled them to compare atomic clocks and establish a method to improve time measurement. Eventually, this technique will help redefine the optical second using a planet-wide network in every metrology institute.