Time, the fourth dimension of the world man lives in, is measured by the motion of the earth. The basic unit of time is a day: one revolution of the earth. But recently the battered old earth has ...

A nanosecond (ns) is a unit of time in the metric system, equal to one billionth (10-9) of a second (s). The second is the base unit of time in the International System of Units (SI), making the ...

Scientists are preparing to redefine the fundamental unit of time. It won’t get any longer or shorter, but it will be more precise — and a whole lot more powerful. By Alanna Mitchell Modern ...