Resumen de Every second counts
The concept of dividing the day into smaller units goes back to the Bronze Age at least but the invention of the modern second is usually attributed to Persian polymath Al-Biruni around the end of the first millennium AD. He took the hour--a unit of 1/24 of the day already used by the Greeks and Sumerians among others--and subdivided it twice by 60. Latin scholars later christened the second of these units "secunda," corresponding to 1186,400 of a day. Here, the historical link between astronomy and time is discussed.
