It is known, however, that Egyptians once used a calendar that had 12 30-day months, giving them 360 days. This is believed to be the reason why we now divide circles into 360 degrees. 360 divided by 6 is 60, and 60 is also a base number in the Babylonian math system. These abbreviations stand for ante meridiem , before midday, and post meridiem , after midday, and they are a Roman invention. An assistant to the consul was assigned to notice when the sun crossed the meridian, and to announce it in the Forum, since lawyers had to appear in the courts before noon.
Modern man bases time on the second .
A day is defined as 86,400 seconds, and a second is officially defined as 9,192,631,770 oscillations of a Cesium-133 atom in an atomic clock . Inc. All rights reserved.