3 months ago
Last edited at 12:34PM on 12/2/2013
Neither 12A.M. or 12P.M. are technically correct, because A.M.(Ante Meridiem) refers to the time BEFORE Midday / noon and P.M.(Post Meridiem) refers to the time AFTER Midday/noon. The Romans would not have had a need to assign A.M. or P.M. at the Midday or Midnight interval, because they did not digitize time and Midday/noon or Midnight was the appropriate term for the exact time of the meridiem. However, given the constraints of the modern world and the desire to express the day in either A.M. or P.M., the most appropriate answer is that 12 A.M. equals Midday/Noon and 12 P.M. equals Midnight. The new day begins after midnight of the previous day.Therefore, the standard convention says that 12 o’clock is Midnight, so the first second after midnight is 12:00:01 and since it is before Midday/noon of the that day, we label this A.M. which makes the first second of the day is 12:00:01A.M. The last second of the first 12 hours falls at 12:00:00A.M. which is Midday/noon. The first second of the following 12 hours starts at 12:00:01P.M. which is after Midday/noon and the last second of the last 12 hours of the day is 12:00:00P.M. which coincidently is midnight the last second of the day.