As we normally count hours numerically adding 1 to the previous hour and as in a normal sequence 12 comes after 11 if it is then 11pm midnight must be 12pm and at the same time 00.00am so 1 minute past midnight is 00.01am the same applies to noon 11am being followed by 12am and at the same time being 00.00pm.
At exactly 12 noon, the Sun is at its highest point in the sky and directly over the meridian. It is therefore neither 'ante' (am) nor 'post' (pm) meridiem. At 12 midnight it also neither am nor pm.
Using numbers from 1 to 12, followed by am or pm, the 12-hour clock system identifies all 24 hours of the day. For example, 5 am is early in the morning, and 5 pm is late in the afternoon; 1 am is one hour after midnight, while 11 pm is one hour before midnight.
Time of the day is divided in two halves (24hour= 12 hours before midday + 12 hours after midday) so the 11 AM is 11th hour before midday as clock strikes 12 again it changes to PM (after midday) so it's 12 PM after 11 AM and 12 AM after 11 PM.
It's all because of the conventions used with the "12-hour clock." 12:00 am is usually taken to mean midnight (and 12:00 pm is noon). At 59 minutes past midnight it is therefore 12:59 am, but a minute later it's 1:00 am.
It is common in transport timetables to use 23:59 Sunday or 00:01 Monday (in this example), or 11:59 p.m. or 12:01 a.m., to further reduce confusion. There are no standards established for the meaning of 12 a.m. and 12 p.m. It is often said that 12 a.m. Monday is midnight on Monday morning and 12 p.m. is mid-day.
The reason a new day starts at 12:00 goes back to ancient Egypt when the day was measured using sundials. The shadow on the face of a sundial tells the time, and the shadow depends on where the sun is in the sky. "When the sun is highest overhead and the shadow goes straight up to the top of the sundial, that's noon.
The ancient Egyptians are seen as the originators of the 24-hour day. The New Kingdom, which lasted from 1550 to 1070 bce, saw the introduction of a time system using 24 stars, 12 of which were used to mark the passage of the night.
What does “a.m.” mean? The term we associate with the morning, a.m., is an abbreviation of the Latin phrase ante merīdiem meaning “before midday.”
12:00AM is the start of the day, so midnight of the day before. How does the 12 hour clock time format work? The 12 hour clock runs as follows: 12:00AM, 1:00AM….
It's no surprise that midnight is the very middle of the night, the word itself stemming from the Old English mid-niht, from mid, "among" or "in the middle of," and night, from niht, which appropriately means both "night" and "darkness."
◊ The abbreviation a.m. stands for the Latin phrase ante meridiem, which means “before noon.”
12pm and 12am do not exist. If they do exist within your applications, remove them. The italicization am stands for ante meridiem, Latin for “before mid-day.” That's the time before the sun is highest in the sky.
The American Heritage Dictionary of the English Language states "By convention, 12 AM denotes midnight and 12 PM denotes noon. Because of the potential for confusion, it is advisable to use 12 noon and 12 midnight."
Noon takes a path through Middle and Old English, where nōn denoted the ninth hour from sunrise. That word derives from the Latin nonus, meaning “ninth,” related to novem, the word for the number nine.
From Middle English gud mornynge (also as goode morne, gode morne), from Old English *gōdne morgen (“good morning”), an ellipsis for an expression such as "I wish you a good morning", equivalent to good + morning.
morning (n.)
"first part of the day" (technically from midnight to noon), late 14c., a contraction of mid-13c. morwenynge, moregeninge, from morn, morewen (see morn) + suffix -ing, on pattern of evening. Originally the time just before sunrise. As an adjective from 1530s; as a greeting by 1895, short for good morning.
There are no exact times for when morning begins (also true of evening and night) because it can vary according to one's lifestyle and the hours of daylight at each time of year. However, morning strictly ends at noon, which is when afternoon starts. Morning can also be defined as starting from midnight to noon.
THE DIVISION of the hour into 60 minutes and of the minute into 60 seconds comes from the Babylonians who used a sexagesimal (counting in 60s) system for mathematics and astronomy. They derived their number system from the Sumerians who were using it as early as 3500 BC.
Who Uses Military Time and When? Military time is used because it avoids the confusion between A.M. (morning hours) and P.M. (evening hours). We are all guilty of accidentally setting our alarm for 6:00 P.M. Instead of 6:00 A.M., causing us to be late to important events.
Since 1967, the second has been defined as exactly "the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom".
Hipparchus, whose work primarily took place between 147 and 127 B.C., proposed dividing the day into 24 equinoctial hours, based on the 12 hours of daylight and 12 hours of darkness observed on equinox days.
Midnight is the zero point in time when we start to build up 24 one-hour periods of time to make up a new day. So midnight is the point 0am. After a period of one hour we reach the point in time called 1am, and after 12 periods of one hour we reach the point called noon.
The Egyptians used a 12-hour sundial to tell time during the daytime and a 12-hour water clock at night. The Romans also used a 12-hour clock. Early mechanical clocks showed all 24 hours, but over time, clockmakers found the 12-hour system simpler and cheaper.