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| Thread ID: 148164 | 2019-08-22 11:09:00 | 12pm is when?? | Zippity (58) | PC World Chat |
| Post ID | Timestamp | Content | User | ||
| 1463237 | 2019-08-22 11:09:00 | www.nzherald.co.nz Just like 12am, 12pm does not exist. It is either noon (12 noon) or midnight (12 midnight). I wish these cheap so called journalists would learn. |
Zippity (58) | ||
| 1463238 | 2019-08-26 02:16:00 | Totally agree, this is why most airlines never have flights departing at this time - the closest is either 11:59 or 12:01 | decibel (11645) | ||
| 1463239 | 2019-08-26 02:20:00 | I agree about 12.00 am usually 00.00 but 12.00 pm as far as I'm concerned both do exist. | paulw (1826) | ||
| 1463240 | 2019-08-26 06:14:00 | I don't know when it is, but I'm guessing we're not there yet. | R2x1 (4628) | ||
| 1463241 | 2019-08-26 06:17:00 | I agree about 12.00 am usually 00.00 but 12.00 pm as far as I'm concerned both do exist. Of course they do. 12am - as you say 00:00 - is midnight and 12pm is midday. Any five year old knows that!:waughh: |
Roscoe (6288) | ||
| 1463242 | 2019-08-26 06:38:00 | There's a clue in the names - AM and PM. One is Ante (before) Meridian, or noon while the other is Post, (after) the noonday sun. The question - is who's Meridian are they talking about? If its a bus driver, they use the Meridian where they are standing. Airline pilots on the other hand have almost nothing to do so they use the Meridian halfway around the world, and to add spice to this trivial in-flight temporal aberration, they ignore the time regular clocks show in favour of time as shown by a sundial in darkest pongolia. ;) Bus drivers Meridians are overhead, pilots have their Meridian underfoot. (Way, way under.) (No conveyor belts were harmed in making this observation) |
R2x1 (4628) | ||
| 1463243 | 2019-08-26 07:22:00 | Bus drivers Meridians are overhead, pilots have their Meridian underfoot. (Way, way under.) (No conveyor belts were harmed in making this observation) If I pm you my address can you send me a 500g bag of whatever you're on. If it's any good, I'll buy another. |
allblack (6574) | ||
| 1463244 | 2019-08-26 17:16:00 | Of course they do. 12am - as you say 00:00 - is midnight and 12pm is midday. Any five year old knows that!:waughh: Time is a bit more complex than this. Each day is of different length, and local noon is when the sun is on the observers meridian, Midnight is when the sun is on the observers anti meridian, and the date changes What is a meridian - Longitude - a great circle passing through the North and South Poles. The Earth's orbit round the sun is an ellipse, with the sun being at one of the foci ( Kepler's laws of Planetary motion), consequently the rate of movement round the earths orbit is not constant, so the actual length of each day varies. A solar day is the period between successive transits of the sun on the observers meridian (Merpass) As the earth is progressing round its orbit, the actual time between successive transits of the sun on the observers meridian will vary as opposed to the case if the earth was stationary. Having day lengths vary is obviously impractical for a time measuring , so the concept of mean or average time is adopted, namely mean time is the average length of a solar day, which is divided into 24 to give the duration of an hour. Greenwich Mean Time, being the mean time at the Greenwich Meridian - ie Longitude Zero. Every location has it's own Mean Time based on its precise longitude, obviously a little impractical, and as the Mean Sun transits 15 degrees an hour, each time zone is 15 Degrees of longitude wide, ie Greenwich from Longitude 7Deg 30' East to 7 degrees 30' West ( Time Zone Zulu) and so on. These time Zones are further modified to ensure that adjacent communities are in the same time Zone, so in Australia we have Eastern Standard Time, Central Standard, and western Standard Time. New Zealand is in time Zone Mike which runs from 172Deg 30 E to 172Deg 30W, (12 Hours ahead of Greenwich) but in fact much of NZ is outside this time Zone - so that is got round by having NZ on permanent 30minutes daylight saving. Longitude 180E or 180W is the International Date Line, but it does not religiously follow that meridian and has kinks in it to ensure that Countries bridging the International Date Line all have the same date. Confused, it's not hard to understand, if you think about it - As a former navigator and navigation instructor it is a while since I have explained it, but perhaps this may help those who are curious or interested in the subject. |
KenESmith (6287) | ||
| 1463245 | 2019-08-26 20:23:00 | Let's show no mercy on R2x1's Bus Driver and get him to take into account: astronomical dawn (sun is 18 degrees below horizon) nautical dawn (sun is 12 degrees below horizon) civil dawn (sun is 6 degrees below horizon) sunrise (sun is 0.833 degrees below horizon to account for refraction) solar noon (sun is at its highest point in the sky for this day) sunset (sun is 0.833 degrees below horizon to account for refraction) civil dusk (sun is 6 degrees below horizon) nautical dusk (sun is 12 degrees below horizon) astronomical dusk (sun is 18 degrees below horizon) That should get the buses running on time! :D |
B.M. (505) | ||
| 1463246 | 2019-08-26 23:08:00 | Actually, to tell the truth, time does not exist in and of itself, it requires an observer to perceive changes in things around it and make the observation that at one time it was like this and now it is changed in some way. | zqwerty (97) | ||
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