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Ask HN: What does 12:00 AM mean?

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Re: Ask HN: What does 12:00 AM mean?

#111

Post by hnbad »

Koshkin wrote: post #85
martin_a wrote: post #62

Earlier quoted context omitted.

Does not make any sense at all. You jump from "sun is overhead in 12 hours" (12 AM) to "sun is overhead in 1 hour" (1 AM) when you follow that logic. The 12 hour-system is broken and should go away.

Would you want the clock face to be changed to show 24 hours instead of 12? (What would be the number at the top then - 0 or 24?)

Easy alternative: start the clock at zero like a rational individual would. 12 only makes sense if you see it as the end and go backwards from there. It's a bit like the confusing mess of how year numbers work where traditionally there is no year zero (because the year one is 1 AD, i.e. the first year "of our Lord", i.e. year numbers are actually ordinal even though everyone treats them as nominal).

Besides, at this point 90% of the time formats people look at in their daily lives are probably digital (since analog faces are only relevant to actual clocks and even most clocks are likely digital simply because so many electronic devices come with digital clocks) and even analog clocks don't always have numbers on them (or use fanciful alternatives like Roman numerals). The people who prefer analog clocks are clearly just sticking with them out of personal preference or aesthetics anyway.

Re: Ask HN: What does 12:00 AM mean?

#112

Post by technobabbler »

majewsky wrote: post #107
technobabbler wrote: post #98

Earlier quoted context omitted.

If you can convince my government and my CEO, I'm game!

I'm propagating the ISO date format with Guerilla tactics. Whenever I come across meeting minutes or documentation pages using a different date format, I silently reformat into ISO date format and then it just catches on. The "normative force of the factual" can be strong.

I like this. The guerilla war for universal understanding!

Re: Ask HN: What does 12:00 AM mean?

#113

Post by majewsky »

Koshkin wrote: post #85
martin_a wrote: post #62

Earlier quoted context omitted.

Does not make any sense at all. You jump from "sun is overhead in 12 hours" (12 AM) to "sun is overhead in 1 hour" (1 AM) when you follow that logic. The 12 hour-system is broken and should go away.

Would you want the clock face to be changed to show 24 hours instead of 12? (What would be the number at the top then - 0 or 24?)

You're making it sound as though a 24-hour format is a wild new idea when it's actually in common use across 100+ countries. Timestamps go from 00:00:00 to 23:59:59 without breaks in continuity. The clock still has 12 hours with the 12 on top, but it is commonly understood that "12" on the clock face can refer to either 0 or 12, just like how "5" can refer to either 5 or 17.

Re: Ask HN: What does 12:00 AM mean?

#114

Post by xiwenc »

Quikinterp wrote: post #5

A lot of my exams will use the time 11:59pm instead of 12:00am to avoid confusion like this

Makes a lot of sense. It’s more a workaround. Also, in your case the date would be:

March 24 at 11:59pm

That would be close to:

March 25 at 12:00am

A bit less confusing but still:

March 25 at 00:00am

Re: Ask HN: What does 12:00 AM mean?

#115

Post by rspoerri »

technobabbler wrote: post #99
sonicggg wrote: post #70

Earlier quoted context omitted.

That was common in my university as well, for the same reason. I think OP's school lacked some common sense with the schedule.

I don't think this is a scheduling thing but a cultural thing. 11:59pm would be 23.59 in other places. The mere use of "11" would suggest morning.

11:59am is 11:59 (in 24h)

11:59pm is 23:59 (in 24h)

afaik everywhere...

but if i understand it correctly:

12:00pm is 12:00 (in 24h)

12:59pm is 12:59 (in 24h)

01:00pm is 13:00 (in 24h)

Re: Ask HN: What does 12:00 AM mean?

#116

Post by njkleiner »

Okay, I'm genuinely confused now, can someone please explain this to me?

First of all, how is nobody taking about the fact that OP was scheduled for an exam that takes place... at midnight.

There are two possible cases here.

Some people are alleging that OP lives in the same place as the exam takes place -- which is not clear to me from the information available -- and use this as an excuse for saying "OP should adopt to local customs".

But that would imply the exam takes place on midnight in local time. Is that actually a thing? Like, is this normal? Why on earth would anyone assume that's the case in an ambiguous situation like this, I can see why you would assume it's at noon without giving it too much thought.

The second case is that OP not in the same place (e.g. the given time at midnight does not match OP's local time), but in this case I blame the institution for allowing people to attend exams remotely while not properly accommodating for time differences.

While 12:00 AM/PM may be technically valid time descriptions, I was under the impression that it was common (in places that use the 12 hour system) to instead write 12:00 noon/midnight specifically to avoid this.

From what I understand, Americans are confused by this too, so why are people so eager to blame Europeans, rather than the system?

Second, I don't understand people saying they use 11:59/12:01 AM/PM as a mnemonic. This makes no sense to me as 00:01 a valid time. How do the above times resolve anything, when all you do is increase/decrease the time, relative to the label, which is what makes it confusing in the first place.

I don't understand how I'm supposed to know which of AM/PM 00:01 refers to, unless I already know what AM/PM means.

Third, people making comparisons to reading an analog clock. When I read an analog clock, I get a time in a 12 hour window. Fair enough. But when I then translate it to 24h, what I do is use my knowledge of whether it is currently day or night to translate it. Which has nothing to do with memorizing which label is which. Analog clocks don't have AM/PM labels so how would this make any more sense?

Re: Ask HN: What does 12:00 AM mean?

#117

Post by GoodbyeMrChips »

goosedragons wrote: post #21

Do Europeans just not have analog clocks or watches anymore?

>Do Europeans just not have analog clocks or watches anymore?

Not in Britain we don't. Analog clocks were abolished by Henry VIII. Since then we kept time using sundials until digital watches were invented in the 1970's and Roger Moore wore one playing James Bond in 'The Spy Who Loved Me'.

Re: Ask HN: What does 12:00 AM mean?

#118

Post by technobabbler »

keiferski wrote: post #77
technobabbler wrote: post #74

Earlier quoted context omitted.

This help domestically, but not across cultures that don't use 12 hour time.

You can always just say 23:59 instead of 12:00 A.M.

Believe it or not, some Americans will be confused by that. Our modern educational systems don't really prepare them for international communications.

It just depends on your audience & context...

Re: Ask HN: What does 12:00 AM mean?

#120

Post by s1artibartfast »

rogual wrote: post #16

Imagine if 12AM meant 12 noon. What would one second past 12 noon be? It'd have to be 12:00:01 PM. Even one millisecond past 12 noon would be PM. So "12AM" could only exist for an infinitesimal length of time, in contrast to 11AM, 10AM etc. which each last for an hour.

12 AM should be replaced by 0 AM, same with 12 PM
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