Ask HN: What does 12:00 AM mean? • Hacker News Board

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

#161

Post by basch » Fri, Mar 25, 2022, 2:45 PM UTC

mrsuprawsm wrote: post #128

technobabbler wrote: post #30

You have to learn other cultures' norms if you want to live or work with them. It goes both ways. Europe and America do not only time differently, but phone numbers (1-800-123-1234 in the USA, 06 86 57 90 14 in France), dates (Jan 1 1911 would be 1/1/11 in the USA, 11-1-1 elsewhere), decimals (1,000.00 or 1.000,00), units (inches vs centimeters), reading order, daylight savings time, time zones (some countries don't…

[flagged]

>Only America uses the (nonsensical) MM-DD-YYYY system.

It makes more sense as MMDD-YYYY or (MM-DD)-YYYY. The Month-Day is a single thing, there are 365 of them in a year, in a roughly base 30 counting system. The year can often be left off when colloquially referring to a date (3/14 or 0314 for example.)

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

#162

Post by kcplate » Fri, Mar 25, 2022, 2:45 PM UTC

micromacrofoot wrote: post #145

kcplate wrote: post #123

Earlier quoted context omitted.

Quoted post unavailable.

It's clearly used as an adjective here, which is the pejorative use of the term. It's even packaged in quotes, which alludes to the colloquial form of the word. If you were to use it properly, you'd say "societal progress has been retarded by the U.S." you wouldn't say "the U.S. has done something retarded"

No post body was provided.

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

#163

Post by WithinReason » Fri, Mar 25, 2022, 2:50 PM UTC

xiwenc wrote: post #114

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

Yet another case when 0-based counting makes more sense! ducks

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

#164

Post by beej71 » Fri, Mar 25, 2022, 2:57 PM UTC

For a mathy approach for programmer types, let's switch to decimal hours for a moment. So 12.0 noon is a time, and 12.99 PM is just shy of 1.0 PM.

So is midday AM or PM?

I think we can agree that 30 minutes after noon, or 12.5, is PM.

And we probably also agree that 12.1 would be PM as well.

And 12.0001, that's PM.

We can put as many zeros in there as we want, and it's still PM.

Now put infinity zeroes in there, and you're "at" 12:00 (since that's what the clock now reads) and it's still PM.

A shorthand version of this is if you look at the clock in the middle of the day and it says 12:00, is it exactly 12:00 that very instant? Or is it, infinitely more probably, a little bit past that time? If you know it's a little past 12:00, you know if it's AM or PM.

As for how to fix it, either "noon"/"midnight" or universal 24-hour clocks or memorize that noon is 12 PM. :)

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

#165

Post by pxue » Fri, Mar 25, 2022, 2:59 PM UTC

mrsuprawsm wrote: post #128

technobabbler wrote: post #30

You have to learn other cultures' norms if you want to live or work with them. It goes both ways. Europe and America do not only time differently, but phone numbers (1-800-123-1234 in the USA, 06 86 57 90 14 in France), dates (Jan 1 1911 would be 1/1/11 in the USA, 11-1-1 elsewhere), decimals (1,000.00 or 1.000,00), units (inches vs centimeters), reading order, daylight savings time, time zones (some countries don't…

[flagged]

Wait until you hear what we do in Canada.

We got European/UK roots but since US is next door, in real Canadian fashion we just simple do both. Arbitrarily.

- driving distance and speed is measured in KM and KM/h

- but height, home construction and day to day distance we use imperial. So I'm 5'9" not 175cm. and McDonald's is 100 feet from the intercection, but the next offramp (speedway) is in 3km

- food is all in imperial, so grocery is in pounds, we buy a 12.7oz pint. But liquor stores/bottles are in ML. but if your talk to friends about what to bring to a party, it's back to pint or a "Mickey" or "26er"

- science is all taught in metric.

- But unless you talk cars and motor output, it's back to horsepower (this one is actually pretty common still everywhere in the world).

- And we use centigrade instead of farenheit. So small talk with Americans at work is a constant math excercise.

- Dates are complete utter toss up in the air. My driver license is YYYY/MM/DD, but i know for a fact I've filled out forms that goes MM/DD/YYYY (at the doctors office), and i'm just conditioned to go MM/DD/YYYY when typing dates online because that's how I say it. I don't say 25th of March, I say March 25, 2022.

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

#166

Post by micromacrofoot » Fri, Mar 25, 2022, 3:33 PM UTC

kcplate wrote: post #162

micromacrofoot wrote: post #145

Earlier quoted context omitted.

It's clearly used as an adjective here, which is the pejorative use of the term. It's even packaged in quotes, which alludes to the colloquial form of the word. If you were to use it properly, you'd say "societal progress has been retarded by the U.S." you wouldn't say "the U.S. has done something retarded"

Quoted post unavailable.

No post body was provided.

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

#167

Post by TrianguloY » Fri, Mar 25, 2022, 3:42 PM UTC

12 is 0, that's how analog clocks display time, and that's the only way to make sense of the strange numbering (12->1->2-...>11? What?).

Maybe because Romans didn't have 0? Apparently not, the reason comes from before them, but analog clocks are commonly written with Roman numerals so it's a way to remember this.

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

#168

Post by emerged » Fri, Mar 25, 2022, 3:52 PM UTC

mrsuprawsm wrote: post #128

technobabbler wrote: post #30

You have to learn other cultures' norms if you want to live or work with them. It goes both ways. Europe and America do not only time differently, but phone numbers (1-800-123-1234 in the USA, 06 86 57 90 14 in France), dates (Jan 1 1911 would be 1/1/11 in the USA, 11-1-1 elsewhere), decimals (1,000.00 or 1.000,00), units (inches vs centimeters), reading order, daylight savings time, time zones (some countries don't…

[flagged]

So if an American moved to Japan and was suggested to learn basic Japanese, it would be ludicrous and typically Japan-centric? They have a few customs as well, are those all ludicrous and typically Japan-focused?

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

#169

Post by dudul » Fri, Mar 25, 2022, 3:59 PM UTC

Sorry it happened to you. Yes it would have been better for this institution to send a true calendar event or something that would adapt to each person's local TZ.

That being said, I just googled "12.00 AM" and the very first result is "12.00 AM is midnight". Pretty unambiguous.

If you had never seen this notation before, being an engineer, why didn't you just look it up?

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

#170

Post by signal11 » Fri, Mar 25, 2022, 4:01 PM UTC

mrsuprawsm wrote: post #128

technobabbler wrote: post #30

You have to learn other cultures' norms if you want to live or work with them. It goes both ways. Europe and America do not only time differently, but phone numbers (1-800-123-1234 in the USA, 06 86 57 90 14 in France), dates (Jan 1 1911 would be 1/1/11 in the USA, 11-1-1 elsewhere), decimals (1,000.00 or 1.000,00), units (inches vs centimeters), reading order, daylight savings time, time zones (some countries don't…

[flagged]

> Only America (and partially Canada) use the US customary system (which is different from the Imperial system.

The US armed forces use metric, right?