The only thing more vague and undefined than Space Law is Time Law.
However, in this universe, we obey the Laws of Thermodynamics. Unless you have this daemon who stops all of the slow moving particles and lets the fast ones pass…
Can you find a law to the contrary? Every law in my state based on age that I’m aware of does not take into account what time of day one is born. For instance, to apply for a student learner’s permit, you must be at least 16 years old. A lot of kids do this on their 16th birthday, even if they were born at 11:59 PM. You have to know this based on having similar life experiences to mine.
The one that is commonly used is that you are of a new age at midnight on your birthday. I don’t know of a place where it’s common to take into account what hour or minute one was born at.
Why is that relevant? It’s not uncommon for young people to go to bars and order a drink at midnight on the day they turn 21 (allowed in most states). It’s never based on what time of day one was born at.
Back in the early 80’s in Missouri a friend was going to turn 21 on a Sunday. The bar advertised “open until 02:00 on Saturdays” so we went in just after midnight. The doorman turned her away with the explanation that since the bar wasn’t allowed to open on Sunday 02:00 was still counted as Saturday.
My point is that there might not be any law that clearly defines what it means to be a certain age, and then you have to use the common English definition.
And there are reasonably two different definitions for age. One that is discrete, based on time boundaries like days and time zones, and one that is continuous.
What you’re arguing is that everyone generally uses the discrete one, because it’s easy and we have IDs that specify day, but not hour, minute, or location. Which I don’t disagree with. That is the system that basically everyone uses.
But is that the only definition a court would accept? I’m not 100% sure that it is.
How about DST? I was born at something like 11:45pm in a month when DST was in common use, but not officially recognized. In common use, it 12:45am on the 10th, but it was recorded as 11:45pm on the 9th. In subsequent years, DST has become officially recognized, but my birthday is still the 9th.
Kind of a variation on the OP. Something I pondered when I started visiting the south pacific.
So when you fly west across the date line, you lose a day. Like you fly 11 hours, but it is actually a whole day “past” when you left. This all works out because when you fly home (east), you can sometimes land “before” your departure day/time. So you gain back that lost day.
But what if, after flying west across the dateline, you continued west ? When you finally get back to your origin point, you will have “skipped over” a day. You would never recover that day. So it is as though you “aged less” by the lost day. By the calendar, you are one day older, but you actually haven’t lived that many elapsed days.
So if, say, you were rich enough and didn’t have the patience to wait, say 5 days to turn 21, but wanted to attend this big party, you could start doing laps, westward, around the world to “skip” over days.
As you fly west, each time zone you cross makes it an hour “earlier”. Then there’s a big discontinuity at the international date line, that jumps to 24 hours “later”. If you go less than one revolution, then you can either relive some calendar hours or skip them, depending on starting and ending points. But the net change if you keep going averages to zero.
Think about it this way: If you fly all the way around the world and land back where you took off from, the time you land is however long it took you to fly around after the time you took off. No day-skipping.
Suppose you had an infinitely fast jet. You are in the Cook Islands where the current time is 9:00 AM on Tuesday. You fly your jet instantaneously to New Zealand where it is now 8:00 AM on Wednesday. Woo hoo, you just gained a day. You want to keep this going on so you continue flying west back to the Cook Islands where it is 9:00 AM on Tuesday again (because you passed through 23 time zones along the way) and the whole process restarts.
Related question: what would be the legal status of a baby born on, say, March 8 in Samoa, who then immediately travels to American Samoa, where it was still March 7? Would they not exist?
(I suppose it’s a moot point, because most births aren’t registered until several days after the event, anyway - but if, say, some medical procedure had to be recorded on that day, it could create some interesting problems!)
Another related question. Say you live in New Mexico (mountain time) just across the border from Texas (central time). You drive into Texas to meet your friends at a bar to celebrate your 21st birthday at midnight. At 12:00 everyone buys you shots at you quickly get hammered. At 12:20 you leave the bar to drive home. You arrive back in your New Mexico neighborhood at 11:40, get pulled over, and after a breathalizer test are cited with a DUI. Can they also cite you for underage drinking?
The good Dr. Asimov speculated many years ago about the effect of time and law. If you have 3-4 minutes, please consider this little tale: A Loint of Paw - Asimov's Mysteries
I’m sure it depends on the laws in that jurisdiction, but it doesn’t appear that they drank in a jurisdiction where they were underage. Any drinking was legal and took place in Texas. DUI is a crime regardless of your age, although there may be increased penalties for DUI depending on the driver’s age.
I think other posters have figured it out, but I’ll still put my two cents in. I am pretty sure if you’re located in a time zone in which you had not yet turned 21, even though having legally turned 21 in your starting location, you would be committing a crime.
However, I’m pretty sure you’d have to be intensely unlucky to be caught and tried.
So, in conclusion, I hope when you turned 21, you drove “backwards in time” and illegally drank some alcohol. That would be a pleasing end to this thought bubble. If you didn’t, shame on you.