[removed]

[removed]

[removed]

Spoilers: it's going to be UT/GMT for a long time until someone figures out something better.

Really cool, interesting things to consider. Wait until we get lunar trains and they will need to work out which lunar time zone to leave at

[removed]

Earth will be overhead for all of the near side. Using the apparent location of the GMT line would add 49 minutes to every day. That allows time for sleeping in and generally relaxing.

The direct lazer communication lines would rise at the same time everyday. Geostationary satellites would eclipse at the same time everyday too.

IMO, they should just permanently stick with GMT on the Moon. Maybe it could have its own designation (Moon standard time?), but whatever that is, it should simply match the current GMT. Anything else would get too complicated to reconcile with Earth schedules.

Now, a permanent Mars colony is where time zones would really get tricky. The Martian day/night cycle is close enough to Earth's that it would be awkward to force an Earth based 24 hr schedule there.

I imagine we will need to have a “universal time” for trans-system travel and communication. Then the local rotational time for inhabited location.

You only need time zones if by definition you have access to daylight, and you depend on daylight. People who don't need that, like submarine crews, just run on an arbitrary time.

There's no reason why the entire Moon can't be on the same time zone, as the lunar day isn't 24 hours anyway, it's more like 27 days, and pretty much everyone will be underground.

So everyone will be on Coordinated Lunar Time, which will be abbreviated to LTC in a compromise with the French speaking world.

Fuck. Just fuck. Moon time zones. Fuuuuuuuuuuuuuck. Coding for earth‘s timezones is shit and now this is added.

Well, it would be sync'd to UT/GMT but there will be differences in actual time between the two frames of reference. Set the Moon clock to UT/GMT running the same method of timekeeping as Geneva, they will drift apart from each other due to the relativistic effects of gravity. How that gets negotiated will be interesting. The Moon and Mars have their own time, no matter what 'zone' we apply to keep track of things. Crazy stuff.

Can you imagine when people are living up there and we have to work out business times over emails and such?

[removed]

Since these settlements will be way underground, anyhow, theres no point in synchronizing from 'solar noon to solar noon'...Just sync to GMT. Makes any kind of concerted effort with Earth way easier, too.

I read an estimate of about 22 milliseconds per year time difference between Earth and Moon due to relativistic effects. Which is about 1 second every 45 years or so. Probably just an easy leap second every half century.

More importantly, will this have any implications for monthly earth-based credit card due dates

1 day on Mars is equal to 1 day and 37 minutes on Earth. In the Mars SciFi trilogy, they just used a standard 24 hour clock and the extra 37 minutes was just used as a spare break time.

Just use Zulu. It's not like the rotation of the moon is rapid enough to necessitate a "day"; not unless you wanna have six sleeps before noon.

>they should just permanently stick with GMT on the Moon.

The moon takes 27 days to rotate around its axis. So a 648 hour day/night cycle would make that much sense.

Doesn't time pass slightly different on the moon?

The clocks will need periodic resyncing to Earth time.

The problem is that if you wake up at the same time every morning, every day you're 37 minutes more out of sync with sunrise and sunset, which would be unacceptable when spacewalks are common.

It does, but the same is true for satellites, and the answer for both is to build a clock that if run on earth would be wrong, but in it's designed environment is perfectly synced with clocks on earth.

[removed]

Just wait til they try to figure out what time it is on the sun.

But Zoom calls, cameras on, would be worth the hassle!

[removed]

[removed]

GMT hasn’t existed since 1972

Just use the same mathematical equations used to determine "time" on Earth, and apply it to the moon

[removed]

[removed]

[removed]

[removed]

[removed]

[removed]

“Galactic Mean Time,” or, GMT? And just have it mirror actual GMT XD

It’s totally arbitrary, so just pick whatever and go with it. How about GMT+24?

Universal time doesn't make sense in the context of General Relativity. The only thing two observers in different reference frames can agree on is what is known as the 'spacetime interval.' Caused by the Lorentz contraction. This interval is both a distance and a time measurement, which you're likely already familiar with. Afterall, when you want to meet with someone, you have to give a minimum of two abstract things, a location, and time. spacetime interval^2 = ({change of time}*c)^(2) - {change of x}^(2) - {change of y}^(2) - {change of z}^(2)

I was legitimately fishing for this clarification. I was aware of the problem with general relativity, but wasn’t specifically certain on how to rectify it.

No need for different time zones on the moon as has been mentioned. I’d say UTC would be fine. With Mars you have to account for the extra 36 minutes. Like in DS9 Bajor had a 26 hour day. So, they are going to need new clocks. If we ever establish Martian colonies I imagine clocks will be a very minor concern.

Probably would match whatever time zone Mission Control would be. Everyone working the same hours basically.