Viewing a single comment thread. View all comments

rocketsocks t1_j603c7x wrote

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

64

MoogProg t1_j60l2cw wrote

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.

23

Eli_eve t1_j612ynt wrote

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.

24

VulpesIncendium t1_j60b4xh wrote

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.

16

Head_Weakness8028 t1_j60dp70 wrote

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

14

Azrael_The_Bold t1_j633ihx wrote

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

3

scratch_post t1_j63ojl2 wrote

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)

3

Head_Weakness8028 t1_j63syr1 wrote

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.

2

H-K_47 t1_j617ukc wrote

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.

8

robit_lover t1_j61gl1v wrote

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.

8

Caspi7 t1_j61a213 wrote

>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.

3

NearABE t1_j60assd wrote

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.

5