What is the time zone of the moon?

[wegs]

I’ve looked this up and it seems like the moon and earth are set to universal time. But then I’ve read that the moon has its own unique timezone - “lunar time.”



For simplicity sake, if it’s noon Eastern time in New York, what time is it then, on the moon? (or time difference)

 

[gmilam]

Expanding Earth time zones to include the moon sounds like an exercise in futility to me.

 

[wegs]

I’ve started thinking on it in terms of colonization and time zone structure.

 

[exchemist]

I’ve started thinking on it in terms of colonization and time zone structure.

A lunar day is about a month long (the moon rotates on its axis once every 28 earth days, roughly) whereas the body clocks of human beings are set to coincide with the length of day on earth, more or less. So I presume a colonist will want a 24hr subdivision of time, just as if he or she is still on earth. This will also be convenient for any real-time communication with earth of course, so that you don't get people out of bed by mistake and they don't do the same to you.

Since none of those 24hr subdivisions corresponds to anything recognisable on the moon, it doesn't matter in the least what time you adopt when you arrive on the moon.

 

[billvon]

For simplicity sake, if it’s noon Eastern time in New York, what time is it then, on the moon? (or time difference)

Whatever time you want it to be. It will likely end up as UTC (universal time) since that's what aviation and nautical clocks use.

There's no way to make a human-compatible time work on the moon. A day on the moon is about 28 of our days long, and you can't have people awake for 14 days and then sleep for 14 days. Further, the most likely place for a lunar settlement right now looks like one of the poles, where there is always sunlight (and hence power for solar panels) and there is likely water ice (in the shadows of the craters.) So you wouldn't have darkness anyway.

 

[wegs]

Interesting! So if an astronaut is communicating with earth from the moon, the earth’s timezone is all that would matter? In other words, if he/she were speaking with someone in CA, Pacific time would be the zone considered when referencing the phone call.

 

[C C]

I presume the space station also uses UTC (its time for London/Lisbon or minus any of the positive and negative offsets for its other time zones on Earth). Not the least due to sunrise to sunset every 45 minutes (or whatever) obviously being untenable for days.

If colonists actually live on the surface of the Moon or do a lot of stuff there (rather than underground), then eventually a lunar timekeeping system like below would perhaps be adopted (dual systems used). Lunar days would replace what months are on Earth.

UTC would still apply to coordinated interactions with the Earth in terms of internet and satellite communications, spacecraft travel, etc.

This is supposedly a converter for translating UTC time to the most popular(?) Moon time system: http://lunarclock.org/convert-to-lunar-standard-time.php

The system: http://lunarclock.org/what-is-lunar-standard-time.php

 

[exchemist]

Interesting! So if an astronaut is communicating with earth from the moon, the earth’s timezone is all that would matter? In other words, if he/she were speaking with someone in CA, Pacific time would be the zone considered when referencing the phone call.

Yes. Think about what a time zone is. It is designed so that the sun is approximately at its highest at noon, so that the hours of daylight are roughly when you want them to be for daily life. That is why, when you go west you need a later time zone, since the sun gets to its highest later, the further west you go. (When you go west you are going away from the eastern horizon where the sun rises, so it is going to rise later the further west you go.)

If you are in space, not on the revolving earth, you see the sun all the time. So the whole notion of days is irrelevant. The day is a complete rotation of the earth and if you are not on the earth it doesn't have any significance for you: no sunrise, no sunset, no day and no night.

 

[billvon]

Interesting! So if an astronaut is communicating with earth from the moon, the earth’s timezone is all that would matter? In other words, if he/she were speaking with someone in CA, Pacific time would be the zone considered when referencing the phone call.

That's always true (you have to reference the timezone you are calling.) And people will want to stay on a 24 hour cycle so they will choose waking and sleeping times to be in sync with whoever they are talking to on the Earth - probably the time zone that mission control is in.

It gets a lot more interesting when you are talking about Mars. Mars has a day that is 24 hours and 37 minutes long - close enough to a 24 hour clock that humans will be able to sync to its day/night cycle. Add to that the delay talking between Earth and Mars (6 to 42 minutes round trip) and having conversations at a given time becomes a lot more difficult.

I had a friend who worked on one of the Mars rovers. He had a watch set to Mars time, since the rover only operated during daylight.

 

[Michael 345]

I would presume no real need for the moon to have a independent time zone. Each colony on the moon, Russian, Chinese and American work to their own countries zone

Arrangements can be between the colonies as to best suitable time for each to contact the other

I presume each colony would have someone on the equivalent of a night duty shift

 

[DaveC426913]

I would presume no real need for the moon to have a independent time zone.

There's no reason for the Moon to have a time zone at all (except to coordinate with Earth).

Time zones are based on the day/night cycle, so people are out during the day. They serve no other purpose.

Moon civilization will be mostly underground, so will have artificial light. They are not dependent on the Sun being overhead at noon.

While they may let in natural sunlight, it will not be a criteria for time-keeping on a daily basis.

 

[wegs]

I hadn’t considered the daylight aspect of things ...slight oversight on my part. Lol

Thank you for taking my inquiry seriously and creating an interesting discussion!

 

[Halc]

A lunar day is about a month long (the moon rotates on its axis once every 28 earth days, roughly)

A lunar day is a bit over 29.5 Earth days long (noon to following noon). Earth day similarly is longer than the 23:56 it takes to rotate once on its axis.

Since none of those 24hr subdivisions corresponds to anything recognisable on the moon, it doesn't matter in the least what time you adopt when you arrive on the moon.

It matters if you're communicating with Earth. Probably best to adopt UTC or something. If you're living on the moon long term and actually expecting to schedule your activities around the daylight time, you'd be best off using a local time, which, again like on Earth, is going to have zones depending on your longitude since noon in one place might be post-sunset in another. Who knows what units would divide up a 709 hour day. I'd for one vote to abolish the moronic standard where the little hand goes around twice a day. It should go around once. Make it metric then, with centidays that are about 7 hours long, and millidays which is more than you need to watch an episode of Gilligan's Island. A microday would be 2.5 seconds long. My watch might need 4 hands.

 

[sculptor]

most likely GMT

 

[Benson]

Depends who gets there and sets up a base. If it's the EU bureaucrats, it'll be some kind of metric time system.

 

[DaveC426913]

Depends who gets there and sets up a base.

Good point.

 

[exchemist]

I love the idea of a "metric time zone". Imagine, 100seconds to each minute, 100 minutes to the hour and 10 hours to the day. What could be more rational?

You would have 1000 minutes to each day instead of 3600 and 100,000 seconds instead of 216,000.

 

[DaveC426913]

I love the idea of a "metric time zone". Imagine, 100seconds to each minute, 100 minutes to the hour and 10 hours to the day. What could be more rational?

You would have 1000 minutes to each day instead of 3600 and 100,000 seconds instead of 216,000.

I just finished reading a sci fi book that used exactly that: ksecs, msecs and gsecs.

A 28 hour day would be tough to get used to if you hadn't been born into it.

 

[James R]

Slightly off topic, but as I read this I think of the following: there is no "dark side of the moon".

The moon rotates on its axis about once a month, so any point on the moon is in sunshine for about half of the month, then in darkness for the other half.

Of course, we on Earth only ever see one side of the moon. So the "darkness" is more about our ignorance of the other half than it is about any absence of sunlight.

 

[paddoboy]

Of course, we on Earth only ever see one side of the moon. So the "darkness" is more about our ignorance of the other half than it is about any absence of sunlight.

Actually around 59% is able to be observed from Earth, taking into account the Lunar Libration.