Time on the Moon

[PopeTom]

A friend of mine asked on his Live Journal.

What time is it on the Moon?

To which I answered:

You have a few choices.

1) It's whatever time mission control says it is.

2) Greenwich mean time, hard to go wrong with GMT.

3) The complicated way. On day/night cycle on the Moon takes about 28 Earth days to complete. Yet is still takes the Moon 365.25 Earth days to orbit the Sun. So one Moon year is equal to 13.044 Moon days. And one Moon hour is probably something like 1.142 Earth days (27.408 Earth hours). This is of course assuming it is best to break up any planets (or moons) local day into 24 more or less even chunks of time. So I would say that the year on the moon is 2005, just like it is here. There is only one month, January and it is a little over 13 days long so I'd say as of this post it is January 8th. Also as of this post it's probably 11:15 am (or so)

So, as of July 28th at 8:46am on Earth I would say that it is January 8th, 11:15am on the Moon.

Or were you not really expecting anyone to answer this question?

-PT

I figured I'd ask here if the long wordy answer I gave for #3 is correct, or did I make a math error or misassumption some place?


Thanks

-PopeTom

 

[Ladewig]

Doesn't such a question require a place more specific than "the moon." After all, at one part of the moon the sun is rising and at another part it is setting. It doesn't make sense to say that sunrise and sunset occurred at the same time.

Similarly, if a Venusian asked what time it is on earth, more information would be needed.

(Although I do like answer #1.)

 

[Bronze Dog]

I'm suddenly reminded of one bad piece from The Twilight Zone: To Serve Man.

"What time is it?"
Computer: "In space, time requires a point of reference."
"What time is it on Earth?"
Computer: "... It is now twelve o'clock."

 

[PopeTom]

Doesn't such a question require a place more specific than "the moon." After all, at one part of the moon the sun is rising and at another part it is setting. It doesn't make sense to say that sunrise and sunset occurred at the same time.

Similarly, if a Venusian asked what time it is on earth, more information would be needed.

(Although I do like answer #1.)

I'm sure if I had wanted answer #3 to be even longer I could have gone through the bother of splitting the Moon up into different time zones. I guess the first question to ask when doing so would be what spot on the Moon would be the equivalent of GMT? It seems like one could just pick a place, possibly use the longitude of Apollo 11's landing site and work it out from there. Though I think they extra work is a little more then I'd like to do at the moment.

-PopeTom

 

[MRC_Hans]

The faultwith option #3 is that you make a lot of assumptions about how a time system for the Moon might be constructed. Especially that it would be using Earth month and day names. Even if it was designed by earthmen, it is unlikely that they would use such names since that would lead to endless confusion. Also, since months are a function of position relative to the Sun, lunar monght should be synchnized with Earth months. If you wanted to have a measure of the Moon's position in it's Earth orbit, this would be an additional system, between months and days.


Hans

 

[PopeTom]

The names I kept the same just because it seemed a bit easier for a few lines as a comment. Plus I supposed I could have worked it out as one Moon month is a little longer then one Moon day. Though If I needed to name all of those months something different then their corisponding months here on Earth I'd probably name them after women I think are hot.

Which I guess could also make the answer:

Megyn 1st, 2005

-PopeTom

 

[ReFLeX]

"What time is it on Earth?"
Computer: "... It is now twelve o'clock."

Bahahahahaha...

 

[Soapy Sam]

It's about 1.3 seconds from now...

 

[Ririon]

Well, obviously the moon doesn't have months ...

If the earth was moving around the moon as seen from the moon, the year could be divided into "earths", but since the earth stays in the same spot in the sky all the time, that doesn't work, either.

 

[Ririon]

Another thing: Say there was a colony on the Moon, and they decided to use GMT (or whatever timezone Houston or Beijing is in). They would probably want to do some high-tech astronomy-related science there, wouldn't they?

BUT: According to our friend Albert, the high-precision clocks they were using would move at a slightly different rate compared to the ones back home due to the lower gravity... Not significant for everyday living of course, but this gets complicated in principle!

Edited for no apparent reason

 

[epepke]

BUT: According to our friend Albert, the high-precision clocks they were using would move at a slightly different rate compared to the ones back home due to the lower gravity... Not significant for everyday living of course, but this gets complicated in principle!

Also according to Al, the concept of "now" doesn't make too much sense over a distance in space. It's not such of a problem on the Earth, but there's a little more than a second to deal with when you get to the Moon.