Author Topic: What time is it on the Moon?  (Read 9684 times)

Offline JohnFornaro

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Re: What time is it on the Moon?
« Reply #20 on: 01/30/2023 10:00 am »
Both on Mars and on Earth you want to have synchronized clocks counting SI seconds from the same epoch.

I think I'm overthinking it.

One day maybe we'll have to solve these problems, but it won't be soon.

Out of curiosity... Will it start being a problem when we colonize Pluto?
Sometimes I just flat out don't get it.

Offline eric z

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Re: What time is it on the Moon?
« Reply #21 on: 01/30/2023 12:31 pm »
 I asked my wife this question and she replied "It's hammer-time!"

Offline litton4

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Re: What time is it on the Moon?
« Reply #22 on: 01/30/2023 01:14 pm »
It's like the problem that the Victorians in the UK solved with "Railway time" vs "local time", only on steroids!

Of course, this eventually became GMT, then UTC
Dave Condliffe

Offline leovinus

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Re: What time is it on the Moon?
« Reply #23 on: 01/30/2023 02:00 pm »
As the thread now converges into a more Computer Science problem, let me add my 2pc. As mentioned above, you ask about clock-synchronization with a fault model. This was well studied in the 1980s even before the Internet with http webpages was active. In fact, one of my friends did a thesis on it.

If you want to learn more then one example paper is at https://groups.csail.mit.edu/tds/papers/Lynch/lncs90-asilomar.pdf
also attached, titled " An Overview of Clock Synchronization" from MIT. The quoted work by Leslie Lamport covers basics. Section 4 "Asynchronous Unreliable Models" seems relevant for solar system distances. There should be more recent overview papers as well.

In any case, this thread started with "on the Moon" and now "on Pluto". The key to keep clocks synchronized is your error model. On Earth, physical distance and number of hubs will probably dominate. And the distance between e.g. Boston and San Francisco does not change. On the moon, the distance would change relative to Earth due to orbits. Then again, the orbits and relative positions of planets and moon are well known.

Gravity was also pointed out as an error source and for that we have gravimeters. I have seen them "car engine" size and ridiculously accurate. They measure the local g acceleration.

So it almost seems this is a graduate-level student exercise to characterize the errors, apply known algorithms, and quantize what level of time difference and synchronization is possible for clocks on Earth vs the Moon or Pluto.

An interesting plot would be for various celestial bodies with an estimate of +/- milli, micro, nano, <whatever level> of difference clocks can be synchronized.

EDIT: NTRS is your friend
https://ntrs.nasa.gov/search?q=%22clock%20synchronization%22
https://ntrs.nasa.gov/citations/19780031873 "VLBI clock synchronization"
https://ntrs.nasa.gov/citations/19750019127 "A relativistic analysis of clock synchronization"
« Last Edit: 01/30/2023 02:04 pm by leovinus »

Offline deadman1204

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Re: What time is it on the Moon?
« Reply #24 on: 01/31/2023 01:55 pm »
I asked my wife this question and she replied "It's hammer-time!"
a geologist at heart!

Offline Tywin

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