Author Topic: ESA looking to define a time standard for the Moon  (Read 1557 times)

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Offline HalcyonTopic starter

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ESA looking to define a time standard for the Moon
« on: March 02, 2023, 12:55:01 am »
https://www.esa.int/Applications/Navigation/Telling_time_on_the_Moon

Really interesting reading.

I'd love to see what a "time zone" would look like outside of Earth.
 
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Offline coppercone2

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Re: ESA looking to define a time standard for the Moon
« Reply #1 on: March 02, 2023, 04:15:10 am »
They should put a LF time beacon on the moon too. I wonder if they can send the Loran hardware up there, must be some left in reserve.


If you start small scale lunar manufacturing, a LF beacon would be perfect to allow for cheap precise easy to make lunar electronics.
« Last Edit: March 02, 2023, 04:26:48 am by coppercone2 »
 

Online SiliconWizard

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Re: ESA looking to define a time standard for the Moon
« Reply #2 on: March 02, 2023, 05:48:42 am »
Not sure I really see a point not being at Earth time, although I admit I don't know how "days" feel up there. That must be a harsh enough change that time itself is probably only a minor consideration.

Anyway, I guess
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Offline ConKbot

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Re: ESA looking to define a time standard for the Moon
« Reply #3 on: March 02, 2023, 12:34:42 pm »
Well I'm sure the people in the meetings needed something to do.
 

Online nctnico

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Re: ESA looking to define a time standard for the Moon
« Reply #4 on: March 02, 2023, 01:34:23 pm »
https://www.esa.int/Applications/Navigation/Telling_time_on_the_Moon

Really interesting reading.

I'd love to see what a "time zone" would look like outside of Earth.
Add to that the fact that the moon is circuling around the earth so there will also be Lorenz contraction to account for. With missions to Mars in mind (different speed compared to earth so a different time -again-), it is time to think about a universal solar time which is equal within the entire solar system. A second isn't a fixed value...
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Offline xrunner

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Re: ESA looking to define a time standard for the Moon
« Reply #5 on: March 02, 2023, 01:55:49 pm »
MST - Moon Standard Time.  ;D
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Offline Stray Electron

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Re: ESA looking to define a time standard for the Moon
« Reply #6 on: March 02, 2023, 02:28:45 pm »
MST - Moon Standard Time.  ;D


   MST is already taken; Mountain Standard Time.

  What's wrong with Coordinated Universal Time? Or this group just looking for an excuse to name something else for Martin Luther King, George Floyd or one of the other PC counter culture icons?
 

Online tggzzz

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Re: ESA looking to define a time standard for the Moon
« Reply #7 on: March 02, 2023, 03:20:42 pm »
I see three main issues:
  • defining a time system for on and orbiting the moon
  • accounting for the astronomical and relativistic differences
  • defining the time visible on earth

The first seems tractable, and relatively boring.

The second is well known from physical principles, but the details are probably difficult to resolve.

The third I simply don't understand. Imagine sending pings between the earth and moon. If someone sends ping1 the earth at time t, the signal will take 1s to reach the moon, and an instantaneous ping2 response would arrive back on earth at time t+2. Earth then sends ping3.

At what time do all parties agree  the ping1 received on the moon?
At what time do all parties agree the ping2 received on earth?
At what time do all parties agree  the ping3 received on the moon?

There are already analogies on earth. For example, the high frequency trading mob have to deal with the latency between Chicago, New York and London - and use it to their benefit during arbitrage trades. On a smaller scale, the path delay across a modern IC is much longer than the gate delay, and can be several clock cycles.

Leslie Lamport's seminal papers had something to say about this back in 1978 :) http://research.microsoft.com/users/lamport/pubs/time-clocks.pdf
He won a Turing Award for that! https://amturing.acm.org/award_winners/lamport_1205376.cfm
« Last Edit: March 02, 2023, 03:29:08 pm by tggzzz »
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Offline MarkS

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Re: ESA looking to define a time standard for the Moon
« Reply #8 on: March 02, 2023, 04:00:12 pm »
   MST is already taken; Mountain Standard Time.

LST? Lunar Standard Time?
 

Online nctnico

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Re: ESA looking to define a time standard for the Moon
« Reply #9 on: March 02, 2023, 05:11:16 pm »
UST Universal Space Time
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Offline Stray Electron

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Re: ESA looking to define a time standard for the Moon
« Reply #10 on: March 02, 2023, 05:47:26 pm »
I see three main issues:
  • defining a time system for on and orbiting the moon
  • accounting for the astronomical and relativistic differences
  • defining the time visible on earth

The first seems tractable, and relatively boring.

The second is well known from physical principles, but the details are probably difficult to resolve.

The third I simply don't understand. Imagine sending pings between the earth and moon. If someone sends ping1 the earth at time t, the signal will take 1s to reach the moon, and an instantaneous ping2 response would arrive back on earth at time t+2. Earth then sends ping3.

At what time do all parties agree  the ping1 received on the moon?
At what time do all parties agree the ping2 received on earth?
At what time do all parties agree  the ping3 received on the moon?


   I wonder if they'll want to divide Moon Time into zones like they did with time zones on the earth?   If local Moon Time roughly follows the lunar sun rise and sun set as it does on earth, then Moon Time Zones will be completely out of sync with anything that we're familiar with.

   It sounds like someone is about to propose a very complex answer to a problem that really doesn't exist yet.
 

Online tggzzz

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Re: ESA looking to define a time standard for the Moon
« Reply #11 on: March 02, 2023, 08:03:59 pm »

  • defining the time visible on earth


The third I simply don't understand. Imagine sending pings between the earth and moon. If someone sends ping1 the earth at time t, the signal will take 1s to reach the moon, and an instantaneous ping2 response would arrive back on earth at time t+2. Earth then sends ping3.

At what time do all parties agree  the ping1 received on the moon?
At what time do all parties agree the ping2 received on earth?
At what time do all parties agree  the ping3 received on the moon?

There's one simple answer: take the average relativistic dilation factor between Earth's surface and the Moon's surface. Then, change the number of seconds in an hour by that factor. A lunar hour might have 60.0000005 Earth seconds in it.

That answer may turn out to be relevant to the part of my post that you didn't quote. It isn't relevant to the part you did quote.
There are lies, damned lies, statistics - and ADC/DAC specs.
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Online tggzzz

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Re: ESA looking to define a time standard for the Moon
« Reply #12 on: March 03, 2023, 09:55:56 pm »
The difference between the terrestrial HFT mob and the Moon is that there's no significant relative time dilation between points on Earth's surface. Everyone is co-moving around the core at the same distance in the same gravity well.

This source claims the effect is only 0.66 parts per billion, so about 2 seconds every 100 years. Significant for GPS/RTK applications but not much else.

That is a difference. It is not the only difference, nor is it the most interesting and difficult to resolve difference.
There are lies, damned lies, statistics - and ADC/DAC specs.
Glider pilot's aphorism: "there is no substitute for span". Retort: "There is a substitute: skill+imagination. But you can buy span".
Having fun doing more, with less
 

Online nctnico

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Re: ESA looking to define a time standard for the Moon
« Reply #13 on: March 04, 2023, 10:36:12 pm »
The difference between the terrestrial HFT mob and the Moon is that there's no significant relative time dilation between points on Earth's surface. Everyone is co-moving around the core at the same distance in the same gravity well.
Not quite. Due to the rotational speed of the earth, network packets (or better put: the electrical or optical signals that represent the data) will move at different speeds depending on which direction they are travelling. https://en.wikipedia.org/wiki/Sagnac_effect Precise time distribution systems have to compensate for this effect.
« Last Edit: March 04, 2023, 10:38:01 pm by nctnico »
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 
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Online Alex Eisenhut

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Re: ESA looking to define a time standard for the Moon
« Reply #14 on: March 04, 2023, 10:53:59 pm »
Will there also be a Moonlight Savings Time?
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