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Europe pushing for lunar time zone

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Re: Europe pushing for lunar time zone

#41

Post by ssivark »

BerislavLopac wrote: post #30
wolverine876 wrote: post #24

Earlier quoted context omitted.

> What we should really do is just get rid of all this crap and go with metric time that starts at an arbitrary moment and isn’t dependent on location. What do you do about relativistic effects which cause time to move at different rates in different places, including on the Moon. From TFA: > Clocks run faster on the moon than on Earth, gaining about 56 microseconds each day, the space agency said. Further complicati…

How is that even possible? Does cesium have a different frequency there?

Yes — relativistic effects are so fundamental that they affect every system/process (including atomic clocks ) and therefore any measurement scheme. That’s why we talk about “time slowing down”. The movie Interstellar has one popular depiction of this.

Re: Europe pushing for lunar time zone

#43

Post by Beldin »

tanbog5 wrote: post #27

Are relativity effects significant on the moon? I thought a rationale for this was the need to account for relativistic effects making clocks run at slightly different speeds on the moon than on the surface of the earth. Is the "timezone" more of conversation protocol for earth time to moon time? Current missions use a synchronised mission clock and don't last long enough for this to be a big issue right?

> Are relativity effects significant on the moon?

Yes, as the article states, clocks run faster on the Moon. About 56 microseconds per day.

Be that as it may, as far as I know, Newtonian gravity was sufficient for the moon landings. So I'm guessing this is more of a coordination issue between countries than a necessity for trajectories or such.

Re: Europe pushing for lunar time zone

#44

Post by doctor_eval »

alex_young wrote: post #31

A zone of what though? Time zones, are zones of our planet where we observe time in some coordinated fashion. If we're adding the moon, what part of our globe should it be considered a part of? This all seems pretty silly.

It’s not about creating an earth based zone for the moon. It’s about creating a system of recording time that works on the moon. Time doesn’t work the same on the moon as on earth, so why should they be linked?

Earth clocks are basically about the position of a point on earth, relative to the sun. The moon’s relationship with the sun is quite entirely different. So where is the equivalent of Greenwich on the moon? Does that even make sense? What is the equivalent of a day? Will there be weeks?

Earth clocks and moon clocks don’t run at the same time, due to relativity. And I guess the relationship between earth and moon time is far from linear depending on their relative positions and the sun’s.

So there is lots of interesting stuff to be worked out, and I don’t think it’s silly at all.

Re: Europe pushing for lunar time zone

#46

Post by Scarblac »

BerislavLopac wrote: post #30
wolverine876 wrote: post #24

Earlier quoted context omitted.

> What we should really do is just get rid of all this crap and go with metric time that starts at an arbitrary moment and isn’t dependent on location. What do you do about relativistic effects which cause time to move at different rates in different places, including on the Moon. From TFA: > Clocks run faster on the moon than on Earth, gaining about 56 microseconds each day, the space agency said. Further complicati…

How is that even possible? Does cesium have a different frequency there?

Relativity, different gravity well. Cesium is the same, actual time is different.

Re: Europe pushing for lunar time zone

#47

Post by slow_typist »

BerislavLopac wrote: post #30
wolverine876 wrote: post #24

Earlier quoted context omitted.

> What we should really do is just get rid of all this crap and go with metric time that starts at an arbitrary moment and isn’t dependent on location. What do you do about relativistic effects which cause time to move at different rates in different places, including on the Moon. From TFA: > Clocks run faster on the moon than on Earth, gaining about 56 microseconds each day, the space agency said. Further complicati…

How is that even possible? Does cesium have a different frequency there?

It does. Not for the observer on the moon, but on the earth.

Hafele-Keating experiment:

https://en.m.wikipedia.org/wiki/Hafele–Keating_experiment

Re: Europe pushing for lunar time zone

#48

Post by rascul »

RheingoldRiver wrote: post #36
rascul wrote: post #8

I would be happy if we got rid of timezones, got rid of daylight savings time, and got rid of 12 hour clocks.

No, you wouldn't: https://qntm.org/abolish

Yes, I would.

If I need to call someone in their morning, I need to determine the same offset.

I have plenty experience with both ends using UTC regardless of where in the world they are. It's much easier. Either 0425 works for both or we need to adjust one way or the other. I still need to know that your schedule is four hours ahead of mine, but we don't need to do math to figure out what time 0425 is. The cognitive overhead is diminished.

Re: Europe pushing for lunar time zone

#49

Post by paxys »

BerislavLopac wrote: post #30
wolverine876 wrote: post #24

Earlier quoted context omitted.

> What we should really do is just get rid of all this crap and go with metric time that starts at an arbitrary moment and isn’t dependent on location. What do you do about relativistic effects which cause time to move at different rates in different places, including on the Moon. From TFA: > Clocks run faster on the moon than on Earth, gaining about 56 microseconds each day, the space agency said. Further complicati…

How is that even possible? Does cesium have a different frequency there?

Because spacetime. Clocks run at different speeds depending on the gravitational field in which they operate. This is true for any two clocks, not just between earth and the moon. Satellites have to constantly correct their clocks for the same reason.

Re: Europe pushing for lunar time zone

#50

Post by ragebol »

BerislavLopac wrote: post #30
wolverine876 wrote: post #24

Earlier quoted context omitted.

> What we should really do is just get rid of all this crap and go with metric time that starts at an arbitrary moment and isn’t dependent on location. What do you do about relativistic effects which cause time to move at different rates in different places, including on the Moon. From TFA: > Clocks run faster on the moon than on Earth, gaining about 56 microseconds each day, the space agency said. Further complicati…

How is that even possible? Does cesium have a different frequency there?

Nope, those are relativistic effects. This dude called Einstein had a few things to say about it: https://en.wikipedia.org/wiki/Theory_of_relativity

One of the effects in time dilation, where moving clocks are measured to tick more slowly than an observer's "stationary" clock.

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