The title is slightly misleading -- strictly speaking, they aren't just giving the moon its own time "zone", they're giving it a reference time.
what's the different exactly @jxf?
Europe pushing for lunar time zone
261–270 of 406 posts
Re: Europe pushing for lunar time zone
#262> There are also technical issues to consider. Clocks run faster on the moon than on Earth, gaining about 56 microseconds each day, the space agency said. Further complicating matters, ticking occurs differently on the lunar surface than in lunar orbit.
As a programmer, I can feel a migraine coming on just thinking about the bugs this is going to cause.
Re: Europe pushing for lunar time zone
#263Earlier 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?
The really weird part to get your head around here is that in case of relativistic differences, it's actually time that's changing. So cesium still has the same frequency, the same number of events per second, but their second is not the same as ours.
When people talk about clocks running faster or slower, it muddies the topic a little because it makes it sound like a fault of the clock. The clock is accurately measuring the time it experiences.
My favourite trivia on this topic is that this is not hypothetical. If the clocks on GPS satellites kept earth time (eg, without accounting for relativistic drift), the entire GPS system would accumulate 10km of error per day. This is a genuine thing with measurable, real-world effects.
Re: Europe pushing for lunar time zone
#264I am a proponent of a Martian timekeeping system where each day has 24 hours 39 minutes and 35.244 seconds and all the rest of time units have standard lengths. For example, at midnight your martian clock would show the time as 24:39:35 for a fraction of a second, then wound back to 00:00:00. The calendar then would track the Earth calendar as close as possible, with shortened months to accommodate for the longer day…
Do you honestly consider modifying the core idea of the 24 hour day to be a "slight tweak"? I can't even imagine how many different things rely on that assumption. (and I'm sorry, but what does "naming months and seasons in Mars" have to do with this?)
Way easier than changing the rotation speed of mars.
Re: Europe pushing for lunar time zone
#265Earlier quoted context omitted.
It's basically the same thing, but harder to achieve technically because many things assume clocks are moving all the time. For example timers and timeouts are frequently implemented as loops polling system time has reached a certain future value. Many things break or malfunction if a large number of things happen at the same time, for example logging, crons etc. Imagine investigating a cybersecurity event perpetrate…
Those things should be on UTC anyway (even on earth). Timezones are just for displaying to humans.
Timers sound like they should be using a monotonic timer actually, so they are not affected by the system clock being adjusted.
Re: Europe pushing for lunar time zone
#266I am a proponent of a Martian timekeeping system where each day has 24 hours 39 minutes and 35.244 seconds and all the rest of time units have standard lengths. For example, at midnight your martian clock would show the time as 24:39:35 for a fraction of a second, then wound back to 00:00:00. The calendar then would track the Earth calendar as close as possible, with shortened months to accommodate for the longer day…
> each day has 24 hours 39 minutes and 35.244 seconds > at midnight your martian clock would show the time as 24:39:35 for a fraction of a second A similar idea could be to have exactly 24h 39min 35s each day (i.e. the last second before midnight is 24:39:34), then add a leap second every 4 days to compensate for the missing 0.244s, then skip it when the 0.006s errors cumulate up to 1s. This just because in my opinio…
Is the difference in quality of life so dramatic with a day wrapping on non-integer seconds when both proposals wrap at non-integer minutes and non-integer hours?
The real question is why stop at miliseconds - it seems inconsequential. Go all the way down and assume that as the hour/minute/second granularity all proved insufficient in the past, the same way milliseconds would become insufficient one day. Make the period parameterizable (i.e. not a constant), with only the current value at 24 hours 39 minutes 35 seconds 244 milliseconds.
Re: Europe pushing for lunar time zone
#267The title is slightly misleading -- strictly speaking, they aren't just giving the moon its own time "zone", they're giving it a reference time.
what's the different exactly @jxf?
A reference time describes what standard of time we use. On Earth, for most human use cases, the reference time is UTC. UTC is measured by using International Atomic Time (TAI, from the French "temps atomique international") and adding or subtracting a prescribed number of leap seconds to account for the rotation of the Earth.
We don't use TAI in everyday use because it's constantly and continuously changing in small ways to account for the tiny accelerations or decelerations in Earth's rotation, and that's annoying for computers. So instead we use UTC.
A time zone is a different thing entirely. A time zone is a set of rules that describes how to convert from a reference time to a local time.
Most people think of a time zone as being a fixed offset, like "I use Eastern Time; that means UTC-5". This is wrong. A time zone is a _set_ of offsets, each of which applies to a _range_ of reference times. For example, we have a time zone called "America/New York". This describes, for any current or future datetime in reference time, what the correct _local_ time would be.
Here the scientists are doing two things: deciding what the UTC equivalent for the Moon should be (the reference time) and deciding what (if any) offsets should be applied to compute "local" time somewhere on the Moon (the time zone).
Re: Europe pushing for lunar time zone
#268[flagged]
Re: Europe pushing for lunar time zone
#269> There are also technical issues to consider. Clocks run faster on the moon than on Earth, gaining about 56 microseconds each day, the space agency said. Further complicating matters, ticking occurs differently on the lunar surface than in lunar orbit. As a programmer, I can feel a migraine coming on just thinking about the bugs this is going to cause.
"Send your compute intensive code into orbit with us! We run faster"
Re: Europe pushing for lunar time zone
#270> There are also technical issues to consider. Clocks run faster on the moon than on Earth, gaining about 56 microseconds each day, the space agency said. Further complicating matters, ticking occurs differently on the lunar surface than in lunar orbit. As a programmer, I can feel a migraine coming on just thinking about the bugs this is going to cause.
Honestly, I hope we will do the obvious thing and adopt a "calendar second" that has a different size everywhere you go on the Solar System.
The alternative is just crazy.