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Europe pushing for lunar time zone

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Re: Europe pushing for lunar time zone

#381

Post by ted_dunning »

benj111 wrote: post #174
eru wrote: post #168

Earlier quoted context omitted.

In decimal, in general in decimal to write a fractions you need an infinite number of digits (with repetition). We have convenient notation for that repetition. A few special fractions can be written with finitely many digits. Using base 12 or 60 you are in the same situation. If you want elegance, you should cut down on the number of special cases. Hence I would suggest to use a base like 11 or 59. That way more fra…

How does base 11 work for counting on your fingers? Last I checked, most of us have only 10 digits

I use 8 fingers with two thumbs for carrying.

That can be interpreted mathematically or practically.

Re: Europe pushing for lunar time zone

#382

Post by muyuu »

why not just leaving it UTC? it's not like time zones make sense on Earth anymore so why start it? plus there are no Earth-like daylight patterns there that humans could possibly adapt their sleep to, lasting weeks at a time

Re: Europe pushing for lunar time zone

#383

Post by pdonis »

throw0101a wrote: post #360
hn8305823 wrote: post #357

Earlier quoted context omitted.

Nobody is going to be having real-time Zoom calls between Earth and Mars so I'm not sure how in sync it needs to be. It does make sense to at least keep the second the same since that is a critical base SI unit that affects lots of other things. One interesting problem will be that high precision atomic clocks will run at a slightly different rate on the surface of Mars due to the lower gravitational potential, but t…

> Nobody is going to be having real-time Zoom calls between Earth and Mars so I'm not sure how in sync it needs to be. If a contract say "the payment must be received before March 1, 2123", then you have to worry about time syncing between the planets. How fast are fund transfers between planets?

> If a contract say "the payment must be received before March 1, 2123"

Then the contract is incompletely specified. March 1, 2123 according to whose time?

Re: Europe pushing for lunar time zone

#384

Post by yencabulator »

adastra22 wrote: post #379
yencabulator wrote: post #374

Earlier quoted context omitted.

If they run on UTC, and correct for drift like any clock needs to do, what else is there? What conversion, what two systems?

Clock slew is unacceptable for many use cases. For keeping system time on a UNIX server or for astronaut watches, sure. For many other things you need a precise and accurate count of how many micro/nano/pico seconds have passed. You can’t just have one second suddenly be N nanoseconds longer and expect sensitive experiments to not be affected.

If you're just talking about measuring e.g. the duration of an experiment, you don't need to sync to TAI for that.

For matching with TAI timestamps, no two atomic clocks agree with each other exactly anyway -- TAI is an average of some 500 atomic clocks. If you care to that level, you have to correct for your elevation on Earth already. So no matter what you do, if you care enough, you'll end up with some correction factor.

For most practical uses, you don't use an atomic clock, just a good steady oscillator, apply a correction factor to its output if you want to match with some other clock source (convert to TAI, etc), and use feedback like NTP to keep your clock on time. The biggest difference between moon and Earth in that is the latency to authoritative clock.

Re: Europe pushing for lunar time zone

#385

Post by layman51 »

once_inc wrote: post #108
barbazoo wrote: post #68

Earlier quoted context omitted.

Wow, there's clearly pros and cons for both! It's all about compromise and the way it currently works, works for the majority of people that don't even experience the downsides in their day to day life. Like having to coordinate meetings around the world or figuring out what time it is for their friend on the other side of the world. Most people never deal with any of that. They just want it to be 12:00 and bright ou…

I've literally heard nobody say they want it to be 12.00 and bright out when they eat lunch, only that they want it to be bright out. Suppose we set the universal time to the current -12h meridian. Everyone works with that exact same time. If I receive a scheduled meeting at 15.00 I know exactly when to be there (wow, that's late for me!). If glance at the clock and see that it is 4.00, I know it's time for my aftern…

Your comment makes me understand why people would want to abolish time zones. However, my issue with that is that I think it would cause confusion when people in everyday life use the word “afternoon”. I won’t know if they’re talking about the time when the sun is getting lower in the sky, or if they are talking about when it is past 12:00 on whatever clock we are mandated to read. We would all need to ask people to clarify those things, especially if they don’t have the detail-oriented mindset for these kinds of things. Now, granted, you do already have to clarify these things when you are speaking with people around the world already.

Re: Europe pushing for lunar time zone

#386

Post by TeMPOraL »

Tor3 wrote: post #347
wasmitnetzen wrote: post #299

Earlier quoted context omitted.

Is this the norm for those people too, or are you basically the only one they ever talk to where timezone matters?

They do indeed talk to people in other timezones as well. We may have online meetings sometimes, with at least three timezones involved. I can't see how one would only contact in touch with people in a single timezone, unless one only wants to have contact with people in continental Europe (excluding e.g. Portugal and Finland), or people in a single timezone in the US. Timezones are everywhere. The earth is a sphere,…

If your work involves coordinating across timezones daily, you're part of the small minority cases I was talking about. Offline world is still mostly local, and almost all interactions almost everyone has, online and offline, are local too.

Re: Europe pushing for lunar time zone

#387

Post by wahern »

cornholio wrote: post #246
planede wrote: post #218

Earlier quoted context omitted.

They really should have been on TAI. I guess it doesn't matter now if we won't get any more leap seconds.

It's worth noting that even atomic clocks run on Mars faster than on Earth, due to the different gravity. So you might expect say half of the 50 microsecond daily gain quoted in this article for the Moon, 10 miliseconds per year or a full second per century, more than enough to make you your spaceship completely miss its intended orbit. And martians will definitely want to run their own atomic clocks, making sync ver…

> It's worth noting that even atomic clocks run on Mars faster than on Earth, due to the different gravity.

The biggest effect is the Sun's gravity, followed by orbital velocity. The relative masses of the planets is negligible by comparison, though in online discussions that's almost all anybody ever seems to talk about.

I can't find confirmation through other sources, and can't credibly validate it myself, but the best estimate I found for time dilation between two clocks on Earth and Mars is roughly 5.6 parts per billion, or ~177 milliseconds per year. See https://space.stackexchange.com/questions/33590/what-is-the-...

Re: Europe pushing for lunar time zone

#388

Post by quickthrower2 »

benj111 wrote: post #184
quickthrower2 wrote: post #167

Earlier quoted context omitted.

Your heart rate then becomes unitless

Beats per beat? I can think of more confusing language constructs. Plus acceleration is metres per second per second and that isn't unitless. One solution though would be to make use of one of the freed up words and use minute instead of beat. So we could say minutes per beat. Does that deal with your concern?

If you pronounce it my-newt then I am happy with this

Re: Europe pushing for lunar time zone

#389

Post by Tor3 »

TeMPOraL wrote: post #386
Tor3 wrote: post #347

Earlier quoted context omitted.

They do indeed talk to people in other timezones as well. We may have online meetings sometimes, with at least three timezones involved. I can't see how one would only contact in touch with people in a single timezone, unless one only wants to have contact with people in continental Europe (excluding e.g. Portugal and Finland), or people in a single timezone in the US. Timezones are everywhere. The earth is a sphere,…

If your work involves coordinating across timezones daily, you're part of the small minority cases I was talking about. Offline world is still mostly local, and almost all interactions almost everyone has, online and offline, are local too.

Firstly, that's not a small minority case, and secondly, in my small town there are people from around 100 nations, and they have family and friends from all over. And, as I said, even central Europe has 3 timezones just inside EU. It's not like most people only have contact with their 50 neighbours, and never go anywhere. When I talk with friends, timezones come up reasonably often. It's not something people can walk around and not be aware of.

Re: Europe pushing for lunar time zone

#390

Post by cornholio »

jjk166 wrote: post #376
wmanley wrote: post #290

Earlier quoted context omitted.

and the minute hand?

Still goes at 1 rotation per hour. You put the minute markings on another wheel to precess each day. The hour and minute hands won't form the same angle at the same time each day, but it will still tell the correct time.

The problem is, what do you do at 24:39:35, when both the minute and the second arm have more than a third of the way to go before zero?

Any mechanical design where units are not cleanly divisible would have to devise a way for the arms to "fast forward" over the gap and accept nonsensical results for a few seconds before midnight.

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