Science Changes to the world's time scale debated.

[T.Neo]

I'm not advocating 100 kilosecond days for any other situation than such space colonies (and maybe as a standard for ships in transit as well).

I still don't get the point of it though. If you have seconds lying around, why not just define a day as ~86 seconds? It does not have to be a round number, just like a whole number of other things.

A hundred kiloseconds is nearly four hours longer than a day. Small enough of a difference to adapt to? Most likely. Small enough to be nontrivial in any and all respects? That's another matter.

Nor can you arbitrarily grow or shrink on a whim. If you could (within certain limits) you might round yourself off to one meter (or two) if it did away with the need to make certain calculations in every day life.

I don't think I've ever had to calculate anything special either when looking at a clock or measuring my height...

When there is no such relevant measurement, such as when you're living in a space colony far from any inhabited planet, and the 10 nearest planets have 10 different day lengths based on their own day/night cycles, but you get to choose when to turn your lights on and off, why not slip in to a nice round 100 kilosecond schedule?

Or why not use the most relevant day length instead of a silly number?

Like for example the day length most people on the colony or visting it would be accustomed to. Or the day length of the nearest or most influential planet nearby. Or an average based on a group of nearby planets.

Mind you, in our solar system, objects that have rotation periods relevant in 'day' terms are pretty few and far between...

There's only really Earth and Mars, no? And not many where sunrise and sunset matter that much to you (though perhaps to your equipment).

Which is why a convenient value for the "day" in situations where a planetary environment doesn't define it for you is 100 kiloseconds.

I know another convenient value for "day". It's called a "day"...

Of course, the really messy situation would be when you *do* have a planetary environment, and it throws a week-long day at you.

Yeah, that would be a problem. But generally in our solar system, you get either bodies that have day-like rotation rates (and are rare) or have very long rotation rates (and thus leave you to create your own day/night cycle for human relevance). Or you get bodies that are so inhospitable (but this is normal and common, mind you) that the "time of day" is completely irrelevant.

I think there are several moons in the outer solar system that have day-like rotation rates.

 

[Quick_Nick]

Point: No matter what you do, you're never going to have a system that meets everyone's needs. I can't say that any tradeoff is better than any other. The sanity of ANY of these standards is marginal.

 

[Jarvitä]

Do you see any tidally locked planets around here?

Depending on your definition of "here", I could name plenty.

I don't. I see even fewer people living on them.

I don't see how that is relevant to the point that telling solar (stellar) time is impossible on them.

 

[T.Neo]

Depending on your definition of "here", I could name plenty.

Perhaps we should start with planets/bodies that our technology actually enables us to study meaningfully. :dry:

Or ones that we can actually stage meaningful missions to...

I don't see how that is relevant to the point that telling solar (stellar) time is impossible on them.

There is still libration. And you could also potentially measure the change in angular diameter caused by differing distance along an eccentric orbit...

 

[Jarvitä]

Perhaps we should start with planets/bodies that our technology actually enables us to study meaningfully. :dry:

Or ones that we can actually stage meaningful missions to...

Why are you always so content to limit yourself to the present? The SI system is still in use precisely because it's so future-proof. And the only SI unit of time is the second, defined in terms of radiation periods of the caesium 133 atom.

There is still libration. And you could also potentially measure the change in angular diameter caused by differing distance along an eccentric orbit...

Which has precisely zero relevance to your original statement that there are currently no humans on them.

 

[T.Neo]

Why are you always so content to limit yourself to the present?

Perhaps you should be asking: why I am so content not to start to ignore reality for fantastical notions of the future.

The SI system is still in use precisely because it's so future-proof. And the only SI unit of time is the second, defined in terms of radiation periods of the caesium 133 atom.

Really? Because I see a table on Wikipedia that says "accepted for use with the SI", under which says (among other assorted measurements), day, hour, and minute. Now, that is Wikipedia of course, and I don't know who edited that table, and "accepted for use with" does not mean "part of", but perhaps does stretch the validity of "only" unit of time.

What defines the second is meaningless from the point that it was not created of that definition. A second is a second because it is one 86 400th of a day. From that point of view it is a completely arbitrary measure of time. I could split days up into 10 000ths or 1000ths or 7000ths and define the resultant measures of time in radiation periods of cesium-133.

And so far I am not entirely sure that the SI is in use because it is "future proof", but rather because it is an internally consistent and easy to use system of measurement. That said, I don't think I've seen kilo- or megaseconds catch on as popular units of time.

Which has precisely zero relevance to your original statement that there are currently no humans on them.

I would hope that it has quite a good deal of relevance to your statement that telling stellar time on a tidally locked planet is impossible.

And the fact that there are no people (that we know of) on tidally locked planets to tell time there, is pretty important in any discussion of telling time on tidally locked planets (unless the existence of such residents is presupposed as part of a speculative excersise).

 

[Arrowstar]

Wrong. GPS does actually transmit the number of leap seconds that apply since 1980 (It does so every 12.5 minutes, together with ionospheric information). But the GPS time signal for synchronization is without such leap seconds, it is pure atomic time.

Ah, okay. I think I was looking at the atomic time signal and not considering true GPS time. Thank you for clarifying!

 

[Notebook]

Todays the Day! or Second...

Time experts debate whether to abolish the leap second

http://www.bbc.co.uk/news/science-environment-16597191

N.

 

[Face]

I'm curious what they will come up with.

If the leap second is really dropped, I'd rather see a time zone addition instead of a leap hour. I.e., UTC is technically unaltered, but "human time" offset is added to time zones, so e.g. ZULU is not equal to UTC anymore, but adds the accumulated leap seconds/minutes. Converting local time to other time zones would then not be harder than now (add/sub full hours), just the reference check has added granularity.

For applications, the human time is a visualization problem, anyway. Heck, humans can't even agree on the order of month and day in their date strings. I don't get why visualization details need to be incorporated into reference data in this case. Despite it been done in the past...

regards,
Face

 

[werdna]

Come on guys, just use a sundial!

 

[Face]

Come on guys, just use a sundial!

So... you don't have a Stonehenge in your backyard? Tststs...

 

[Mojave]

Why can't we just leave our time scale alone?

 

[Grover]

because that would cause us to be possibly out by a half day in the far future. imagine waking up one day at 8AM to find that the sun had already set, would be kinda wierd dont you think

 

[PeriapsisPrograde]

You know, there was a day when; when I woke up, it was morning; when I ate lunch, it was noon; when I went to bed, it was night. Why the heck do we need to attach a number to it?
:2cents:

 

[T.Neo]

You know, there was a day when; when I woke up, it was morning; when I ate lunch, it was noon; when I went to bed, it was night. Why the heck do we need to attach a number to it?

Ever had to be at an appointment at a certain time?

 

[Notebook]

Well fancy that...:

http://www.bbc.co.uk/news/science-environment-16625614

The ITU suggested that a study group should investigate the issue, before presenting any proposals at the next World Radio Conference in 2015.

Nicely fobbed off.

N.

 

[Mojave]

Just don't bace time off the sun. Bace it on just numbers. Who cares if it's day or night?

 

[Keatah]

Why should precision stuff run on civilian time?
GPS satellites can run on the straight time, nobody checks their clocks by them.

Cellular phone base-station timebases are derived from GPS or from the same standard as gps. I will also guess(but not sure) that a lot of network timing (think internet) is based off of GPS or its parent.

 

[T.Neo]

Just don't bace time off the sun. Bace it on just numbers. Who cares if it's day or night?

I do, because I actually live in the real world, I actually have a circadian rythm, and I sure as Mercury don't want to have to go to sleep while the sun is blaring outside my window.