hi,

i know the Galactic Standard Calendar

Which is

• 60 seconds = 1 minute
• 60 minutes = 1 hour
• 24 hours = 1 day
• 5 days = 1 week
• 7 weeks = 35 days = 1 month
• 10 months + 3 festival weeks + 3 holidays = 368 days = 1 year

and all the BBY (and other) notations, but i can't figure out how time is passing on different planets.

For example, take two planets A and B, where planet A has a 25h day and planet B has a 20h day.

Let's assume we are at BBY0 Day 1 in the galactic standard calendar (and the time in all the universes and planets are starting right know :D, to provide the same starting conditions). After 22h, planet A has the local Time BBY0, Day 1, 22:00h, whereas planet B has the local date time of BBY0, Day 2, 2:00h?

So after a little time the planets dates are drifting more and more? Is this correct? If not can someone explain me the star wars time ?

I think Star Wars actually handles this concept pretty well with little confusion.

26 minutes ago, Bojanglez said:

I think Star Wars actually handles this concept pretty well with little confusion.

So let's take the galactic standard date BBY56 Day 2, which is equal to BAY23 Day 16 on planet A and equal to BBY77 Day 3 on planet B?

Which means that every planet has it's local date time and and equal galactic standard time?

It's easy.

The fluants here are the hours per day and days per year.

So planet A has 25 hours per day and planet B has 20 hours per day.
That means planet A has 353.28 days per year (or 353 for ease, with leap day every 4 years or so) and planet B has 441.6 days per year (so, leap day every 2nd year?)

In other words, they're all on the same galactic year, but the individual days (and possibly weekdays) are different.
I suspect any larger business would still use both local and galactic time so they could keep track of what time it was at their customers locations.
And I'm very sure there's some sort of automated computer program that let's you determine time of day and day of the week on any of the galaxies known planets.

1 minute ago, OddballE8 said:

It's easy.

The fluants here are the hours per day and days per year.

So planet A has 25 hours per day and planet B has 20 hours per day.
That means planet A has 353.28 days per year (or 353 for ease, with leap day every 4 years or so) and planet B has 441.6 days per year (so, leap day every 2nd year?)

In other words, they're all on the same galactic year, but the individual days (and possibly weekdays) are different.
I suspect any larger business would still use both local and galactic time so they could keep track of what time it was at their customers locations.
And I'm very sure there's some sort of automated computer program that let's you determine time of day and day of the week on any of the galaxies known planets.

I get it, that they are all at the same galactic date, but they have to be on different local years due to the day per year ratio?

After 353.28 days planet A is on year 2 while planet B is still on his local year 1.

So if i understand it correctly, each planet has its own local date and also an equal galactic date?

I think the way it works is there is a standard time/date/year (maybe based off the time at the Senate on Coruscant), which is the official Galactic time. However, planets are going to have their own local calendars and time-keeping methods based on their own orbits and rotations (incidentally, I do wonder how a rotationally locked planet would deal with things such as "days" if the same side is always facing the star), and the two calendars are simply synced.

So let's take Coruscant, Alderaan and Corellia:

Coruscant has a day of 24 standard hours and a year of 368 standard days.

Alderaan also has a day of 24 standard hours and a year of 364 standard days.

Corellia meanwhile has 25 standard hours in a day and a year of only 329 days.

Each place will have its own distinct yearly calendar, with its own distinct timezones within it. However, even if you have City A on Corellia with Corellian date X at time Y, and City B on Corellia with Corellian date X and time Z (as they are in different time zones) both would have the exact same Galactic Standard date and time. In fact, Cities A & B would have the exact same date/time in the Galactic Standard as Cities C & D, which are in different timezones (date U in timezones V & W) on Alderaan.

So even though from their perspectives, City A/C & City B/D are at a different stage in the daily rotation (i.e. have different local times), and the local dates (based on the yearly rotation, so the date would be X on Corellia and U on Alderaan) are a perfectly valid use for internal affairs, anything interplanetary would require a standardised calendar to make things work.

I mean, you see it here on Earth with the Gregorian calendar. If I asked you to meet me 2 hours into the 26th of Av, 5777, you wouldn't have a clue that I was asking to meet you at 22:30 on August the 18th, 2017. Various cultures have had their own methodology for marking time, but for ease the world has adopted one specific calendar to use as standard (with the addition of timezones of course).

Basically, imagine you had colonies built on the Moon, Mars and Callisto. For ease of understanding because of the drastically different years/days, everyone decides to default to using Greenwich Mean Time and the Gregorian date. Even though the people there would probably adopt their own local calendar, the standard would always be the exact same everywhere.

And I have no idea if I've helped at all or just confused you even more...

No you didn't confused me I think i understood how it works

Now i can continue working on my Timetracking Application ^^

Thank you for explaining!

Regarding planets, only years and days have astronomical meaning, the subdivision into months, hours etc are just to make it easier for us to track time.

1 day = time of one revolution of a planet

1 year = time it takes for a planet to orbit its sun (this might be weird for tatooine or other planets with multiple suns)

Thus, since all planets take a different time for their days/years, it's unavoidable that their calendars are out of sync, and the Galactic Standard Calendar is, as mentioned above, more of a Greenwich Mean Time.

Now to give a peculiar example from our solar system, a day on Venus is as long as ~243 earth days, while a Venus year takes only ~225 earth days.

2 hours ago, Dutzen said:

I get it, that they are all at the same galactic date, but they have to be on different local years due to the day per year ratio?

After 353.28 days planet A is on year 2 while planet B is still on his local year 1.

So if i understand it correctly, each planet has its own local date and also an equal galactic date?

Umm, no?

Because both planet A and planet B switch years on the same galactic day.
It's just that it takes 353 local days for Planet A to get there and 441 local days for planet B to get there.

But the year is still the same galactic year.

24 BBY would still be 24 BBY on both planets.
It's just that planet A would experience 353 local days during that year and planet B would experience 441 local days.

42 minutes ago, OddballE8 said:

Umm, no?

Because both planet A and planet B switch years on the same galactic day.
It's just that it takes 353 local days for Planet A to get there and 441 local days for planet B to get there.

But the year is still the same galactic year.

24 BBY would still be 24 BBY on both planets.
It's just that planet A would experience 353 local days during that year and planet B would experience 441 local days.

How?

I assume a minute is a minute and an hour is an hour no matter on which planet you are. So let's take Arda I (343 days per year / 26 hours per day) and Bespin (5110 days per year / 12 hours per day). Both data is from the books

So i takes Arda I 343*26 = 8918 hours to switch to the next year while Bespin needs 5110 * 12 = 61320 hours to switch to the next year.

I agree that both are on the same galactic time but on different local years / days / times.

7 minutes ago, Dutzen said:

How?

I assume a minute is a minute and a day is a day no matter on which planet you are. So let's take Arda I (343 days per year / 26 hours per day) and Bespin (5110 days per year / 12 hours per day). Both data is from the books

So i takes Arda I 343*26 = 8918 hours to switch to the next year while Bespin needs 5110 * 12 = 61320 hours to switch to the next year.

I agree that both are on the same galactic time but on different local years / days / times.

Except those are local days and local years, namely how long it takes for that planet to rotate on its own axis and to revolve around its sun(s).

I can't even imagine how screwed up our time will be if we ever colonize other planets. Everyone will want to follow Earth time for consistency, but they will need to follow local time for daylight, seasons, etc. It would really mess with you.

2 hours ago, Tramp Graphics said:

Except those are local days and local years, namely how long it takes for that planet to rotate on its own axis and to revolve around its sun(s).

Exactly. As mentioned above, within our own solar system, the Venusian day is actually longer than the Venusian year. Then you have planets with odd rotations (say rotation in the same plane as the orbit so "North" is always facing the star and "South" is away), or bodies like the moon where the rotational period is equal to the orbital period so one side will be in eternal day and the other in eternal night.

2 hours ago, Dutzen said:

How?

I assume a minute is a minute and an hour is an hour no matter on which planet you are. So let's take Arda I (343 days per year / 26 hours per day) and Bespin (5110 days per year / 12 hours per day). Both data is from the books

So i takes Arda I 343*26 = 8918 hours to switch to the next year while Bespin needs 5110 * 12 = 61320 hours to switch to the next year.

I agree that both are on the same galactic time but on different local years / days / times.

So taking your Bespin example: 2 Bespin days=1 galactic day, or 1 Bespin day =1/2 Galactic Standard day.

But in the time it takes Bespin to orbit its star (1 Bespin year), 14 Galactic Standard years have gone by (5110 standard days/365).

I think it's also complicated by the fact that references (on Wookiepedia sometimes) use standard days (24 hours) to compute a year, rather than the actual local day length (in this case 12 hours), so depending on the meaning, a Bespin year could be 5110 local days and 2555 standard days, or 4220 local days and 2555 standard days (I can check that if need be?). If it's the former, then 1 Bespin year is only 7 Galactic Standard years.

1 minute ago, Suma99 said:

Exactly. As mentioned above, within our own solar system, the Venusian day is actually longer than the Venusian year. Then you have planets with odd rotations (say rotation in the same plane as the orbit so "North" is always facing the star and "South" is away), or bodies like the moon where the rotational period is equal to the orbital period so one side will be in eternal day and the other in eternal night.

So taking your Bespin example: 2 Bespin days=1 galactic day, or 1 Bespin day =1/2 Galactic Standard day.

But in the time it takes Bespin to orbit its star (1 Bespin year), 14 Galactic Standard years have gone by (5110 standard days/365).

I think it's also complicated by the fact that references use standard days (24 hours) to compute a year, rather than the actual local day length (in this case 12 hours), so depending on the meaning, a Bespin year could be 5110 local days and 2555 standard days, or 4220 local days and 2555 standard days (I can check that if need be?). If it's the former, then 1 Bespin year is only 7 Galactic Standard years.

any given planet's year is based upon local days.

Just now, Tramp Graphics said:

any given planet's year is based upon local days.

It appears that FFG uses local days, but Wookieepedia specifies the Corellian year length as being standard days . It could simply be that it's an error on the part of the wiki editors, as it does make more sense to use local days to calculate local years (but given the difference between a Corellian and standard day is 1 hour it might have been considered to not matter, is not a great way of looking at it).

Given that an hour is an hour is an hour regardless of world you are on in the Star Wars galaxy, then 8832 hours = 1 galactic year. Regardless of planet.

So, to know the galactic time, just measure hours since the 0 point and divide by 8832.

This is basically how time is kept by some operating systems. Unix is just the integer value of seconds since Jan 1, 1970 00:00:00. It just uses math to convert the timestamp to the "local" time of the computer.

- reserved - will post response later.

19 hours ago, Dutzen said:

How?

I assume a minute is a minute and an hour is an hour no matter on which planet you are. So let's take Arda I (343 days per year / 26 hours per day) and Bespin (5110 days per year / 12 hours per day). Both data is from the books

So i takes Arda I 343*26 = 8918 hours to switch to the next year while Bespin needs 5110 * 12 = 61320 hours to switch to the next year.

I agree that both are on the same galactic time but on different local years / days / times.

Again, no.

Arda I takes 343 local days to make a local year. But it only takes 339(.69) days to make a galactic standard year.
And Bespin takes 5110 days to make a local year. But it only takes 736 days to make a galactic standard year.

You're mistaking local years for galactic years.

A local year = the time it takes for the planet to make one revolution around its local star.
A galactic year = 8832 hours no matter where you are. So a galactic year in local days = 8832 divided by the hours per local day. In the case of Bespin, that's 736 (8832 / 12) local days.

In other words, citizens on an imperial (or republic, back in the day) planet do not celebrate "new year" when the planet has made a full revolution around its star, but rather when Corellia has completed one revolution around its star.

Local years might well be celebrated as well, but everything that's even remotely official (such as military, government, business, education etc.) will be on the galactic time when it comes to years, but on local time when it comes to hours, days, weeks and possibly even months.

For ecample, take this .gif as an example of time in our solar system.

Days, weeks and months would be different on each of those planets.
But if you adhere to an Earth centric measurment of years, those planets would switch year whenever the Earth completed one revolution of the sun, no matter how far in their own revolutions they would be.

Is this making any sense to you?

On 8/16/2017 at 0:35 PM, Dutzen said:

...and all the BBY (and other) notations, but i can't figure out how time is passing on different planets.

So after a little time the planets dates are drifting more and more? Is this correct? If not can someone explain me the star wars time ?

Well, Obi-wan Kenobi lived on Tatooine and between Episode III and Episode IV (about 20 years), he aged about 40 years. So time goes by at least double on Tatooine.

Bail Organa barely aged a bit from Episode III to Rogue One (the same time frame). So on Alderaan, time stands still.

Hope that helps!

**** crazy math kids, GET OFF MY LAWN!!!

On 8/16/2017 at 5:45 PM, Edgookin said:

I can't even imagine how screwed up our time will be if we ever colonize other planets. Everyone will want to follow Earth time for consistency, but they will need to follow local time for daylight, seasons, etc. It would really mess with you.

@Edgookin Oh, You mean more so than our current oh so elegant Gregorian calendar that has different days in each month, weekdays that change every single year, and then also changes every 4 years? I think we'll manage.

*Edit: And don't even get me started on The lack of the Metric system in the US!

Timekeeping is like floorplans of ships: This way lies madness

Or

Timekeeping is like underwear and bathrooms: Not important

I think I remember reading that this was why Gene Roddenberry came up with the idea of "Stardates" in Star Trek . It was supposed to be a "generic" time based on galactic rotations and such that could be universally applied whether on Earth, a starship, or another planet. It just meant that 48302.1 might be early morning on one planet, the middle of night-shift on the Enterprise , and a balmy afternoon on Risa!

On 19/08/2017 at 3:53 PM, ThreeAM said:

@Edgookin Oh, You mean more so than our current oh so elegant Gregorian calendar that has different days in each month, weekdays that change every single year, and then also changes every 4 years? I think we'll manage.

*Edit: And don't even get me started on The lack of the Metric system in the US!

Honestly, I dunno how you guys do it! Trying to get my head around Imperial measurements just gives me a migraine!
(Funnily enough, though, if someone asks me my height, I'll say: "6 foot, 1 inch". And if someone gives me a height in centimetres, I have to convert it into feet & inches to "get it". Don't ask me why! 220 lb means nothing to me, but 100 kg absolutely makes sense. )

2 hours ago, Daronil said:

Honestly, I dunno how you guys do it! Trying to get my head around Imperial measurements just gives me a migraine!
(Funnily enough, though, if someone asks me my height, I'll say: "6 foot, 1 inch". And if someone gives me a height in centimetres, I have to convert it into feet & inches to "get it". Don't ask me why! 220 lb means nothing to me, but 100 kg absolutely makes sense. )

I can do distances in metric or Imperial. Heights seem to be given in feet and inches, so I can convert to cm. However, I don't know how many feet or yards are in a mile, but I do know how many kilometres, so I convert from miles to kilometres to feet, which is a horribly clunky way of doing it. I think it's because so often distances are still given in miles rather than kilometres, and heights in feet & inches so you still need to know them.

In terms of mass, volumes and temperatures, I just look confused and cling to my SI units. And my response to Fahrenheit is always to convert to Kelvin because it annoys people (what, if you don't like negative numbers it makes sense, and also having zero as absolute zero also makes sense.)

But seriously. I'm a physics student and I looked at some old worked examples from American physics textbooks and just... no . Nothing matches up. At least in metric/SI units, everything was calculated to be defined by each other.

On 19/08/2017 at 6:53 AM, ThreeAM said:

@Edgookin Oh, You mean more so than our current oh so elegant Gregorian calendar that has different days in each month, weekdays that change every single year, and then also changes every 4 years? I think we'll manage.

*Edit: And don't even get me started on The lack of the Metric system in the US!

Also, yes, the Gregorian calendar is inefficient, but that's the problem with a year being 365 & 1/4 days. One solution was to have 12 months of 28 days and then every four years have a leap month , which admittedly, does keep the calendar fixed to seasons. One solution would be to convert weeks from 7 days to 5 to keep the dates consistent with the days. But a lot of religions use 7-day weeks and I can't see that changing.

Ideally, you could do something similar to having The Kilogram somewhere on Earth, which could be The Clock. i.e. for all interplanetary functions, the date-time is always the value shown on the clock (which could also assist with issues of relativity, which I am not even going to start on because Star Wars is space opera and bringing in any form of relativity is just too much maths).