Sunday, July 12, 2009

A Calendar for Ceres

Once humans go into space to stay, the Gregorian calendar isn't something they'll necessarily take with them. A timekeeping system based around equinox and solstice and organized for the needs of an agricultural society may not have much more than nostalgic value to the pioneers of Sol, considering that the environments they inhabit will be purely artificial. Depending on the tempo with which space is settled, humanity's new worlds may well ditch Earth's dating system in favor of one which is relevant to them, and not just an apron string binding them across the light-hours to a land that's no longer home.

Ceres is one potential middle-term colonization prospect, given sufficient impetus and sufficiently low launch costs. With a perihelion of 2.54 AUs and a required delta-v of 9.4 km/s from Earth orbit to Ceres orbit, it would probably languish in the shadow of Mars, which is somewhat closer to Earth and has an orbit-to-orbit delta-v of only 5.7 km/s - Hohmann orbits, though. The issues of relative inconvenience go out the window if one has a ship capable of accelerating and decelerating all the way.

Once NASA's Dawn probe arrives there in 2015, a great deal of questions we've currently got on the books about Ceres may well be answered. For one - the question of whether it has underground water ice. That alone would be absolutely vital to any kind of colonization enterprise. Setting down landers without a source of water isn't a colony, or even a caravanserai - it's a dependency of the most base and coarse nature, and I doubt there would be many people who'd pay to have water lobbed across the solar system when those enterprising colonists could have set out instead for Europa or Enceladus. Water is life, remember.

Presuming that Ceres does have water ice, it's sounding to me like the sort of place a fringe colony - presuming it could find enough investors or venture capitalists to pony up the start-up funds - might set up. And once they got there, hey... why not make a new calendar, relevant to their new circumstances, to celebrate their new life?

Ceres' orbital period is a little over four and a half Earth years - 1680.5 days, and the Cererean calendar divides this out into 1,680 twenty-four hour days with a bit left over at the end. The days are grouped into twenty-one months, each eighty days long, and owing to my vision of Ceres as being run along technocratic lines, they are for the most part named after scientists, astronomers, and people relevant to the discovery of Ceres. Here they are:

Dawn, Piazzi, Hirayama, Maskelyne, Dyson, Wolf, Chandrasekhar, Al-Battani, Von Zach, Kirkwood, Messier, Cassini, Hayabusa, Galileo, Herschel, Biederman, Bode, Olbers, Gauss, and Vespers.

One interesting historical synchronicity I found while researching this calendar originally was that Giuseppe Piazzi's first observation of Ceres came on January 1, 1801, the first day of the nineteenth century. This serves as the calendar's zero date, and corresponds to Dawn 1, 0 AC (Anno Cereris). My original notes, which have since been lost in the shuffle, included a formula I kludged together to translate a Gregorian calendar date to a Cererean one, but with this shared starting point it's roughly possible to figure something out.

Very roughly, though, because there's still the issue of that .5 of a day left over. Originally I could have just chopped it off and decreed that, for the purposes of timekeeping, Ceres' year was precisely 1,680 twenty-four hour periods in length. While that would work from an individual perspective, as someone living in Ceres might not care much where exactly the sun was in the sky, this would have left the calendar prone to drifting. I can't see any sense in building a calendar from the ground up and intentionally leaving it unbalanced.

To that end, to fill in the extra time, Ceres has an extra "day" which isn't a day at all. Where the Gregorian calendar jumps smoothly from December 31 to January 1, the Cererean calendar does not similarly transition from Vespers 80 to Dawn 1. Instead, the space between them - 19 hours, 39 minutes, and 21 seconds by my original calculations, although I may have been off - constitutes Year's End. I can imagine this is would be the day when Cerereans drink to excess; think of it as a temporal Vegas, when anything that happens stays there.

Writing out this post, and coming to the slow realization that there are probably a great deal of mathematical shortcomings in it that would blow my brilliant concept to flinders, has made me want to drink to excess myself. Excelsior!

1 comment:

  1. Weirdoinventor11/02/2009 12:23 PM

    But why use 24 hour days? A Ceres day is only 9 hours long. What is the point of giving Ceres it's own calender if you ignore the normal "rhythm" of the planet? I mean, day and night would still effect colonists, a lot more than the seasons probably, especially since Ceres' axial tilt is only 4 degrees while earth has 23 degrees, meaning that Ceresian seasons would be less extreme. 9 hours is ridiculously short, I'll admit that, but they could at last use 27 hour days or something right (or just get used to staying up two night in a row, nobody complaining about night shifts anymore, the perfect 24 uhh 9 hour economy)? Or if you do want to stick with 24 hours, why have 19 hours left at the end? Why not let's say an extra hour in every month? I mean, people tend to complain about daylight saving time...
    All in all I don't see much use in using this calender instead of the Geordian calender. So when the time comes, people will probably pick that calender over this one. Now, if a Ceresian calender is't going to be used ayway, I can have some fun with it too. I'll keep te discovery date as start of the calender, although the first landing could be used too, but that wuld put part of Ceres' known history in the minu years, so date of discovery is more elegat. According to your calculation, a Ceres year contains 40339 hours, 39 minutes and 21 seconds, that's 40339.655833 hours (I like decimals, and so does my calculator). According towikipedia, a Ceres day is 9.074170 hours long. So that would put 4445.547728 Ceres days in a Ceres year. That would mean the calender would be pretty accurate if an extra day would be added ones in every two years, and then one more ones every twentyone years or so, that's about ones every earth century. The hours provide a problem. I don't want to invent Ceres seconds, that would mess up science pretty bad, so that means a Ceres day would just have to be nine hours, 4 minutes and 27.something seconds long, or I'dd have to start adding an extra hour ones every two weeks or so, and that will not work. With over 4000 days in a year, splitting it up in just some months would not make sense, each one would be as long (in local days) as an earth year. Perhaps it could be divided in ten units each containing ten smaller units of about 44 days, that's a bit over two earth weaks, extra long weekends. One thing I do know, when the time comes there will be a lot lot more people with an opinion.
    *Looks up from keyboard* Now that's of my chest: nice site you have here. I'm sorry if thi soundedlike a rant, I just like to think about things as useless as this, and obviously so do you. Prosit.