How late is it? - Mars Edition
Sure! Here’s a detailed article on the Darian Calendar System, formatted in Markdown:
How late is it? - Mars Edition
“How late is it?”. It’s a question no one really thinks about. Have a look on your clock and tell your conversation partner how late it is. Yet we make such a fundamental assumption when answering this: we are on the same planet as every human in history ever has been too.
But what happens when we migrate to Mars?
During the Algebra lecture I had at university, which took about 1.5h, I have read into the strange science of making a calendar. But there has been something really interesting. I read about the Darian Calendar and decided to make a website about it (and a blog post, it seems like).
The Darian Calendar is a proposed calendar system specifically designed for future human settlements on Mars. Created by Thomas Gangale in 1985, it seeks to provide a practical and scientifically accurate method for tracking time on a planet with a radically different orbital and rotational period compared to Earth. A Mars day is a little longer than an earth day. A marsian year is even almost double the duration than a terrestrial year.
Mars has a solar day (called a sol) and a year that differ significantly from Earth’s. A sol is 24 hours, 39 minutes, 35.244 seconds to be exact. 1 Martian year equals about 668.6 sols, or 687 earth days (as a reference, two years would be 730 days).
Earth-centric timekeeping systems would not align well with Martian cycles, making them impractical for daily life on Mars. About every one and a half weeks, 12 o’clock would alternate between being in the middle of the night and the peak of the day.
Structure of the Darian Calendar
The Darian Calendar divides the Martian year into 24 months. Those months alternate between 28 sols (for the odd numbered months e.g. the first month, third month, …) and 27 sols for the even-numbered months.
But, just like here on earth, this doesn’t exactly line up with the martian year, so the calendar introduces leap sols.
Leap Sols and Years
With the current system without leap years, 8.6 sols are remaining to be put somewhere. In the first version of the Darian Calendar, years ending in 1, 2, 4, 5, 7, 8 and 10 (=0) had an extra sol. Yet, this isn’t exactly adding up.
In some further developments of the Darian Calendar, a 53-year or a 1000-year cycle had been introduced.
Weekdays
Because everybody wants to know if the weekend has arrived and if you have to work tommorow, weekdays have been introduced.
The Darian System doesn’t make a change to those, a week is still made of 7 sols. But they have been renamed.
| Terrestial | Darian |
|---|---|
| Monday | Sol Lunae |
| Tuesday | Sol Martis |
| Wednesday | Sol Mercurii |
| Thursday | Sol Jovis |
| Friday | Sol Veneris |
| Saturday | Sol Saturni |
| Sunday | Sol Solis |
| To make a little guess here: I think the “Sol” in each name will soon vanish after the system actually is used. |
Months
Months are just as important as weeks. But we have 24 of them on Mars. Even though at the beginning only the Darian Variant was published, several additions and “translations” or whatever you want to call them have been made.
I personally really like the Chinese translations. The thought of waking up on the 8th Sol of Summer Solstice is quite a funny one. Also it would somehow represent seasons in case we are successful with terraforming.
| No. | Darian | Rotterdam | Utopian | Chinese |
|---|---|---|---|---|
| 1 | Sagittarius | Adir | Phoenix | 火星春分 (Spring Equinox) |
| 2 | Dhanus | Bora | Cetus | 火星清明 (Pure Brightness) |
| 3 | Capricornus | Coan | Dorado | 火星穀雨 (Grain Rain) |
| 4 | Makara | Deti | Lepus | 火星立夏 (Beginning of Summer) |
| 5 | Aquarius | Edal | Columba | 火星小滿 (Grain Buds) |
| 6 | Khumba | Flo | Monoceros | 火星芒種 (Grain in Ear) |
| 7 | Pisces | Geor | Volans | 火星夏至 (Summer Solstice) |
| 8 | Mina | Helimba | Lynx | 火星小暑 (Minor Heat) |
| 9 | Aries | Idanon | Camelopardalis | 火星大暑 (Major Heat) |
| 10 | Mesha | Jowani | Chamaeleon | 火星立秋 (Beginning of Autumn) |
| 11 | Taurus | Kireal | Hydra | 火星处暑 (End of Heat) |
| 12 | Rishabha | Larno | Corvus | 火星白露 (White Dew) |
| 13 | Gemini | Medior | Centaurus | 火星秋分 (Autumn Equinox) |
| 14 | Mithuna | Neturima | Draco | 火星寒露 (Cold Dew) |
| 15 | Cancer | Ozulikan | Lupus | 火星霜降 (Frost’s Descent) |
| 16 | Karka | Pasurabi | Apus | 火星立冬 (Beginning of Winter) |
| 17 | Leo | Rudiakel | Pavo | 火星小雪 (Minor Snow) |
| 18 | Simha | Safundo | Aquila | 火星大雪 (Major Snow) |
| 19 | Virgo | Tiunor | Vulpecula | 火星冬至 (Winter Solstice) |
| 20 | Kanya | Ulasja | Cygnus | 火星小寒 (Minor Cold) |
| 21 | Libra | Vadeun | Delphinus | 火星大寒 (Major Cold) |
| 22 | Tula | Wakumi | Grus | 火星立春 (Beginning of Spring) |
| 23 | Scorpius | Xetual | Pegasus | 火星雨水 (Rain Water) |
| 24 | Vrishika | Zungo | Tucana | 火星驚蟄 (Awakening of Insects) |
Mars o’clock
In addition to the calendar, timekeeping on Mars must adapt to the longer sol. You can either stretch the second and redefine the second so that 86,400 Martian seconds fit into one sol, resulting in about 2% longer seconds or just use Earth seconds and adjust the day to have 88,775 Earth seconds.
The Darian Calendar does not prescribe a particular timekeeping method but is designed to work with either approach. But it has been used in the past.
Mars Rovers usually use the first approach, as you can still use normal tools and program code that are working with a 24h-day.
A funny side project
I made a little fun project on my website: The Darian Clock. It is a page that is displaying the current time and the recalculated Darian Time. It runs completly in your browser, so you could even go offline after you loaded the page (but why would you do that?). Just give it a look.
Further readings:
https://en.wikipedia.org/wiki/Darian_calendar https://en.wikipedia.org/wiki/Timekeeping_on_Mars