Creating a Fictional Planet’s Calendar

When humans finally manage to colonise another planet, there will be some significant differences between life on that planet and life on Earth.  One of them is the calendar.  Why would the Earth’s calendar be inadequate?

First, the orbital period of the new planet will be different than Earth’s 365.25 days.  Second, the length of the day is going to be different.  Third, with these two basic pieces of information, the year will start at different seasons, and midnight would happen at different times of day.  It would make no sense.

So, what we need to do is create a new calendar and timekeeping system.  I’m going to use my fictional world of Ariadne as an example.  I have yet to figure out the calendar, so I’m doing it on the fly as I write this post.

First of all, we need to determine the distance of the planet from the star, which is Beta Comae Berenices.  To do this, we need an equation.  We’ll start with the equation that is used to determine the temperature of a planet (and rearranged to solve for distance D).

D = (Ts^2Rs/2Tp^2)((1-a)/(1-τ/2))^1/2

D is the distance to the star, Ts is the temperature of the star, Tp is the temperature of the planet, Rs is the radius of the star, a is the albedo of the planet, and τ is the optical depth of the planet’s atmosphere.  Going through this, I want Tp to be equal to 288 Kelvin, which is similar to Earth’s.  The albedo should also be similar to Earth’s which is 0.39.  And the optical depth should be similar to Earth’s, considering the atmosphere is very similar.  Therefore, that should be 0.6.  The temperature of Beta Comae Berenices is 5,935 Kelvin, which is slightly hotter than the sun.  The star is also slightly larger than the sun, 1.106 times the size, and therefore has a radius of 770,154,252 metres.  Plug all these in the equation, and we get a distance of 152,657,589 km, which is slightly larger than the distance of the Earth from the sun.

Now, to determine the orbital period of the planet, we need the mass of the star, the orbital radius, and the mass of the planet.  We’ll use Kepler’s Third Law for this. To simplify this, I used this very handy tool to calculate the period.  The semimajor axis is set to 152,657,589 km, the mass of the planet is 1.028 Earth masses (as it’s 2.8% more massive than Earth), and the mass of Beta Comae Berenices, which is 1.15 times the mass of the sun.

We have a result of 0.961094 Earth years, or 351.046 days.

Now, as for the calendar, I’m going to be making up some numbers a bit here.  I’ll keep the numbers the same for the planet and star, but the year will be 351.1 days.  This means that the day on Ariadne is slightly shorter than Earth’s day by 13 seconds.  That’s all.  For the clock, a standard 24 hour clock with 60 minutes can continue to be used, though it’ll have to be adjusted a little.

As for the calendar, to get a nice round number of days per month is a bit difficult.  However, based on a 351 day year, a 12 month calendar with 29 day months is possible.  There are an extra 3 days, though.  They could be distributed around to 3 other months, but I’d like to do something special.  At the beginning of each year, there will be a 3 day month.  It’ll be a 3 day period for people to celebrate the colonisation of the world.

Now, to account for that extra 0.1 days, we can add leap years every 10 years.  Add an extra day on the decade to the holiday month, so on every 10th anniversary, there’s an extra long holiday.

As the year is slightly shorter, people’s ages will increase a bit faster.  So, a 50 year old person on Earth would have an age of 52 on Ariadne.  It won’t make a big difference, though.  However, colonists will have to figure out a new birthday based on this new calendar.  That can be calculated by regressing the calendar into negative years to find the birthdate.  The landing date will start with year 1, holiday month day 1.

Another matter is to name the months.  This will come at a later date, as the colonists haven’t arrived at the planet yet!  They’ll have time to name them.

I hope you found this post informative.  This is going to be Ariadne’s standard calendar, and it will be described with names in the future.


Book Review – Scavenger’s War

scavengerswarScavenger’s War is the first book of The Marlowe Transmissions by Jack Sheppard.  It’s a short post-apocalyptic science fiction novella that left me with very mixed feelings.

Desmond Marlowe is a man who has been traveling a long time through the former United States, which is now a wasteland populated by pockets of people and the scavengers, a race of part human, part technological beings who prey on people for energy.  There are a few city-states, and Dez is on his way to one of them, Detroit.  Detroit is a fortress ruled by dictator Terrence McHale.  Dez meets his daughter, and everything goes to hell for him.

The story is an interesting take on the post-apocalyptic genre, as there was no war, no alien invasion, no nuclear bomb, no asteroid impact, no disease.  It’s the result of a well-meaning attempt to expand the mind’s abilities.  People have telekinetic abilities, but it has resulted in people thinking they’re invincible, so the world became an anarchy.  War spread and the land was devastated.  This isn’t much of a spoiler, as it’s explained very early on, including in the book’s description.  It was an intriguing idea.  But I felt that there were some aspects that didn’t work for me.

The characters didn’t click with me.  Dez Marlowe seemed like a seasoned veteran of this dark future’s battles.  However, I couldn’t get the image that he was a young man for most of the book.  He was not even described until the final third of the book.  I didn’t know what he looked like or how old he was.  When he was finally described, my image of him was completely wrong.  We didn’t get to see much of Terrence McHale, but his daughter was central to the story.  Layla McHale seemed both spoiled and naive.  But she had to grow quickly.  I felt like I didn’t get enough time to like her.  There was some good characterisation, particularly with Huginn.  I liked him.

The technology is also interesting.  The scavengers seemed almost like animals acting on instinct, with only a remnant of their humanity remaining.  Some of the weapons that relied on mind control were intriguing, too.  The brain and technology interface was all telekinetic, not using a direct physical connection.  I liked that.

This story is told in first person using present tense.  This is a difficult way to write a book, and I found it somewhat jarring.  At one point, this was described as a transmission of Marlowe’s experience.  Wouldn’t he be talking about it in past tense?  I wasn’t sure why it was in present tense.  I’m not a fan of this kind of writing style.  This was the biggest problem for me.  But that’s just my personal taste.

Overall, I felt that this story had potential to be very good.  However, there were many things that didn’t make it as enjoyable as I’d have liked.  I am interested in seeing how it continues, though.  In the end, I have to give this 2 and a half stars out of 5.  Recommended for those who like post-apocalyptic stories with a twist.