Architect of Worlds – Step Nineteen: Determine Blackbody Temperature

September 20, 2020 Sharrukin Comments 2 comments

The blackbody temperature of a world is the average surface temperature it would have if it were an ideal blackbody, a perfect absorber and radiator of heat. Real planets are not ideal blackbodies, so their surface temperatures will vary from this ideal, but the blackbody temperature is a useful tool for determining a variety of other surface conditions.

In particular, the blackbody temperature is useful in determining what atmospheric gases the world can retain over billion-year timescales. Simple thermal escape (also called Jeans escape) isn’t the only mechanism by which a world can lose atmospheric gases, but it is a strong influence on the stable mass and composition of the atmosphere.

In this step, we will compute the blackbody temperature and the M-number for the world under development. The M-number is equal to a minimum molecular weight that can be retained over long timescales.

Procedure

To determine the blackbody temperature for a world, evaluate the following:

$T=278\times\frac{\sqrt[4]{L}}{\sqrt R}$

Here, L is the current luminosity of the primary star in solar units, R is the orbital radius of a planet (or the planet that a satellite orbits) in AU, and T is the blackbody temperature in kelvins. Note that the blackbody temperature will be the same for a planet and all of its satellites.

To estimate the M-number for a world, evaluate the following:

$M=\ 676300\ \times\frac{T}{K\times R^2}$

Here, T is the blackbody temperature, K is the world’s density compared to Earth, R is the world’s radius in kilometers, and M is the M-number. Round the result up to the nearest integer.

Example

Alice computes the blackbody temperature and the M-number for Arcadia IV and Arcadia V:

World	Orbital Radius	Mass	Density	Radius	Blackbody Temperature	M-Number
Arcadia IV	0.57 AU	1.08	1.04	6450 km	281 K	5
Arcadia V	0.88 AU	0.65	0.92	5670 km	226 K	6

Comparing both planets to Earth (with a blackbody temperature of 278 K and an M-number of 5), Alice finds that both of these worlds are somewhat Earthlike. Arcadia IV is just a little warmer than Earth, while Arcadia V is significantly colder.

Both worlds seem likely to have atmospheres broadly similar to that of Earth. An M-number of 5 or 6 indicates that a planet can easily retain gases such as water vapor (molecular weight 18), nitrogen (molecular weight 28), oxygen (molecular weight 32), and carbon dioxide (molecular weight 44) against simple thermal escape. It’s possible that other factors will impact the atmospheres of these worlds, but for now, Alice is satisfied that she still has two somewhat hospitable environments to use in her stories.

Dependencies in a Model

September 17, 2020 Sharrukin Comments 5 comments

Still working on the next sections of Architect of Worlds.

What’s interesting is that we’re coming to a number of items that fall into a web of dependencies. Some items affect the most likely outcome of others, and it’s not a nicely linear process. Just to give you a sample, here’s some storyboarding I’ve been doing using the Miro application online:

Where this mostly comes into play is with the order that the steps need to come in the design sequence. Fortunately, I have yet to come across any dependency loops. As long as the sequence moves more or less left to right, everything should work properly . . .

Architect of Worlds – Step Eighteen: Local Calendar

September 15, 2020 Sharrukin Comments 0 Comment

In this step, we will determine elements of the local calendar on the world being developed: the length of the local day, the length of any “month” determined by a major satellite, and so on.

Length of Local Day for a Planet

To determine the length of a planet’s day – the planet’s rotation period with respect to its primary star rather than with respect to the distant stars – compute the following:

$T=\frac{P\times R}{P-R}$

Here, P is the planet’s orbital period as determined in Step Fifteen, while R is the planet’s rotational period as determined in Step Sixteen, both in hours. T is the apparent length of the planet’s day, also in hours.

Note that this equation is undefined in cases when the orbital period and rotational period are equal (that is, the planet is in a spin-orbital resonance of 1:1 and is “tide locked”). In this case, the length of the local day is effectively infinite – the sun never moves in the sky!

At the other extreme, if the orbital period is much longer than the rotational period, then the day length and the rotational period will be very close together.

To determine the length of the local year in local days, simply divide the planet’s orbital period by the length of the local day as computed above.

Length of Apparent Orbital Period for a Satellite

To determine the length of a satellite’s orbital period, from any position on the planet’s surface, use the same equation:

$T=\frac{P\times R}{P-R}$

Here, P is the satellite’s orbital period as determined in Step Fifteen, while R is the planet’s rotational period as determined in Step Sixteen, both in hours. T is the apparent length of the satellite’s orbital period, also in hours.

Again, this equation is undefined in cases when the satellite’s orbital period and the planet’s rotational period are equal (that is, the planet is tide-locked to its satellite, or the satellite happens to orbit at a geosynchronous distance). In this case, the length of the satellite’s apparent orbital period is effectively infinite – the satellite never moves in the sky.

At the other extreme, if the satellite’s orbital period is much longer than the planet’s rotational period, then the apparent orbital period and the rotational period will be very close together. Earth’s moon is a familiar example – its apparent motion in the sky is dominated by Earth’s rotation.

It’s possible for a satellite’s orbital period to be shorter than the planet’s rotational period. For example, a moonlet that orbits very close is likely to fall into this case. The apparent orbital period will therefore be negative, indicating that the satellite appears to move backward over time. The satellite will rise in the west and set in the east.

Length of Synodic Month for a Satellite

To determine the length of a satellite’s synodic month, use the same equation once more:

$T=\frac{P\times R}{P-R}$

Here, P is the planet’s orbital period as determined in Step Fifteen, while R is the satellite’s orbital period as determined in Step Fifteen, both in hours. T is the length of the satellite’s synodic month.

It’s very unlikely for a satellite to have the same orbital period around its planet as the planet does around its primary star, so the undefined or negative cases almost certainly will not occur. T will indicate the period between (e.g.) one “full moon” and the next, as observed from the planet’s surface.

Examples

Arcadia IV has no satellite, so the only item of interest will be the length of its local day. Alice computes:

$T=\frac{4170\times22.5}{4170-22.5}\approx22.62$

The local day on Arcadia IV is only slightly longer than its rotation period. Alice can also determine the length of the local year in local days, by dividing the orbital period by this day length. Arcadia IV has a local year of about 184.35 local days.

Arcadia V has a satellite, so that satellite’s apparent orbital period and synodic month might be of interest. For the apparent orbital period, Alice computes:

$T=\frac{16.4\times34}{16.4-34}\approx-31.68$

Arcadia V’s moonlet appears to move retrograde or “backwards” in the sky, rising in the west and setting in the east, with an apparent period of about 31.7 hours.

Meanwhile, for the synodic month, Alice computes:

$T=\frac{7990\times16.4}{7990-16.4}\approx16.43$

The satellite’s synodic month – the period between “full moon” phases – is much shorter than its apparent orbital period. From the surface of Arcadia V, the moonlet will appear to move slowly through the sky, its phase visibly changing as it moves, passing through almost a complete cycle of phases before setting once more in the east. Very strange, for human observers accustomed to the more sedate behavior of Earth’s moon!

Where to Find “Architect of Worlds”

September 15, 2020 Sharrukin Comments 4 comments

Just a quick post today, while I continue to work on the next few steps of the Architect of Worlds design sequence. I’m noticing some renewed interest in this project, which I suppose shouldn’t surprise me given that I’m finally getting back to work on it.

It looks as if people are coming to the blog and doing a tag-search for old Architect of Worlds posts. That’s fine, but you should be aware that the earlier steps as originally posted to the blog may not be the most current version of the system. Not to mention, the blog posts aren’t always formatted so as to be easy to read or use.

For the time being, I maintain PDFs of the current “official” version of the draft on the Architect of Worlds page in the sidebar. If you’re interested in what’s been developed so far, you might want to look there rather than try to page through the old blog posts.

So long as everyone respects my copyrights, you’re welcome to download copies for your personal use. That will probably change as the book gets closer to actual publication, but that won’t be for some time yet. Of course, if you work with the system and get some interesting results, I’d be pleased to hear about that.

Architect of Worlds – Step Seventeen: Determine Obliquity

September 14, 2020 Sharrukin Comments 2 comments

The obliquity of an object is the angle between its rotational axis and its orbital axis, or equivalently the angle between its equatorial plane and its orbital plane. It’s often colloquially called the axial tilt of a moon or planet. Obliquity can have significant effects on the surface conditions of a world, affecting daily and seasonal variations in temperature.

Procedure

Begin by noting the situation the world being developed is in: is it a major satellite of a planet, a planet with its own major satellite, or a planet without any major satellite? Notice that these three cases exactly parallel those in Step Sixteen.

First Case: Major Satellites of Planets

Major satellites of planets, as placed in Step Fourteen, will tend to have little or no obliquity with respect to the planet’s orbital plane. To determine the obliquity of such a satellite at random, roll 3d6-8 (minimum 0) and take the result as the obliquity in degrees.

Note that the major satellites of gas giants, distant from their primary star, may be an exception to this general rule. For example, in our own planetary system, the planet Uranus is tilted at almost 90 degrees to its orbital plane. Its satellites all orbit close to the equatorial plane of Uranus, so their orbits are also at a large angle, and their obliquity is very high. Cases like this are very unlikely for the smaller planets close to a primary star – tidal interactions will tend to quickly “flatten” the orbital planes of any major satellites there.

Second Case: Planets with Major Satellites

A Leftover Oligarch, Terrestrial Planet, or Failed Core which has a major satellite is likely to have its obliquity stabilized by the presence of that satellite.

To select a value of the planet’s obliquity at random, roll 3d6. Add the same modifier that was computed during Step Sixteen for the Rotation Period Table, based on the degree of tidal deceleration applied by the major satellite. Refer to the Obliquity Table.

Obliquity Table
Modified Roll	Obliquity
4 or less	Extreme (see Extreme Obliquity Table)
5	48 degrees
6	46 degrees
7	44 degrees
8	42 degrees
9	40 degrees
10	38 degrees
11	36 degrees
12	34 degrees
13	32 degrees
14	30 degrees
15	28 degrees
16	26 degrees
17	24 degrees
18	22 degrees
19	20 degrees
20	18 degrees
21	16 degrees
22	14 degrees
23	12 degrees
24	10 degrees
25 or higher	Minimal (3d6-8 degrees, minimum 0)

Feel free to adjust a result from this procedure to any value between the next lower and next higher rows on the table.

If the result is Extreme, the obliquity is likely to be anywhere from about 50 degrees up to almost 90 degrees. To select a value at random, roll 1d6 on the Extreme Obliquity Table.

Extreme Obliquity Table
Roll (1d6)	Obliquity
1-2	50 degrees
3	60 degrees
4	70 degrees
5	80 degrees
6	98-3d6 degrees, maximum 90

Again, feel free to adjust a result from this procedure to any value between the next lower and next higher rows on the table.

Third Case: Planets Without Major Satellites

A Leftover Oligarch, Terrestrial Planet, or Failed Core which has no major satellite will be most affected by its primary star.

However, without the stabilizing presence of a major satellite, the planet’s obliquity is likely to change more drastically over time. Minor perturbations from other planets in the system may lead to chaotic “excursions” of a planet’s rotation axis. For example, although at present the obliquity of Mars is about 25 degrees (comparable to that of Earth), some models predict that Mars undergoes major excursions from about 0 degrees to as high as 60 degrees over millions of years.

To select a value for obliquity at random, begin by rolling 3d6 on the Unstable Obliquity Table.

Unstable Obliquity Table
Roll (3d6)	Modifier
7 or less	Roll 1d6 – High Instability
8-13	No modifier
14 or higher	Roll 5d6 – High Instability

Make a note of any result indicating High Instability for later steps in the design sequence. The planet is likely to be undergoing drastic climate changes on a timescale of millions of years.

Now make a roll on the Obliquity Table, but if High Instability was indicated, roll 1d6 or 5d6 on this table, rather than the usual 3d6. Finally, add the same modifier that was computed during Step Sixteen for the Rotation Period Table, based on the degree of tidal deceleration applied by the primary star. Refer to the Obliquity Table, and possibly the Extreme Obliquity Table, as required.

Examples

Both Arcadia IV and Arcadia V are planets without major satellites, so they both fall under the third case in this section, as they did in Step Sixteen.

For Arcadia IV, Alice begins by rolling a 4 on the Unstable Obliquity Table, indicating that she will need to roll 1d6 rather than 3d6 on the Obliquity Table. That roll will therefore be 1d6+1, and Alice gets a final result of 3. Arcadia IV apparently has extreme obliquity in the current era. Rather than roll at random, Alice selects a value for the planet’s obliquity of about 58 degrees.

Alice makes a note of the “high instability” of the planet’s obliquity. Its steep axial tilt may be a relatively recent occurrence, taking place over the last few million years. Arcadia IV, the Earth-like candidate in her planetary system, will have very pronounced seasonal variations, and may be undergoing an era of severe climate change. Any native life has probably been significantly affected, and human colonists would need to adapt!

Meanwhile, for Arcadia V, Alice rolls a 12 on the Unstable Obliquity Table, indicating that the planet’s rotational axis is currently relatively stable. She rolls an unmodified 3d6 on the Obliquity Table, getting a result of 15. She selects a value for this planet’s obliquity of about 28.5 degrees.

Architect of Worlds – Step Sixteen: Determine Rotation Period

September 9, 2020 Sharrukin Comments 0 Comment

A quick note before I drop the next section of the draft: I caught myself making several errors in the mathematics while developing this step. I think I’ve weeded all of those out, but if anyone is experimenting with this material as it appears, let me know if you come across any odd results.

Step Sixteen: Determine Rotation Period

The next three steps in the sequence all have to do with planetary rotation. Every object in the cosmos appears to rotate around at least one axis, and in fact some objects appear to “tumble” by rotating around more than one.

Planets and their major satellites usually have simple rotation, spinning in the same direction as their orbital motion, around a single axis that is more or less perpendicular to the plane of their orbital motion. There are, of course, a variety of exceptions to this general rule.

In this step, we will determine the rotation period of a given world. In this case, we will be dealing with what’s called the sidereal period of rotation – the time it takes for a world to rotate once with respect to the distant stars.

Worlds appear to form with wildly varying rotation periods, the legacy of the chaotic processes of planetary formation. However, many worlds will have been affected by tidal deceleration applied by the gravitational influence of nearby objects. Tidal deceleration may cause a world to be captured into a special status called a spin-orbital resonance, in which the world’s orbital period and its rotational period form a small-integer ratio.

Procedure

Begin by noting the situation the world being developed is in: is it a major satellite of a planet, a planet with its own major satellite, or a planet affected primarily by its primary star?

First Case: Major Satellites of Planets

Major satellites of planets, as placed in Step Fourteen, will almost invariably be in a spin-orbit resonance state. Most models of the formation of such satellites suggest that they are captured into such a state almost immediately after their formation.

Since a major satellite’s orbit normally has very small eccentricity, the spin-orbit resonance will be 1:1. The satellite’s rotation period will be exactly equal to its orbital period.

Second Case: Planets with Major Satellites

A Leftover Oligarch, Terrestrial Planet, or Failed Core which has a major satellite may be captured into a spin resonance with the satellite’s orbit. This is actually somewhat unlikely; for example, Earth is not likely to become tide-locked to its own moon within the lifetime of the sun. However, a satellite’s tidal effects on the primary planet will tend to slow its rotation rate.

To estimate the probability that a planet has become tide-locked to its satellite, and to estimate its rotation rate if this is not the case, begin by evaluating the following:

$T={10}^{25}\times\frac{M_S^2\times R^3}{A\times M_P\times D^6}$

Here, A is the age of the star system in billions of years. M_S and M_P are the mass of the satellite and the planet, respectively, in Earth-masses. R is the radius of the satellite, and D is the radius of the satellite’s orbit, both in kilometers.

If T is equal to or greater than 2, the planet is almost certainly tide-locked to its satellite. Its rotation period will be exactly equal to the orbital period of the satellite.

Otherwise, to generate a rotation period for the planet at random, multiply T by 12, round the result to the nearest integer, add the result to a roll of 3d6, and refer to the Rotation Period Table.

Rotation Period Table
Modified Roll (3d6)	Rotation Rate
3	4 hours
4	5 hours
5	6 hours
6	8 hours
7	10 hours
8	12 hours
9	16 hours
10	20 hours
11	24 hours
12	32 hours
13	40 hours
14	48 hours
15	64 hours
16	80 hours
17	96 hours
18	128 hours
19	160 hours
20	192 hours
21	256 hours
22	320 hours
23	384 hours
24 or higher	Resonance Established

Feel free to adjust a result from this procedure to any value between the next lower and next higher rows on the table.

The planet will be tide-locked to its satellite on a result of 24 or higher, or in any case where the randomly generated rotation rate is actually longer than the satellite’s orbital period. In these cases, again, its rotation period will be exactly equal to the orbital period of the satellite.

Third Case: Planets Without Major Satellites

A Leftover Oligarch, Terrestrial Planet, or Failed Core which has no major satellite may be captured into a spin-orbit resonance with respect to its primary star. Even if this does not occur, solar tides will tend to slow the planet’s rotation rate.

To estimate the probability that such a planet has been captured into a spin-orbit resonance, and to estimate its rotation rate if this is not the case, begin by evaluating the following:

$T={(9.6\ \times10}^{-14})\times\frac{M_S^2\times R^3}{{A\times M}_P\times D^6}$

Here, A is the age of the star system in billions of years, M_S is the mass of the primary star in solar masses, M_P is the mass of the planet in Earth-masses, R is the radius of the planet in kilometers, and D is the planet’s orbital radius in AU.

Again, if T is equal to or greater than 2, the planet has almost certainly been captured in a spin-orbit resonance. Otherwise, to generate a rotation period for the planet at random, multiply T by 12, round the result to the nearest integer, add the result to a roll of 3d6, and refer to the Rotation Period Table. The planet will be in a spin-orbit resonance on a result of 24 or higher, or in any case where the randomly generated rotation rate is actually longer than the planet’s orbital period.

Planets captured into a spin-orbit resonance are not necessarily tide-locked to their primary star (or, in other words, the resonance is not necessarily 1:1). Tidal locking tends to match a planet’s rotation rate to its rate of revolution during its periastron passage. If the planet’s orbit is eccentric, this match may be approximated more closely by a different resonance. To determine the most likely resonance, refer to the Planetary Spin-Orbit Resonance Table:

Planetary Spin-Orbit Resonance Table
Planetary Orbit Eccentricity	Most Probable Resonance	Rotation Period
Less than 0.12	1:1	Equal to orbital period
Between 0.12 and 0.25	3:2	Exactly 2/3 of orbital period
Between 0.25 and 0.35	2:1	Exactly 1/2 of orbital period
Between 0.35 and 0.45	5:2	Exactly 2/5 of orbital period
Greater than 0.45	3:1	Exactly 1/3 of orbital period

On this table, the “most probable resonance” is the status that the planet is most likely to be captured into over a long period of time. It’s possible for a planet to be captured into a higher resonance (that is, a resonance from a lower line on the table) but this situation is unlikely to be stable over billions of years.

Examples

Both Arcadia IV and Arcadia V are planets without major satellites, so they both fall under the third case in this section. The most significant force modifying their rotation period will be tidal deceleration caused by the primary star.

The age of the Arcadia star system is about 5.6 billion years. Arcadia IV has mass of 1.08 Earth-masses and a radius of 6450 kilometers. Alice computes T for the planet and ends up with a value of about 0.083. Arcadia IV is probably not in a spin-orbit resonance, but tidal deceleration has had a noticeable effect on the planet’s rotation. Alice rolls 3d6+1 for a result of 11 and selects a value slightly lower than the one from that line of the Rotation Period Table. She decides that Arcadia IV rotates in about 22.5 hours.

Meanwhile, Arcadia V has mass of 0.65 Earth-masses and a radius of 5670 kilometers. Alice computes T again and finds a value of about 0.007. (Notice that the amount of tidal deceleration is very strongly dependent on the distance from the primary.) Alice rolls an unmodified 3d6 for a value of 12, this time selecting a value slightly higher than the one from the table. She decides that Arcadia V rotates in about 34.0 hours.

Citations

Gladman, Brett et al. (1996). “Synchronous Locking of Tidally Evolving Satellites.” Icarus, volume 122, pp. 166–192.

Makarov, Valeri V. (2011). “Conditions of Passage and Entrapment of Terrestrial Planets in Spin-orbit Resonances.” The Astrophysical Journal, volume 752 (1), article no. 73.

Peale, S. J. (1977). “Rotation Histories of the Natural Satellites.” Published in Planetary Satellites (J. A. Burns, ed.), pp. 87–112, University of Arizona Press.

Architect of Worlds – Step Fifteen: Determine Orbital Period

September 8, 2020 Sharrukin Comments 0 Comment

So, for the first time in over two years, here is some new draft material from the Architect of Worlds project. First, some of the introductory text from the new section of the draft, then the first step in the next piece of the world design sequence.

The plan, for now, is to post these draft sections here, and post links to these blog entries from my Patreon page. None of this material will be presented as a charged update for my patrons yet. In fact, there may be no charged release in September, since this project is probably going to be the bulk of my creative work for the next few weeks. At most, I may post a new piece of short fiction as a free update sometime this month.

Designing Planetary Surface Conditions

Now that a planetary system has been laid out – the number of planets, their arrangement, their overall type, their number and arrangement of moons, all the items covered in Steps Nine through Fourteen – it’s possible to design the surface conditions for at least some of those many worlds.

In this section, we will determine the surface conditions for small “terrestroid” worlds. In the terms we’ve been using so far, this can be a Leftover Oligarch, a Terrestrial Planet, a Failed Core, or one of the major satellites of any of these. A world is a place where characters in a story might live, or at least a place where they can land, get out of their spacecraft, and explore.

Some of the surface conditions that we can determine in this section include:

Orbital period and rotational period, and the lengths of the local day, month, and year.
Presence and strength of the local magnetic field.
Presence, density, surface pressure, and composition of an atmosphere.
Distribution of solid and liquid surface, and the composition of any oceans.
Average surface temperature, with estimated daily and seasonal variations.
Presence and complexity of native life.

In this section, we will no longer discuss how to “cook the books” to prepare for the appearance of an Earthlike world. If you’ve been following those recommendations in the earlier sections, at least one world in your designed star system should have a chance to resemble Earth. However, we will continue to work through the extended example for Arcadia, focusing on the fourth and fifth planets in that star system.

Step Fifteen: Determine Orbital Period

The orbital period of any object is strictly determined by the total mass of the system and the radius of the object’s orbit. This is one of the earliest results in modern astronomy, dating back to Kepler’s third law of planetary motion (1619).

Procedure

For both major satellites and planets, the orbital period can be determined by evaluating a simple equation.

First Case: Satellites of Planets

To determine the orbital period of a planet’s satellite, evaluate the following:

$T\ =(2.77\ \times{10}^{-6})\ \times\sqrt{\frac{D^3}{M_P+M_S}}$

Here, T is the orbital period in hours, D is the radius of the satellite’s orbit in kilometers, and M_P and M_S are the masses of the planet and the satellite, in Earth-masses. If the satellite is a moonlet, assume its mass is negligible compared to its planet and use a value of zero for M_S.

Second Case: Planets

To determine the orbital period of a planet, evaluate the following:

$T\ =8770\ \times\sqrt{\frac{D^3}{M}}$

Here, T is the orbital period in hours, D is the radius of the planet’s orbit in AU, and M is the mass of the primary star in solar masses. Planets usually have negligible mass compared to their primary stars, at least at the degree of precision offered by this equation, and so don’t need to be included in the calculation.

Examples

The primary star in the Arcadia system has a mass of 0.82 solar masses, and the fourth and fifth planet orbit at 0.57 AU and 0.88 AU, respectively. The two planets’ orbital periods are about 4170 hours and 7990 hours. Converting to Earth-years by dividing by 8770, the two planets have orbital periods of 0.475 years and 0.911 years.

Alice has decided to generate more details for the one satellite of Arcadia V. This is a moonlet and so can be assumed to have negligible mass, while the planet itself has a mass of 0.65 Earth-masses. The moonlet’s orbital radius is about five times that of the planet, and Alice sets a value for this radius of 28400 kilometers. The moonlet’s orbital period is about 16.4 hours.

Architect of Worlds: The Next Chunk

August 24, 2020 Sharrukin Comments 1 comment

While I’m waiting for my consulting editor to have a look at The Curse of Steel, I’ve turned back to a project that I’ve been neglecting for too long: the world-building book Architect of Worlds. Several sections of that book already exist in a rough draft, which can be found at the Architect of Worlds link in the sidebar.

The bulk of the material I’ve already written is a design sequence, permitting the user to set up fictional star systems (or to fill in details for real-world systems). The idea is to let SF writers, game designers, tabletop game referees, and so on design locations for interstellar SF settings, using whatever combination of random chance and deliberate choice they prefer. The emphasis is on “hard SF” realism, as far as the state of exoplanetary astronomy will permit, and no dependencies on any specific tabletop rules system.

So far, the draft system permits one to place stars, planets, and moons, and get gross physical properties (mass, density, surface gravity) and dynamic parameters (orbital radius, eccentricity, and period) for each.

The next slice of the system will involve generating the surface conditions for such bodies, at least for the small “terrestroid” worlds that are likely to provide environments for SF adventure. At this point we’re talking about things like surface temperature (average and variations), atmospheric composition and pressure, the amount and state of water (or other volatiles) on the surface, what kind of native life might be prevalent, and so on.

I’ve been mulling this section over for a few years now, since the science involved is a lot more complicated and more difficult to reduce to a set of game-able abstractions.

When I designed a system like this for GURPS Space Fourth Edition, I made a deliberate design choice to reduce all the possibilities to a specific set of archetypes. That provided some backward compatibility with earlier versions of the GURPS system, and with the older Traveller systems that were an inspiration for both. For this book, though, I want to give the readers as much detail as I can, and let them decide what to use and what to set aside. That complicates the design.

So, a very rough overall outline of what’s going to be involved for a given “world” (that is, a terrestrial planet or moon with some likelihood of a solid surface):

The rotation rate of the world (including cases where the world is tide-locked or resonant with a primary). As a sidebar, this gives us quantities for the length of the natural day, month, and year.
The blackbody temperature and incidence of stellar wind for the world, based on the properties and distance of its primary star.
The strength of the world’s magnetic field, and the consequences for the size and strength of its magnetosphere (if any). If the world is a moon (for example, the satellite of a gas giant planet), then the primary’s magnetic field and magnetosphere may be relevant as well.
The world’s initial budget of volatiles – how much in the way of possible liquid or gaseous compounds was the world left with after its process of formation.
Atmospheric composition – what volatile compounds are likely to be gaseous at local temperatures, and can the planet hold onto them?
Atmospheric mass and pressure.
Hydrospheric composition – what volatile compounds are likely to be liquid or solid instead?
Hydrospheric mass and prevalence – how much of the world’s surface will be covered by what kinds of liquid or solid stuff?
Average surface temperature.
Estimated variations in surface temperature with the position on the surface, time of day, and so on.
Presence and complexity of native life – which may require a loop-back to adjust characteristics of the atmosphere, hydrosphere, and surface temperature.

All that’s the minimum for what the next section of the book needs to cover. There are a lot of dependencies back and forth here, which is one reason why I’ve struggled for so long to build this piece. I’m beginning to think I see how to design something workable, though. At least enough to get started. More over the next few weeks.

Editing the Novel

August 17, 2020 Sharrukin Comments 0 Comment

My plans regarding The Curse of Steel have evolved with remarkable speed over the past few days.

My novel-writing process seems to boil down to the following:

A long period of chaotic brainstorming, tinkering, and world-building work, in which the overall concept of the story can change many times. This stage can take several years and is likely to produce a lot of abortive partial drafts. Most of the novels I’ve worked on have never gotten past this point.
Eventually, the concept stabilizes in my head enough that I can produce the first complete draft of a novel. This has happened exactly three times in my entire career as a writer.
The first draft tells a complete story, but it probably has all kinds of plot holes, undeveloped characters, and vagueness of setting in it. After all, I was making it up as I went along – I seem to be much more a “pantser” than a “planner.” So now I go back and write a second complete draft, one that rounds out the story and patches most of those holes.

About eight years ago, my first mature original novel reached that second-draft stage. That was The Master’s Oath, a tale of time travel, alternate histories, and Hermetic magic that will absolutely never be seen again outside my dead files. It wasn’t until I was finished with that one that I had a “What in God’s name was I thinking” moment and realized the thing was utterly unpublishable. Decently written, not a bad adventure story, but bound to mortally offend big chunks of my audience. Lesson learned.

Now, as of last week, The Curse of Steel has reached the second draft stage. Lo, the creator looked upon his work, and he was pleased.

Now what?

Well, to be honest, my workflow doesn’t exist yet past this point. The Curse of Steel is the first original novel I’ve ever written that I honestly believe is publishable.

I spent a couple of weeks putting together a cover image for the book. While I worked on that, I thought about what the next steps should be. Should I just publish the second draft as is, and hope for the best?

The more I thought about that, the less comfortable I was with the idea.

I know my prose style is reasonably clean. When I was a freelance writer, more than one editor remarked on that. As an editor, I’ve seen enough prose from other people to be able to compare.

Meanwhile, I’ve had a few people reading my drafts, and they’ve been encouraging about the story.

On the other hand, a novel is a very different beast from a non-fiction book, there are necessary skills I may not have developed in full, and none of my early readers are experienced editors. I don’t have a decent writer’s circle to help me hammer my drafts into submission. What if I’m missing something?

No, scratch that, I know I’m missing something. Maybe two or three novels from now, I’ll have a better idea of what to do at this point. Right now I’m still not sure.

The obvious solution would be to hire an editor.

Of course, a skilled and reliable editor costs money. Not to mention, there are a lot of people out there ready to take advantage of would-be authors, offering cheap book-preparation services for top dollar without any guarantee of results. Ever since deciding to pursue self-publishing, I’ve been very cautious about laying out cash for such services.

On the gripping hand, I can afford to spend some money on the experiment.

So over the past week or so, I’ve done some research and developed two lines of attack.

One line is to search for software that can help a novelist pick nits in his prose style. Sure, everything has a spelling-and-grammar checker these days, but strong prose writing needs more than that. I need to be able to ferret out filler words, excess adverbs, phrases that I repeat too often, that kind of thing. I could do that by eye, but the process would be slow and painful, and I would be likely to miss the weaknesses in my own style.

Enter AutoCrit.

Autocrit is billed as a “self-editing platform,” and it certainly works as such. It’s essentially a web-based word processor, but it’s specifically designed to carry out a wide variety of specialized text searches and basic statistical analyses. It compares your text to a huge corpus from published novels, helping you find and carve out the flabby bits of your prose.

Using AutoCrit over the past three days, I’ve been able to rework The Curse of Steel with surprising speed and efficiency. Already I’ve cut a little over 2000 words of material, mostly filler words and repetitive phrases that didn’t add to the sense of each passage.

It’s been quite the eye-opener. Every writer needs something to rub his nose in the shortcomings of his prose style, or he isn’t likely to improve. Lacking an editor or a ruthless critique circle, something like this may be the next best thing.

AutoCrit isn’t ideal. It’s web-based, which I don’t care for. It chokes if you hand it more than 50,000 words of text at once, which means I have to edit my novel in chunks. It doesn’t handle special characters gracefully, so all my conlang words that have accents and umlauts in them get snarled up. Its import from Word, and its export back to Word, are both a little kludgy.

Still, I suspect I’ll have a third complete draft, with much tighter prose, by later this week.

The second line of attack is that I have, indeed, hired an editor. This involved a fair amount of searching through the Web, looking for editorial networks that are competent, reliable, and not outrageously expensive. The SFWA site was fairly helpful here – they don’t explicitly recommend editors, but they have an excellent checklist of things to consider in the process.

The editor I ended up with is being hired specifically to do a manuscript assessment, not a complete edit of the novel. This will set me back a few hundred dollars, and it may not end up being part of my usual workflow in the future. Still, the experiment should be worthwhile. I’m hoping he’ll be able to provide actionable feedback that I can use while producing a final complete draft – the last step in my development process before the book goes out the door.

At the moment, the plan looks like this:

Finish working through The Curse of Steel with AutoCrit (to be completed by about 21 or 22 August).
Wait for my editor to complete his review of the draft (probably about the end of September).
Produce the final release draft (to be completed by late October).
Publish the book!

So it looks as if The Curse of Steel will finally hit the virtual shelves by Halloween. There will be much rejoicing . . . and then I’ll get started on The Sunlit Lands, the second book in the series. One assumes that one won’t take nearly as long to reach fruition.

In other news, that four- or five-week gap in September, while I wait for my editor to finish his task? I think I may sit down and work on Architect of Worlds for a while. No promises . . . but I think my research, and the subconscious work in the back of my head, have reached the point where I may be able to develop a rough draft of the third chunk of the world design sequence. We’ll see how things go.

Star System Generation: A Neat Automated Tool

July 28, 2020 Sharrukin Comments 1 comment

Today I came across a neat example of automated star-system generation, based on the design sequence I wrote for GURPS Space, Fourth Edition back in the day.

It looks like a robust code base, supporting a web-based interface. You can generate star systems at random, possibly forcing a few parameters (existence of a garden world, position in an open cluster, and so on). You can pick from several naming schemes for the resulting planets.

The output includes a neat animated map of the system, and hierarchically tabulated information for randomly generated stars, planets, and moons. All in all, it looks very slick, and it seems to reflect the original game rules pretty accurately.

The source code for the project can be found at Jan Sandberg’s GitHub repository. The redditor Myrion_Phoenix hosts an instance of the application on his website as well.

I’ve mentioned my own more recent work on Architect of Worlds – it would be neat to see a similar automated version of that once it’s ready for release. In any case, this application looks very useful for folks who are running hard-SF games, whether using GURPS Space or something similar.