Human Destiny: Technology Levels

May 22, 2022 Sharrukin Comments 0 Comment

Here’s a small sample of material for the Human Destiny setting and game book that’s slowly taking shape. In the Cepheus Engine and related tabletop games, there’s often a system of “technology levels” that helps characterize what kind of gear and weapons one might expect to find on a given world. The concept has its problems, but it’s a quick shorthand that’s useful for game purposes. Since Human Destiny is eventually going to be published as a Cepheus Engine game, it seems useful to put together a set of “tech level” tables for the setting.

Here’s a first very rough draft for that section of the Human Destiny sourcebook.

Technology Levels in the Human Destiny Setting

The Khedai Hegemony maintains a sophisticated scheme for classifying the technological and social progress of emerging civilizations. The following system of “tech levels” is a (vastly simplified) shorthand for the Hegemony’s scheme.

General Technology

As is the standard in any Cepheus Engine game, Technology Level or Tech Level is a measure of the social, scientific, and industrial progress of a given world or society. In Hegemony documents, each TL has an evocative descriptor, and can be associated with an approximate era in human history.

TL	Descriptor	Approximate Date or Typical World
0	Era of Stone Tools	Paleolithic, Mesolithic, or Neolithic society
1	Era of Metal Tools	3000 BCE
2	Era of Exploration	1500 CE
3	Era of Mechanization	1750 CE
4	Era of Electricity	1900 CE
5	Era of Radio	1930 CE
6	Era of Atomic Power	1950 CE
7	Era of Space Exploration	1970 CE
8	Era of Information	1990 CE
9	Era of Crisis	2020 CE
10 (A)	Low Interstellar Society	Minor human colony world or outpost
11 (B)	Low Interstellar Society	Major human colony world or outpost
12 (C)	Average Interstellar Society	Maximum level for the Human Protectorate
13 (D)	Average Interstellar Society	Maximum level for a second-tier client society
14 (E)	High Interstellar Society	Maximum level for a first-tier client society
15 (F)	High Interstellar Society	Maximum level for the Khedai Hegemony as a whole

It may not be immediately obvious, but the Hegemony’s scheme for classifying technological progress includes two singularities, each of which creates a discontinuity in the above table.

The normal pattern for any newly evolving technological civilization is to progress from TL 0, passing through the higher levels in order, finally reaching some maximum level of social and technological progress. At this point the civilization invariably suffers an existential crisis that, at a minimum, forces all its component societies back to some lower TL. This may happen multiple times before the sapient species in question is finally driven into extinction. The highest point of independent development is almost never higher than TL 9. In fact, civilizations that reach TL 9 on their own almost always suffer particularly deadly collapses, likely to cause immediate species extinction – hence the term “Era of Crisis.”

The transition from TL 9 to TL A represents the first discontinuity or singularity in the scheme. Very few civilizations manage to pass the Era of Crisis on their own. Almost all societies that survive the transition and attain interstellar status do so only because an older civilization intervenes, as the Khedai Hegemony did with humanity.

Under the Praxis observed by the Khedai Hegemony, newly discovered sapient societies at TL 0-3 are observed from a distance under a strict non-interference policy. Societies at TL 4-9 are subject to close observation, and possibly annexation if (as in almost all cases) they appear unlikely to survive on their own.

The interstellar levels that follow (TL A through TL F) do not represent a hierarchy of new technologies that appear one after the other in a progressive fashion. Instead, they represent an array of mature technologies, all millions of years old, which are all available throughout the Hegemony. The TL of a world which falls in this range represents the kind of technology that is widely available on that world, because it is locally manufactured and can be supported by existing infrastructure. Items from a higher TL will also be available, but possibly at a higher cost in social credit, or with specific limitations under the Praxis.

Humans know nothing about any technologies above TL F. Humans may speculate, and the khedai doubtless know what technologies might be possible, but under the Praxis such possibilities are cloaked in silence. A few humans suspect that this silence conceals a second discontinuity or singularity, beyond which even the Hegemony dares not go.

Energy Technologies

The Hegemony’s scheme for classifying technologies is most strongly determined by a society’s ability to harness and direct energy to carry out the work of civilization.

TL	Typical Developments
0	Muscle power Domesticated animals Slave labor
1	Hydromechanical power Water wheels
2	Wind power Windmills
3	Steam power Exploitation of fossil fuels (coal) Crude electrical transmission and storage
4	Widespread use of electrical power Exploitation of fossil fuels (oil, natural gas) Oil refining to produce high-quality fuels Hydroelectric power
5	Rural electrification Urban power grids
6	Nuclear fission reactors Regional power grids
7	Increasing use of solar power Continental power grids
8	Mass application of renewable energy
9	Crude “smart grids” Possible abandonment of fossil fuels
10 (A)	Advanced “smart grids” Advanced fission power Superconducting power transmission Hyper-efficient power cells Solar power satellites Complete abandonment of fossil fuels
11 (B)	Nuclear fusion reactors
12 (C)	Advanced fusion power
13 (D)	Antimatter generation and transport
14 (E)	Advanced antimatter power Portable fusion power Catalyzed fusion
15 (F)	Miniaturized fusion power

Communications and Information

This category covers technologies for generating, transmitting, storing, and applying information. It also includes various forms of artificial intelligence and artificial sapience.

TL	Typical Developments
0	Oral communication
1	Written communication Printing press (block printing) Crude cryptography
2	Printing press (movable type) Advanced cryptography (manual)
3	Telegraph Early telephones
4	Teletype Widespread telephone networks Advanced cryptography (electromechanical)
5	Radio broadcasting Massive special-purpose computing devices
6	Television broadcasting Massive general-purpose computing devices Information theory
7	Early packet-switched networks Personal computers Industrial automation Advanced cryptography (digital) Public-key cryptography
8	Global Internet Advanced personal computers Advanced ICS/SCADA systems Large-scale public-key infrastructures
9	Miniaturized personal computers Early natural-language interfaces Early automatic translation Sophisticated robots and drones “Cloud” computing Crude quantum computation
10 (A)	Advanced natural-language interfaces Advanced automatic translation Cybershells Ubiquitous computing Large-scale quantum computation
11 (B)	Sophisticated personal assistants Advanced expert systems Advanced cybershells Sophisticated personality emulation
12 (C)	Early Virtual Sapience systems Fully Turing-capable systems Undirected machine learning “City minds”
13 (D)	Advanced Virtual Sapience systems
14 (E)	Early Artificial Sapience systems Proof-of-consciousness systems “World minds”
15 (F)	Advanced Artificial Sapience systems Transapience threshold

Environmental

This category covers technologies that can alter or maintain planetary environments. It also covers common developments in environmental awareness – the process by which a civilization learns how its own activities can impact the environment upon which it relies for support.

TL	Typical Developments
0	Agriculture and pastoralism Early trade networks Forest clearing Overhunting Megafaunal extinction
1	Early cities Basic aqueducts and sanitation Advanced trade networks Continental empires
2	Global trade networks Transcontinental empires and colonization
3	Indoor plumbing Advanced sanitation Large-scale use of fossil fuels Large-scale habitat destruction begins
4	Super-cities (>1 million) Large-scale water treatment Sophontogenic climate change begins
5	Super-cities (>10 million)
6	Megalopolitan regions (>50 million) “Green Revolution” in agriculture Awareness of global harms from pollution
7	Megalopolitan regions (>100 million) Sophontogenic mass extinction begins Awareness of sophontogenic climate change
8	Gene-modified crop species Awareness of sophontogenic mass extinction
9	Crude geoengineering Civilizational collapse
10 (A)	Organic urban reserves Advanced geoengineering Climate and ecological remediation De-extinction
11 (B)	Domed cities Artificial species to fill ecological niches Type I (Mars) terraforming
12 (C)	Advanced climate and ecological remediation “Biome minds” monitor wild ecosystems
13 (D)	Type II (Venus, Mercury, Luna) terraforming
14 (E)	“World minds” monitor global ecosystems
15 (F)	Type III (extremal) terraforming

Medical

This category covers medical and biological technologies.

TL	Typical Developments
0	Herbal remedies Crude surgery and prosthetics
1	Diagnostic process Basic understanding of anatomy
2	Advanced understanding of anatomy Crude immunization techniques
3	Germ theory and bacteriology Epidemiology Antiseptic surgery Advanced anesthesia Crude psychiatry
4	Antibiotics X-rays and other internal imaging Public health measures Mass vaccination
5	Blood transfusions Discovery of transplant rejection
6	Eradication of some infectious diseases Discovery of the structure of DNA
7	Theories of molecular evolution Crude genetic engineering Advanced prosthetics
8	Crude gene therapies Simple genetically modified organisms Crude sense-replacement implants
9	Advanced sense-replacement implants Crude artificial organs
10 (A)	Advanced therapeutic gene modification Extensively engineered organisms Full-function artificial organs Advanced geriatrics Effective psychiatry
11 (B)	Artificial plant and animal species Simple pantropic engineering
12 (C)	Nanotech therapies Brain transplants Personality recording (cyber ghosts) Advanced pantropic engineering (germ-line)
13 (D)	Full-body prosthetics (“bioroid” bodies)
14 (E)	Biological immortality Full personality uploading (cyber immortality)
15 (F)	Cyber transcendence

Surface Transport

This category covers technologies for transport on or near a planetary surface.

TL	Typical Developments
0	Long-distance travel by foot Domestic animals (riding, beasts of burden)
1	Crude wheeled vehicles Rowed watercraft Early sailed watercraft
2	Advanced wheeled vehicles Blue-water sailing ships
3	Steam engines Railroads Steamships
4	Internal combustion engines Early automobiles Early aircraft
5	Widespread automobiles Local highway systems Jet aircraft Containerized shipping
6	Large nuclear-powered vehicles Continental highway systems Supersonic aircraft Global standards in containerization
7	Early maglev systems
8	High-speed maglev systems
9	Early “self-driving” vehicles
10 (A)	Early gravitic transport Advanced “self-driving” vehicles Regional and continental hyperloop
11 (B)	Advanced gravitic transport Transcontinental hyperloop
12 (C)	Beanstalk interface
13 (D)
14 (E)
15 (F)

Space Transport

This category covers technologies for transport and artificial stations in interplanetary or interstellar space.

TL	Typical Developments
0
1
2
3
4
5	Sounding rockets
6	Orbital rockets Early interplanetary probes
7	Manned spacecraft Advanced interplanetary probes
8	Reusable shuttles Large-scale interface transport Space telescopes Small orbital stations (constant resupply)
9	Crude interstellar probes Manned interplanetary outposts Moderate orbital stations (constant resupply)
10 (A)	Early gravitic (reactionless) drives Artificial gravity Interplanetary colonization Large and self-sufficient orbital stations Planetoid habitats
11 (B)	Advanced gravitic drives “Space cities”
12 (C)	Slow FTL (Alcubierre) drives Interstellar colonization
13 (D)	Medium FTL drives Planetary “ring cities”
14 (E)	Fast FTL drives
15 (F)	Starbridge (wormhole) construction

Heavy Weaponry

This category covers weapon technologies for large-scale military use, as well as military applications of some other technological categories.

TL	Typical Developments
0
1	Battering ram Torsion-powered war engines War chariot War galley
2	Bombards Bronze and iron cannon Crude rocket artillery Blue-water warships
3	Artillery Rocket artillery Heavy machine guns Steam-powered warships Reconnaissance balloons
4	Crude chemical and biological weapons Crude military aircraft
5	Atomic weapons Long-range ballistic missiles Advanced chemical and biological weapons Advanced military aircraft
6	Thermonuclear weapons Transcontinental-range ballistic missiles Nuclear-powered warships
7
8	Early applications of cyberwarfare
9	Full integration of cyber into kinetic warfare Extensive use of drones and unmanned vehicles Heavy mass-driver weapons and railguns
10 (A)	Advanced cyberwarfare Nanotech weapons (“devourer clouds”) Advanced mass-driver weapons and railguns Heavy laser cannon
11 (B)	Gravitic artillery Plasma cannon Neural suppression field (“stunner”) weapons
12 (C)	Fine-scale remote stunners Nuclear fission suppression systems
13 (D)	Fusion-temperature plasma cannon X-ray laser cannon
14 (E)
15 (F)	Gamma-ray laser cannon

Personal Weaponry

This category covers weapon technologies for individual use.

TL	Typical Developments
0	Clubs and cudgels Stone-tipped spears Bow and arrow Hide and leather armor
1	Bronze and iron swords Metal spearheads and arrowheads Longbow, composite bow, and crossbow Bronze and iron armor Ring and scale mail
2	Matchlock and wheellock firearms
3	Flintlock firearms Rifled firearms Repeating firearms
4	Cartridge ammunition Light machine guns
5	Advanced rifled firearms
6	Submachine guns
7	Grenade launchers Advanced body armor (ballistic fabrics)
8	Crude “smart weapons”
9	Crude mass-driver or “gauss” weapons
10 (A)	Advanced gauss weapons
11 (B)	Gravitic weapons Personal laser weapons
12 (C)	Personal plasma weapons Personal stunner weapons
13 (D)
14 (E)	Personal fusion weapons Personal X-ray laser weapons
15 (F)

Hard Left Turn at Bakhuysen Crater

May 15, 2022 Sharrukin Comments 0 Comment

As sometimes happens, my plan for creative work for the current month has taken a big leap out into left field. My original plan for May was to write up the last open section of Architect of Worlds, and release that for my patrons. Instead, I think I’m going to be living on Mars this month.

One of my Human Destiny subprojects is to develop the future history of colonization and terraforming of Mars in that universe. In a sense, Mars is where human beings first figure out how they might fit into the Hegemony’s interstellar society – setting aside the follies of old Earth, disciplining themselves to a centuries-long project in a harsh environment, learning galactic technologies and ways of life. I’ve already written one piece of fiction set on the planet, and Mars is going to be important for the story of my lead character, Aminata Ndoye. Meanwhile, I anticipate dedicating a lengthy section of the Atlas of the Human Protectorate just to describe late-23rd-Century Mars.

The spark for getting back to this subproject was the computer game Per Aspera. This is a logistics-engine game, focused on the colonization and terraforming of Mars. Early in May, the developers of Per Aspera released a new DLC which added a bunch of useful features to the game’s model. I sat down to spend a little time experimenting with the new version, thinking I would just spend an evening or two on it . . . but the result was a superb run which gave me all kinds of setting and story ideas. Forget devoting a section of the Atlas to Mars, I suspect I could write a complete tabletop RPG dedicated to this one planet.

Okay, that’s probably an excessive notion. Still, right now I think I could easily write a first draft of that section of the Atlas. I’m also experimenting with the QGIS software package as a tool for making useful maps of Mars. We have a lot of data about the topographical layout of the planet, so producing plausible maps is not going to be a problem.

So that’s the new plan for May: at the very least, produce a new interim partial draft of the Atlas for my patrons and readers. That will be a charged release if there’s at least ten or twelve thousand words of new material. If time permits, maybe knock out one or two maps of terraformed Mars to go with the new text. If I can get Mars out of my system over the new couple of weeks, then I should be able to turn back to that last section of Architect in June.

Status Report (16 April 2022)

April 17, 2022 Sharrukin Comments 2 comments

I’ve had some ups and downs so far this month, but at about the midpoint I do seem to be on track to reach some good milestones.

I spent the first week or so of April doing an overhaul of parts of the Architect of Worlds design sequence. I started out just trying to add an alternative mechanism for producing gas giant planets, but that ended up carrying so many implications that I eventually had to overhaul most of Steps Nine through Eleven. I’m still not happy with the smoothness of the revised text, although the model seems to be working well enough.

Once that was done, I went back to an extended test run for Architect, generating planetary systems for a reasonable cut of the stellar population near Sol. I’m working with the data set associated with the paper The 10 parsec sample in the Gaia era – this is probably the best census of the solar neighborhood available at the moment. As of this evening, I’ve gotten about to the five-parsec radius.

I started out systematically generating planetary systems for every star on the list. Mostly this was to verify something I suspected about red-dwarf and brown-dwarf systems – that they are very unlikely to generate planets where humans can comfortably settle. So far I think I’ve confirmed that suspicion. I don’t think it’s impossible to find an Earthlike world in a red-dwarf system, but those stars have so many factors stacked against them that such cases are probably quite rare. Scientific and mining outposts, maybe, but not prosperous colonies. So after I generated 19 red-dwarf and brown-dwarf systems, I dropped those and concentrated on the brighter stars, spectral type K and up.

I now have 13 planetary systems for those brighter stars, and I’m encouraged to see that Architect is doing a decent job of generating Earthlike worlds (generously defined) for them. If we want air with sufficient free oxygen in it to breathe without too much artificial aid, that doesn’t seem to be a problem.

Counting Earth, I have six habitable worlds within five parsecs of Sol:

Sol III (Earth)
Alpha Centauri A-III (a super-Earth with a helium-nitrogen-oxygen atmosphere)
61 Cygni B-III (tide-locked)
Epsilon Indi A-II (tide-locked)
Groombridge 1618 III (tide-locked)
70 Ophiuchi A-III (a true Earth-analog, no helium, not tide-locked)

Not bad. Looks like Architect is going to give us a fair number of tide-locked Earthlikes, and the occasional super-Earth with weird but breathable atmosphere. The variety even in this short list is nice to see.

Eventually I plan to work all the way out to the ten-parsec radius, but this will do for now as a stress test for Architect. For the bottom half of April I’m going to switch to writing up some of these worlds and planetary systems, as a first installment in the rough draft of the Atlas of the Human Protectorate.

So for my patrons and readers, here’s the likely release schedule for this month.

I do have a new interim draft (v0.9) of the main section of Architect of Worlds, but I think I’m going to hold off on pushing that out to everyone until I’ve had a chance to go through and polish up the text a bit. I think I also want to get to the long-delayed project of cleaning up all the mathematical formulae so that I’m using more standardized variable names and formats. You may see a v0.9 draft next month sometime.

On the other hand, I’m pretty confident I can have a first interim draft of the Atlas of the Human Protectorate ready by the end of April, with at least 10,000 to 12,000 words of material in it. That v0.1 draft will be a charged release for my patrons. I may charge for further additions to that draft, as I have with new sections of Architect or other book-length projects, but only if and when there’s enough genuinely new material to justify it.

More updates as things develop, as always.

New Models for Gas Giant Formation

April 6, 2022 Sharrukin Comments 1 comment

Protoplanetary disk of the young star AB Aurigae. Notice the distinctive spiral-arm-like structures. One of these appears to be associated with the formation of a massive gas giant planet, at an unusually large distance from the protostar.

I’ve spent the first few days of April working with the current version of Architect of Worlds, building planetary systems for nearby stars. Almost immediately, I’ve run into an issue which may be connected to recent scientific results.

It’s ironic that the process of writing Architect has been a little like doing original scientific research. The book’s main design sequence, when you get right down to it, is a big elaborate model that I hope will have predictive value, in that it will generate planetary systems that resemble what we’re seeing in the real universe. The goal is fictional plausibility, not true explanatory power, but the process of development is often the same. If I start comparing the model to the real universe (that is, to known exoplanetary systems) and the model seems unable to mimic the visible results, then there’s a problem and I need to adjust the model.

The immediate issue is that the current (v0.8) draft of the Architect design sequence assumes the core accretion model for planetary formation. That is to say, we assume that planets form in certain regions of the protoplanetary disk, when solid particles clump together and form protoplanets massive enough to start quickly accreting more material. We expect smaller rocky planets to form inside the “snow line,” in a region where water ice isn’t available. We expect gas giant planets to form outside, with the largest gas giant preferentially forming close to the line. We also play with planetary migration and the so-called “Grand Tack” model, so that the largest gas giant may move inward or outward from that initial position, but only within reasonable limits.

Our own planetary system seems to fit that model reasonably well, as do many of the other exoplanetary systems we’re aware of. There’s a catch, though. In some cases, we find what appears to be the largest gas giant forming far outside the snow line. Much further than the core-accretion model can account for, even with a generous “Grand Tack” hypothesis thrown in. Here are some examples I’ve pulled together over the past few days:

Star	Predicted Snow Line	Innermost Gas Giant	Ratio
Wolf 359	0.15 AU	1.85 AU	12.3
Proxima Centauri	0.17 AU	1.49 AU	8.8
Lalande 21185	0.56 AU	2.85 AU	5.1
Groombridge 34	0.59 AU	5.40 AU	9.2
Gliese 832	0.75 AU	3.46 AU	4.6
Epsilon Indi	1.75 AU	11.55 AU	6.6
HR 8799	8.10 AU	16.25 AU	2.0
AB Aurigae	23.30 AU	93.00 AU	4.0

Of all these cases, only HR 8799 is one that the current version of Architect could easily handle, and even that planetary system is problematic – because we know of four exoplanets there, and the one on this table is only the innermost of the four. Most of these gas giants are much further out than my current “Grand Tack” procedures could possibly account for.

Meanwhile, the masses of most of these exoplanets are a lot higher than we would normally expect for their primary stars. For example, several of these stars are low-mass red dwarfs – we wouldn’t normally expect them to generate gas giant planets at all. Some of the others have planets several times as massive as Jupiter, approaching masses more typical of brown dwarfs.

Notice the first few rows on this table are several of the stars closest to Sol. If I’m running into difficulty this quickly, that means I’m not seeing rare special cases here. There’s some way in which planetary formation just isn’t (always) working as I expect. Not the first time this has happened during the development of Architect of Worlds, and it won’t be the last.

Fortunately, there’s a new model that seems to help. That’s the so-called disk instability model for the formation of gas giant planets. Apparently, at least in some cases, gas giants don’t form close to the snow line via a well-behaved process of core accretion. Instead, especially if the protoplanetary disk is unusually dense, or if gravitational interaction from nearby stars stirs things up, the disk becomes unstable. Simulations of the process show that much of the disk can form “spiral arms” rather like those of a galaxy . . . and the result can be the rapid formation of unusually massive planets much further out from the protostar than expected.

We’ve actually imaged an example of this happening, as some very recent results show. The very young star AB Aurigae appears to be in the process of forming a massive gas giant, over 90 AU out from the protostar (the last line of the table above covers this case). This, along with some other observations, seems to lend some credence to the disk instability model for at least some planetary formation.

What this means for Architect of Worlds is that I’m probably going to need to add some material to the current Steps Nine and Ten, in which the structure of the protoplanetary disk and the arrangement of the outer planetary system are determined. I think I’ve already worked out some of the details, so I may be able to make the necessary revisions to my working (v0.9) draft within another day or two. Then I should be able to get back to the test run on which I had planned to spend the month of April.

All of which means that my patrons and other readers can reasonably expect a free v0.9 update to the main Architect document this month, along with anything else I produce.

Architect of Worlds: the “Special Cases” Outline

March 6, 2022 Sharrukin Comments 4 comments

A quick taste for what I’ll be working on this month. This is a section of the eventual book that will cover “special cases” in the design process, things that stand as exceptions or as extra details outside the main body of the world design sequence.

Hopefully this will end up being enough material (10-15 thousand words or more) to justify a new release for my patrons this month. Actually, now would also be a good time for any of my readers to suggest anything else that might fit into this section. Drop me a line if there’s some special topic that you want to see addressed that isn’t in this sketch outline.

Special Cases in Worldbuilding

Generating Stars in Unusual Regions
- OB Associations
- Open Clusters and Stellar Associations
- Inter-Arm Space
- Galactic Halo
Unusual Stars
- Massive Main-Sequence Stars
- Neutron Stars
- Black Holes
- Flare Stars
Planetary Systems for Non-Main Sequence Stars
- Brown Dwarfs
- Subgiant and Giant Stars
- White Dwarfs and Stellar Remnants
Planetary Systems for Multiple Stars
Special Features for Planetary Systems
- Asteroids and Comets
- Planetoid Belts
- Kuiper Belt
- Oort Cloud
- Rogue Planets
- Trojan Planets
Unusual Worlds
- Ammonia Worlds
- Carbon Worlds
- Chthonian Worlds
- Lava Worlds
Fine-Tuning World Climate
- Effects of Orbital Eccentricity
- Effects of Obliquity
- Effects of Daily Rotation
- Effects of Altitude
- Effects of Local Geography
- Tide-Locked Worlds

Two Planetary Systems

February 18, 2022 Sharrukin Comments 0 Comment

Time for a quick taste of how the new Architect of Worlds version is turning out.

Long-time followers of this project will remember the two running examples in the draft: planetary systems named Arcadia and Beta Nine that are intended to demonstrate how the system works in practice. I’m in the process of re-working all of the examples, which should be the last step before I share the current draft with my patrons and my readers here.

Here are a couple of tables to suggest some of the results of the revised system.

Arcadia Planetary System
Orbital Radius	Planet Type	Planet Mass	Density	Radius	Surface Gravity
0.254 AU	Terrestrial Planet	0.26	0.75	4470 km	0.53 g
0.380 AU	Terrestrial Planet	1.75	1.09	7460 km	1.28 g
0.580 AU	Terrestrial Planet	1.34	1.10	6800 km	1.17 g
1.00 AU	Terrestrial Planet	0.22	0.74	4250 km	0.49 g
2.12 AU	Planetoid Belt	N/A	N/A	N/A	N/A
4.08 AU	Large Gas Giant	460	0.20	84100 km	2.64 g
8.12 AU	Medium Gas Giant	180	0.075	85300 km	1.00 g
12.0 AU	Small Gas Giant	52.0	0.14	45800 km	1.00 g
17.6 AU	Failed Core	2.80	1.13	8620 km	1.53 g

Not too many surprises here – this resembles the previous version’s Arcadia system fairly strongly. For some context, the primary star here is a singleton K2V, with about four-fifths the mass and one-third the luminosity of Sol. The third planet (at 0.58 AU) is the Earthlike candidate that I intend to use as an example for the last portion of the design sequence.

Beta Nine Planetary System
Orbital Radius	Planet Type	Planet Mass	Density	Radius	Surface Gravity
0.027 AU	Terrestrial Planet	1.22	1.09	6610 km	1.13 g
0.038 AU	Terrestrial Planet	0.94	1.01	6220 km	0.99 g
0.062 AU	Planetoid Belt	N/A	N/A	N/A	N/A
0.135 AU	Small Gas Giant	12.0	0.29	22000 km	1.00 g
0.390 AU	Failed Core	2.80	1.16	8540 km	1.56 g

The Beta Nine primary is an M4V red dwarf, with about 0.18 solar masses and less than 1% of Sol’s luminosity. It also has a brown-dwarf companion that cuts off planetary formation too far away from the primary. This planetary system is actually quite a bit different from the previous draft’s Beta Nine. The new model I’m using provides enough planetesimal mass for at least a small gas giant world, and it also allows for the possibility that some of that planetesimal mass “migrates” into the inner system to help form rocky worlds. So we end up with more planets this time, and the terrestrial worlds are considerably bigger.

One inspiration here is the TRAPPIST-1 planetary system. My old model didn’t have much trouble generating a planetary system like that for a small red dwarf, but it needed a pretty massive protoplanetary disk to do it. Under the new model, a red dwarf star doesn’t need an improbably big disk mass to have a chance at Earth-sized worlds. Given how many red dwarfs we’ve found with planets of significant size, I suspect the new model fits the facts better.

I’m hoping to have the new draft out as a free update for my patrons, and as an update to the version posted on this site, within a few days.

New Models for Planetary Formation

January 24, 2022 Sharrukin Comments 5 comments

Rings in the protoplanetary disk around the young star HD163296 (Image courtesy of Andrea Isella/Rice University)

The science of planetary formation has been advancing in leaps and bounds for the last decade or two, driven by the discovery of thousands of exoplanets and fine-detail imaging of other planetary systems. This has been giving us a lot of insight into not only the history of our own Solar System, but also the general case of planetary formation elsewhere.

With my Architect of Worlds project, I’ve been trying to keep abreast of the current science while designing a world-building system for use in game design and literary work. The current state of the system is pretty good, I think, but it’s a bit complicated. I’ve built a model that tracks the formation of a system’s primary gas giant (if any), follows that planet as it migrates inward (and possibly outward), and uses the results of that evolution to determine the mass and placement of the rest of the planets. Lots of moving parts there, and a few of the steps are kind of unwieldy.

Now there’s some recent research suggesting that I might be able to simplify the model and still get good results. The pertinent paper is “Planetesimal rings as the cause of the Solar System’s planetary architecture,” by Andre Izidoro et al., released in December 2021. Here’s a layman’s article from Rice University: “Earth isn’t ‘super’ because the sun had rings before planets,” published on 4 January.

The idea is that it wasn’t specifically the migrations of Jupiter that brought about the architecture we see of the inner Solar System. Instead, the protoplanetary disk probably had several “pressure bumps,” places where infalling particles released gases due to the increasing temperature close to the embryonic Sun. These pressure bumps tended to accumulate dust particles, and created an environment where planetesimals could form and coalesce, without continuing to spiral into the Sun. The authors of the paper predict the presence of three such “pressure bumps,” which ended up giving rise to the rocky inner planets, the gas giants, and the Kuiper Belt objects respectively.

The idea makes a lot of sense, especially since we’ve started to get fine-detail images of young stars and their protoplanetary disks, and we sometimes see exactly the system of “rings” that the model would predict. Take the image that leads the Rice University article, which I’ve included above.

Scientifically, speaking, the neat thing about this new model is that it explains several things that previous models (which assumed a more uniform disk and relied on Jupiter-migrations to make things work out) had trouble with – especially the specific isotopic composition of inner-system as opposed to outer-system material. The new model also doesn’t have any trouble producing a small Mercury or Mars, or a planetoid belt (with mixed composition) between Mars and Jupiter.

From my perspective, it may mean that I can simplify the model on which Architect of Worlds is built, making the whole thing much easier for people to use. I’m going to be reading the literature on this, and thinking about the implications.

Photosynthesis on Red Dwarf Planets

September 8, 2021 Sharrukin Comments 0 Comment

Artist’s conception of a landscape on a planet in the nearby Gliese 667 star system (ESO/L. Calçada)

Here’s another interesting result that has a strong bearing on the Architect of Worlds project:

Super-Earths, M Dwarfs, and Photosynthetic Organisms: Habitability in the Lab

We’ve assumed for a while that the planets of red dwarf stars are poor candidates for habitability, for a couple of reasons.

The main problem is that any planet close enough to a small, cool red dwarf star to bear liquid water is going to find itself seriously sandblasted during the star’s energetic “flare star” era. Without a strong magnetic field – itself unlikely if the planet rotates slowly because it’s tide-locked – it’s going to have a hard time retaining any atmosphere. If there’s plenty of geological and volcanic activity, an atmosphere may reconstruct itself once the primary star settles down.

The more subtle problem is that red dwarf starlight is lacking in the shorter visible-light frequencies driving the kind of photosynthesis we’re familiar with. A red dwarf may produce most of its energy output in the near infrared, which doesn’t do much for green plants. If photosynthesis has a hard time taking off, you’re not likely to get a breathable atmosphere with plenty of free oxygen in it.

The current draft of Architect of Worlds addresses both of these factors, in such a way that it’s actually quite difficult to generate an Earthlike world circling any but the most massive red dwarf stars (maybe M0 V or M1 V, at most).

The paper linked above, though, seems to indicate that this is too conservative. The authors worked with certain kinds of extremophile photosynthetic bacteria found on Earth. They subjected them to simulated red dwarf sunlight . . . and found that the bacteria carried on photosynthesis quite well. Even some of the more common bacteria they tested were able to carry on some photosynthetic activity under simulated red dwarf starlight.

This may be one of those cases where we need to account for the possibility of “life not quite as we know it” being able to exploit a niche we wouldn’t expect. Assuming a planet can retain (or rebuild) its atmosphere after the primary’s flare-star era, photosynthesis that leaves it with plenty of free oxygen in the air may not be as unlikely as we thought. I think one thing I’m going to do this month is to adjust parts of the Architect of Worlds design sequence to allow for this possibility.

Two Starships

June 12, 2021 Sharrukin Comments 1 comment

I’ve been playing with the current (Mongoose Publishing) edition of Traveller, specifically their version of the High Guard starship design rules. Here are a couple of ship designs that might possibly be relevant to another project I’m working on. Also, hopefully, of interest to Traveller fans . . .

Niarchos-class Far Trader (Modified)

These small merchant vessels are based on the TL12 Niarchos-class far trader, but have been specifically modified to support covert operations. They may (appear to) make a profit through normal free-trade operations, but are also likely to be covertly subsidized by an interstellar state.

Tech Level: 12
Hull: 200 tons, streamlined (80 Hull points, MCr12)
Armor: Crystaliron, 2 points (5 tons, MCr1.2)
M-Drive: Thrust 2 (4 tons, MCr8)
J-Drive: Jump 2 (15 tons, MCr22.5)
Power Plant: TL12 Fusion, Power 105 (7 tons, MCr7)
Fuel Tanks: Jump 2, 4 weeks operation (41 tons)
Bridge: Standard (10 tons, MCr1)
Computer: Computer/20 (MCr5)
Sensors: Improved (Power 4, 3 tons, MCr4.3)
Weapons: Double turret with pop-up mounting, Pulse Laser x2 (Power 9, 2 tons, MCr3.5)
Systems:
- Fuel Scoop
- Fuel Processor – 40 tons/day (Power 2, 2 tons, MCr0.1)
- Cargo Crane (3 tons, MCr3)
- Advanced Probe Drones – 5 TL12 drones (1 ton, MCr0.8)
- Library (4 tons, MCr4)
Staterooms:
- High Staterooms x1 (6 tons, MCr0.8)
- Standard Staterooms x8 (32 tons, MCr4)
- Low Berths x6 (Power 1, 3 tons, MCr0.3)
Software:
- Electronic Warfare/1 (Bandwidth 10, MCr15)
- Maneuver/0 (Bandwidth 0)
- Jump Control/2 (Bandwidth 10, MCr0.2)
- Library (Bandwidth 0)
Common Areas: 10 tons (MCr1)
Cargo: 52 tons
Standard Crew: Pilot, Astrogator, Engineer, Gunner, Medic, Steward. Usual crew roster combines Pilot and Astrogator, Engineer and Gunner, and Medic and Steward.
Cost: MCr93.7, monthly maintenance cost Cr7810.

Chen Zuyi-class Corsair

These ships were designed for long-term operation and small-scale commerce raiding in hostile space. Most of them have been sold to pirates, mercenaries, planetary governments seeking to maintain their independence, and other “troublemakers.”

Tech Level: 11
Hull: 400 tons, streamlined (160 Hull points, MCr24)
Armor: Crystaliron, 4 points (20 tons, MCr4.8)
M-Drive: Thrust 3 (12 tons, MCr24)
J-Drive: Jump 2 (25 tons, MCr37.5)
Power Plant: TL8 Fusion, Power 250 (25 tons, MCr12.5)
Fuel Tanks: Jump 2, 4 weeks operation (83 tons)
Bridge: Standard (20 tons, MCr2)
Computer: Computer/15 (MCr2)
Sensors: Military Grade (Power 2, 2 tons, MCr4.1)
Weapons:
- Triple turret, Pulse Laser x3 (Power 13, 1 ton, MCr4)
- Triple turret, Pulse Laser x3 (Power 13, 1 ton, MCr4)
- Triple turret, Missile Rack x3 (Power 1, 1 ton, MCr3.25)
Systems:
- Fuel Scoop
- Fuel Processor – 80 tons/day (Power 4, 4 tons, MCr0.2)
- Cargo Crane (3 tons, MCr3)
- Breaching Tube (3 tons, MCr3)
- Forced Linkage Apparatus (2 tons, MCr0.075)
- Armory x2 (2 tons, MCr0.5)
- Medical Bay (4 tons, MCr2)
- Training Facilities x12 (Power 24, 24 tons, MCr4.8)
- Workshop x2 (12 tons, MCr1.8)
Staterooms:
- High Staterooms x1 (6 tons, MCr0.8)
- Standard Staterooms x4 (16 tons, MCr2, set up for double occupancy)
- Barracks x12 (24 tons, MCr1.2)
- Brig x1 (4 tons, MCr0.25)
- Low Berths x6 (Power 1, 3 tons, MCr0.3)
Software:
- Fire Control/1 (Bandwidth 5, MCr2)
- Maneuver/0 (Bandwidth 0)
- Jump Control/2 (Bandwidth 10, MCr0.2)
- Library (Bandwidth 0)
Common Areas: 13 tons (MCr1.3)
Cargo: 90 tons
Standard Crew: Pilot, Astrogator, 2 Engineers, 3 Gunners, Medic, 12 Marines.
Cost: MCr145.575, monthly maintenance cost Cr12200.

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