I’ve posted a new short story, “Encounter in the Dawn,” to the Free Articles and Fiction section of this blog.
“Encounter in the Dawn” is an excerpt from a piece of fan-fiction I wrote back in the 2012-2014 timeframe. It’s completely separate from the fan-fiction’s source material, however, and works as an original stand-alone vignette. Consider it an experiment in writing well-researched historical fiction, without any speculative elements at all.
I’ve been blocked on my major literary project in the fantasy genre for over a year now. I did manage to write one piece of short fiction in the Krava’s Legend series, but the second novel hasn’t budged in a long time. Not sure what’s up with that – I have some notion of where the story needs to go – but I’m just not feeling the story the way I did with The Curse of Steel.
Meanwhile, a few days ago I went back and re-read what I had written of my novel Twice-Crowned, which I last worked on in about 2019. It’s about 22,000 words so far, and I find it’s actually pretty good for a rough draft.
Twice-Crowned is a bit of alternate-historical fantasy. It’s set in a world that looks a lot like Classical Greece, but with a few supernatural elements folded in, and a big point-of-divergence that is bending the course of history away from what we’re familiar with.
The notion is that there was a survival of the civilization we call “Minoan,” which got away from the sack of Crete by proto-Greeks and set up an enclave in the west. Where our history put the city-state of Syracuse, this alternate timeline has a city called Danassos. It’s a lot like other Hellenic poleis, with the very prominent exception that women are full citizens, holding property and exercising their own political rights and privileges. In one sense it’s a world-building exercise – how can I come up with a culture that’s plausibly Classical Greek and yet has the very non-Hellenic feature of (relative) gender equality? What consequences would that be likely to have as the history of the period unfolds?
I’ve been moved to spend a few days working on back story and research, with the result that I’ve got a fairly substantial timeline document and the start of some notes on how this imaginary society works. I think by this evening I’m going to package some of that up as a free release for my patrons, just to drum up a little interest in the project. Once that’s done, I need to get back to work on Architect of Worlds over the rest of June.
In the long run, I think Twice-Crowned may become my main literary project for the next few months, taking the place of The Sunlit Lands. Maybe if I can get that novel finished, I can come back to Krava’s Legend with fresh eyes.
Well, May didn’t go quite as planned. I originally planned to write the last open section of Architect of Worlds, but early in the month my muse decided to go and live on Mars instead. I ended up writing about 10000 words describing Mars in the Human Destiny setting, and giving myself a ton of new ideas for the universe and for fiction set therein. So my big project for May turned out to be a new partial interim draft of the Atlas of the Human Protectorate instead.
Okay, Mars is (more or less) out of my system now, so it’s back to Architect of Worlds for the month of June. Here’s the formal planning list for this month:
Top Priority:
Architect of Worlds: Write a section describing the structure of the galaxy and of interstellar space, and providing guidelines on how to make maps for interstellar settings. Also carry out further additions and revisions to the “special cases in worldbuilding” section. These two tasks are expected to give rise to a charged release, assuming they amount to at least 10,000 words of new material.
Second Priority:
Architect of Worlds: Further additions and revisions to the “working with astronomical data” section. May lead to a free v0.2 update, or may simply be integrated into v1.0 of the complete book.
Human Destiny: Continue compiling material for the eventual Atlas of the Human Protectorate.
Human Destiny: Design additional new rules systems for the Player’s Guide and add these to the interim draft.
Human Destiny: Begin work on a new Aminata Ndoye story.
Krava’s Legend: Review and possibly rewrite the existing partial draft of The Sunlit Lands, and write a few new chapters.
Back Burner:
Human Destiny: Finish the novelette “Remnants” for eventual collection and publication.
Krava’s Legend:Write the second short story for the “reader magnet” collection.
Scorpius Reach: Write a few new chapters of Second Dawn.
Scorpius Reach: Start work on a third edition of the Game of Empire rules for Traveller (or Cepheus Engine).
About the only change from the initial plan for last month is that I’m bumping a new Aminata Ndoye story up in priority a little. My main focus is going to be on Architect this month, but I may spend some time working on a story about Aminata’s first year at the Interstellar Service academy in France. Basically an immediate sequel to “Pilgrimage.”
Meanwhile, I’m continuing to tinker in my extensive spare time with QGIS and the NASA topographical data for Mars. I may work on one or two maps of 23rd century Mars for the Atlas, and if that works out it may yield a couple of free rewards for my patrons. We’ll see how the month goes.
The Shadow of Troy is the fifth volume of Empires of Bronze, Gordon Doherty’s ongoing historical fiction series set in the ancient Hittite Empire. This volume is a watershed for the series. Everything that has gone before now collides with one of the world’s great narratives: the story of the Trojan War.
The Shadow of Troy continues to follow Hattu, now king of the Hittites. In the previous novel, The Crimson Throne, we learned how Hattu defeated his wicked nephew and seized the Hittite throne, as a divine prophecy had long predicted he would. Unfortunately, the struggle decimated the Hittite army, and the once-powerful kingdom is barely able to defend its own borders. Worse, climate change and the movements of barbarians beyond the edges of civilization are beginning to threaten every great kingdom in the Bronze Age world.
It is at this moment that King Hattu receives a desperate cry for aid from an ancient Hittite vassal, the city of Troy. A Trojan prince has offended the powerful kings of the Ahhiyawans across the sea, abducting one of their wives and bringing her back to Troy. Long greedy for Troy’s wealth, the Ahhiyawans have come across the sea with a thousand ships, and the Trojans have called for their Hittite overlords to defend them.
Hattu has no army to spare, but he is honor-bound to answer . . . so he comes alone, with no one to support him but his son and heir Tudha, along with a few of his veteran comrades-in-arms. He may not have an army, he may not have much hope left, but he has decades of experience as a warrior and captain in one bitter struggle after another. The Ahhiyawans will not be wise to take him lightly!
Throughout this series, Mr. Doherty has consistently done a good job of working with what few original sources are available to us. In this story, he has nothing less than the Iliad to work with, along with the other works of the so-called Trojan Cycle. In The Shadow of Troy he does masterful work, weaving together familiar bits of myth and heroic narrative while telling the story from a foreign (that is, Hittite) perspective. For example, if you’re familiar with the Iliad, you’ll recognize a lot of very specific bits of action in the battle scenes.
The novel does interesting things with the mysteries of the narrative. Why did the Achaeans come to attack Troy – was it truly over something as simple as an unfaithful wife? Troy was almost certainly a Hittite vassal state, and in this story the Hittite king comes to support Troy in the war . . . so why does the Iliad say absolutely nothing about the Hittites? What was really going on with the Trojan Horse, and the final fall of the city?
Most of all, Mr. Doherty does something remarkable with the preordained conclusion of the story. Throughout the series King Hattu has never lost a war, even if his victories have come at terrible cost. He is clearly the hero of this story . . . and yet it’s a foregone conclusion that Troy will fall in the end. How The Shadow of Troy ties up all these threads is a treat to watch, even (or especially) if you’re already familiar with the Greek sources.
Mechanically, the novel works on several levels. The plot is tight, even though it has a few more twists and reversals than usual. There’s more moral ambiguity in this story than in the previous volumes – there are brave heroes and foul villains, but for once it’s not always clear which is which. There’s a superb subplot involving Hattu and his son, in which both characters get plenty of development as sympathetic protagonists. The prose style is very clean, with no copy-editing or other errors to pull me out of the narrative. In all, a very workmanlike job.
Readers should be aware, as always, that the story is set in a brutal and violent time. Descriptions of human cruelty and violence are common and very explicit.
I very much enjoyed The Shadow of Troy. I understand there will be one more book in the series, and I’m very much looking forward to seeing what Mr. Doherty does to wrap this story up. Very strongly recommended – an action-packed and bloody retelling of the Trojan cycle and what comes afterward.
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
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
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
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.
April came down to the wire, but on the last day of the month I was able to both post a book review and push out the first section of the Atlas of the Human Protectorate.
For the month of May, I think the Top Priority item is going to be Architect of Worlds again. There’s one more section of the book I need to write from scratch, and the “special cases” section needs more love. I suspect between those two items I’ll have plenty of new material, so a combination of them is likely going to be a charged release for the month of May.
The remarkable thing is that if I can hit that mark this month, that will mean that Architect of Worlds will be more or less complete, at least in an initial rough draft. That’s quite a milestone! I think if all goes well, June may see a release of a full rough draft of Architect, all in one document, a true v1.0 for the entire project. That will be a free release for my patrons, since they’ve already seen all the individual pieces.
The book won’t be anywhere close to finished at that point – I anticipate a lot of polishing, production of diagrams and graphics, and layout before I can even consider trying to publish it – but that’s still a big step forward. I begin to think there’s a chance Architect may arrive on virtual store shelves before the end of calendar year 2022.
All that being said, here’s the formal planning list for May:
Top Priority:
Architect of Worlds: Write a section describing the structure of the galaxy and of interstellar space, and providing guidelines on how to make maps for interstellar settings. Also carry out further additions and revisions to the “special cases in worldbuilding” section. These two tasks are expected to give rise to a charged release, assuming they amount to at least 10,000 words of new material.
Second Priority:
Architect of Worlds: Further additions and revisions to the “working with astronomical data” section. May lead to a free v0.2 update, or may simply be integrated into v1.0 of the complete book.
Human Destiny: Continue compiling material for the eventual Atlas of the Human Protectorate.
Human Destiny: Design additional new rules systems for the Player’s Guide and add these to the interim draft.
Krava’s Legend: Review and possibly rewrite the existing partial draft of The Sunlit Lands, and write a few new chapters.
Back Burner:
Human Destiny: Begin work on a new Aminata Ndoye story.
Human Destiny: Finish the novelette “Remnants” for eventual collection and publication.
Krava’s Legend:Write the second short story for the “reader magnet” collection.
Scorpius Reach: Write a few new chapters of Second Dawn.
Scorpius Reach: Start work on a third edition of the Game of Empire rules for Traveller (or Cepheus Engine).
Legends & Lattes is light fantasy, set in a tabletop-game-inspired fantasy universe that’s reminiscent of Terry Pratchett’s Discworld.
Viv is an orc warrior who has been living as an adventurer: delving in dungeons, slaying monsters, wielding a named sword of legend, the whole package. Unfortunately, age and old wounds are starting to get the better of her, so after one final big score she’s looking to reinvent herself wholesale. She moves to the big city of Thune . . . where she plans to open the first coffee shop ever seen there.
That’s it. That’s pretty much the whole story. And it is delightful, a slice-of-life tale that pulls the reader in and doesn’t let go.
The subtitle of Legends & Lattes is “A Novel of High Fantasy and Low Stakes,” and Mr. Baldree isn’t kidding there. There are a few tropes borrowed from more high-stakes stories: a mystery connected with Viv’s last great adventure, a conflict arising from her old dungeon-delving party, another conflict with local gangsters. Still, those elements of the plot are secondary. The real meat of the story is about Viv’s quest for a quiet, peaceful way to live out the rest of her life.
Viv has planned her move very carefully. She selects just the right location for her new venture, hires a contractor to renovate the building, sets up her gnome-designed coffee machine, and opens her doors. Of course, even with all her planning, she had no prior experience as a small-business owner or as a barista. Some things don’t work entirely as expected. As with all startup ventures, she soon suffers the “valley of death” in which all the money is going out rather than coming in. Still, some of the locals soon begin to discover the delights of well-made coffee.
Watching the mechanics of Viv’s startup is certainly fun. She encounters problems, places where her careful planning failed, and she must find ways to overcome them. Watching how Viv reinvents her social style is even more engaging. She quickly discovers that she can’t succeed on her own, any more than she could when she was slaying monsters for a living. Her encounters with potential customers, with business partners, and with new friends are worth the price of admission on their own.
Travis Baldree has a very clean prose style, and the editing here is top-notch. The story structure is very straightforward. Mr. Baldree sticks almost exclusively to third person close viewpoint and a single perspective, and the plot unrolls at a carefully measured pace. A very workmanlike debut novel here.
I fully enjoyed Legends & Lattes, and while I left with the sense that Viv’s story had come to a satisfying conclusion, I certainly wouldn’t object to discovering the existence of a sequel or three. Very highly recommended if you enjoy light Pratchettian fantasy.
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.
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 thecurrent 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.
