During a discussion I participated in elsewhere , science-fiction world building spontaneously appeared in a discussion of another subject when a couple of people brought up the example of floating forests / floating islands. These have shown up in fiction before, and also in real life. I was inspired to add them to the Fermi Problems setting. When I had a notepad and a little time, I designed a planet to put them on and named it Tāwhiri.
What Is A Floating Forest?
When I say “floating forest” here, I mean a large mass of vegetation floating in a body of liquid. Perhaps there is too much similarity here to the micro-gravity asteroid-surrounding forests and floating aerogel-clumps that already feature in the setting, but I will include it anyway. It is relatively straightforward to produce a planet where such islands occur to a much greater extent than they do on Earth:
Consider an ocean gyre like the Sargasso Sea. Have masses of floating seaweed-equivalent that grow densely enough and stack thick enough to give a portion of the mass that is persistently well above the water line – avoids the photosynthesizing bits getting shadowed by or eaten by other stuff growing in the water. Then the clumps that are strong enough to avoid being disrupted by frequent waves/wind have a survival advantage, because they keep their energy supply more reliably. To get something that looks like a terrestrial forest, rather than a lumpy-mat-berg-plant-thing, invoke selection for traits that keep the clump in the gyre and so at a good latitude for growing. Growth dependence based on sunlight illumination patterns can do that, and progressively give “trees” with trunks and sail-leaves that adjust themselves unintelligently to take advantage of prevailing winds and stay in the gyre.
Some clumps will still escape, and either freeze in cold water or die in too-warm water or end up in another gyre. Clumps that get too big will fragment during storms, some will have die-offs due to competition between the various species that accumulate to form the colonies, some may capsize and persist as dead-or-dying rafts that can be colonized by new growth, and so on.
Tāwhiri – A Waterworld
But how to make a planet where these floating forest-mats are the tallest-standing lifeforms? We need to avoid having much land-based life to compete with. We need a waterworld.
There is a problem with making a world that is entirely covered in water: Carbon dioxide emitted from the mantle during volcanism enters the atmosphere/ocean, and acts as a powerful greenhouse gas. Unless it goes into making limestone or something similar, biosynthesis of carbon compounds only keeps so much of the carbon out of the atmosphere and only for so long. On the Earth, weathering processes on rocks exposed to the air create carbonate rocks, which eventually get subducted and return the CO2 to the mantle. If there is no exposed land at all, this process doesn’t work and the climate tends to run away into a steamhouse atmosphere, which is not conducive to abundant life. So I will do a little fine-tuning on the volatile content. The planet we are considering will have just enough water to cover all but 1% of the surface – we have various small exposed, largely volcanic, pieces of land; and larger relatively shallow areas of ocean that we would call submerged continental fragments if they were on Earth. This is enough to give a stable climate, albeit one with more CO2 in the atmosphere than we humans can breathe:
- Mass: 0.95 Earth masses
- Insolation: 340 W/m^2 average.
- Mean surface temperature: 300 K
- Atmospheric pressure: ~1.1 atm, 0.01 atm CO2
That surface temperature is a few degrees hotter than Earth was during the Permian, and is such that there are no ice caps at the poles. Some additional properties follow in part from the above and in part by arbitrary decision:
- Host Star: Kiwi – 0.85 solar masses, 0.43 solar luminosity
- a = 0.7 AU, year = 0.635 yr (291.4 local days)
- Mean solar day: 19h6m.
- Two satellites, each between 30% and 50% the mass of the Moon.
The relatively-shallow regions of the ocean also serve a useful setting function: they give a pattern of gyres and overall surface currents that is more-or-less fixed relative to the seafloor, rather than drifting around the planet. Keeping the maps straight will still be annoying, but at least a given gyre will stay over the same geology.
I am also pleased to assume people living in/on these floating forest-mats. Their cultures, history, anatomy, and evolution are not yet specified – this is a rapid once-through, after all.
But consider this technical problem: where do you get metal if you live on this world? There are several possible sources: those few areas of dry land that do exist, sulfide or hydroxide deposits on the sea floor, and some manner of catalytic process that separates out the metals dissolved in the sea water. The last has a terrestrial precedent: a ~3-cm snail called the scaly-foot gastropod that hangs out near some deep-sea vents:
So there are ways to start developing the hardware necessary to get off-planet and start expanding through space, although it would be somewhat more difficult than doing so on Earth. I will have the inhabitants of Tāwhiri in the Fermi Problems setting not have done this yet, in keeping with the large gaps in the setting between the number of places where life has appeared, the number of places where cultures have appeared, and the number of places where cultures have spread across large volumes.
There was a beautiful but terrible film with a bunch of blue aliens. I am not going to talk about that one any more. There was also a live-action film with the same characters, but that’s not it, either.
Avatar: The Last Airbender is a surprisingly good animated television series. Some things were awesome. Some things… make me wonder what just happened. As ever, here there be spoilers.
(Also, Michael did some significant writing for this one, since he knows stuff about martial arts.)
Bending in Avatar refers to four (or five) different sets of related styles of Supernatural Martial Arts, themed around the four Hellenic Classical Elements – air, water, earth, and fire. The different societies in the Avatar world are based around primary use of one element: Fire Nation, Earth Kingdom, the Water Tribes, and the Air Nomads (of whom Aang is the sole survivor for a long time). Despite the Hellenic division of the universe, the societies are predominately East-Asian themed: the Earth Kingdom is styled like classical China, the Fire Nation more like Meiji Japan, and the Air Nomads like Tibetan/Nepali Buddhists. The Water Tribes are a bit stranger: predominately Yupik/Aleut/Inuit, but a group in the equatorial swamp was greatly divergent.
One of the most fun things about bending, and why Rachel asked me to write this section, is how it is animated. The different elements are each associated with different real-life martial arts styles: water bending is based on various forms of tai chi (lots of redirection of motion), air bending on the less-well-known bāguàzhǎng (which focuses on evasion and smooth motions), fire bending on Northern Shaolin (emphasis on straight-line strikes), and earth bending on Hung Ga and related styles (deep solid stances). Like real-life martial arts, there are local variations in each style. This extends down to the level of individual characters, determined by their particular skills and who they were taught by. This is most prominent in the main characters and antagonists, but even bit characters get stylistic touches – some of the Earth benders incorporate American wrestling moves. Also like real-life martial arts, the techniques of bending aren’t restricted to humans. Some animals use them as well. Most prominently, there are flying bison, which stay airborne by air bending. Aang has one, Appa, as his companion. Appa is also the Gaang’s transportation (you see him above in the background).
The next cool thing is how bending is often exploited for mundane utility – water benders can do interesting healing tricks and build cities out of icebergs, the air benders had a global society based around towns that could only be accessed by flying, earth bending powers trains and heavy construction, fire bending becomes the basis of external combustion engines. These interlocking uses of magical and mundane technologies are reflected in relatively high life-expectancy and quality-of-life for human cultures that we would otherwise consider to be just at the edge of the industrial revolution (that and bending is apparently good for physical fitness).
The writers also made an effort to ensure competitive balance. Bending is only so capable (with the exception of the Avatars, who can move large islands around). Non-bending characters can equal or exceed what benders alone can do, either by engineering – such as The Mechanist, who builds gliders and dirigibles – or by subterfuge or by appropriate application of non-magical skill. The last sees the most air time in the show: super-accurate sword experts who can defeat all but the most powerful benders, knife-throwing to pin people in positions they can’t bend from, metal fans to wave fire bender flames out of the way, nerve strikes that temporarily paralyze and block bending. The last is a bit of a stretch for mundane martial arts, and is described as “chi-blocking”, so perhaps it counts as a fifth sort of bending.
There are a couple of problems with how bending is implemented. The most obvious is this: why is the Avatar the only one who can use more than one element? This gets into the Hindu concept of an Avatar as a reincarnating personification of universal power and the idea of bodhisattvas in some Buddhist schools, but just by itself it doesn’t make much sense. Zoku’s uncle Iroh (who is an awesome character) studied with water benders and incorporated some of their skills into his fire bending, although he did not learn how to bend water himself. But he did learn how to deflect lightning. Toph, the short Earth-bender punching things above, figures out how to bend metal. The background material explains that some people born in one nation are able to bend the theme element of another nation and not that of their own (which means that Aang will not be the last airbender forever). They usually immigrate or remain untrained and unable to use their power effectively. But why aren’t there any double-element or triple-element benders around?
The second problem is cultural. Why have the nations segregated themselves? Why don’t we have a more integrated society with air benders carrying the mail and other high-speed packages and working search-and-rescue; water benders handling hospitals and ocean freight; earth benders doing construction and land freight; and fire benders dominating large sections of manufacturing and the restaurant industry? Some of that could be justified historically, but given that the Avatars and the Four Nations have explicitly been around for over a thousand years, more cultural blending would be expected for the economics to be completely consistent. Related to the economics: in the Avatar world, both bending and mundane martial arts skill are egalitarian. The main Gaang has two young women and three young men, but the ratio becomes three to three when the recurring character Suki joins the group during the last few episodes. Several of the most dangerous antagonists are also women. Given this, why are the political and military leaderships of Fire, Earth, and Water still so male-dominated? Air was apparently more egalitarian, but everyone but Aang is dead during the series. We’ve touched on this problem before.
But even given those problems, Avatar still wins at world building in comparison to many other works, especially relative to other shows intended primarily for a young audience.
Character Development is Made of Win
I’m particularly impressed with how well the characters were developed. For instance, Sokka, the kid with brains but no bending, is appropriately snarky, but occasionally frustrated by lacking the raw power of his friends. He gradually transitions from being very goofy to having a more serious mien — though he never loses the sense of humor. Toph’s frustration with her parents and her desire for independence, which causes friction with the group, also work well. Even some of the minor characters have consistent appearance. The most entertaining is the guy trying to sell cabbages… and whose cabbages keep getting destroyed in various unfortunate ways. The appearance of airships is also nicely foreshadowed.
Zuko is particularly impressive. Over the course of the series, he transitions (with the mentorship of his uncle Iroh) from a teenager desperate to earn back his honor and his father’s love by capturing the Avatar to working against his father to save the world. There are a lot of bumps in the road, and I think it does a good job of illustrating the blurry line between good and evil. He shows both kindness and anger towards others in his travels. We learn he was loved by his mother, abused by his father, and constantly in conflict with his sister. He shows considerable internal conflict about changing sides, and has the appropriately rough reception when he presents the other kids with his change of heart. It takes all of the first two seasons and part of the third in order for him to get there. The rapid heel face turns we often see in movies always strike me as a bit… difficult to swallow. This more gradually transition is much easier to accept.
Wait, How Old Are These Kids?
Now, for the head-scratchers. While our heroes were developing mentally, there was a certain lack of physical growth.
Perhaps this makes sense for Aang — after all, he was twelve when he got stuck in the glacier, so maybe his growth has been permanently stunted by the experience. (Apparently this is actually canon, though it isn’t mentioned in the series.) On the other hand, there’s no such excuse for the other characters. Zuko may be done growing, but Sokka, Katara and Toph all start the series at around the age when they should be having a growth spurt. So, why does Sokka stay so much shorter than his dad for the whole series? Why does Toph, the youngest, stay so short relative to the other kids?
<michael>Related problem: the main character’s ages. Aang is physically 12-13 during the series; Toph is younger; Katara, Sokka, and Zuko somewhat older. But a lot happens during what is supposedly 12 months – crisscrossing the admittedly-small map many times, sieges and battles, near-death injuries and recoveries from them, lots of character development and changes in relationships, and Aang re-learning and mastering three styles of martial arts. This is all too fast. He learns fire bending last, but even so three weeks is simply not enough time to master a new set of motions. If the series had progressed in near-real-time, covering three or four years in-universe during its original run, things would have worked better. That would also have made the romantic sub-plots between Aang and Katara and Sokka and Suki more realistic, but would have made the lack of height changes more severe.</michael>
I See Dead People
This is okay, except that in their various adventures and battles against the Fire Nation, it really looks like our heroes have almost certainly killed some — but act as though they haven’t. Were there really no deaths in the Fire Nation ships you guys smacked, or the various fights against their soldiers, or when Aang went into Avatar super-powered mode at the North Pole, or when you assaulted the Fire Nation’s capital – smashing fortifications and tossing bombs into guard towers? Really?
Thus, it comes across as very strange when Aang has severe reticence against killing the Fire Lord after confronting him. He even says explicitly that he has never killed anyone before… when that is unlikely to be true, especially given the North Pole nastiness. Perhaps he means “deliberately” killed someone? It just doesn’t quite fit.
And that makes the ending all the more jarring. Where did that giant lion-turtle come from? Sure, they got a mention a time or two earlier in the story, but the sudden appearance of energy-bending (“bending each other”) really feels like a deus ex machina so that Aang can just de-power Fire Lord Ozai instead of killing him. It really feels like it came out of nowhere, especially since much of the discussion of plans earlier in the story focused on killing or defeating the Fire Lord.
This would have been much better if the ability to bend the energy of people had been mentioned… well, pretty much anywhere earlier in the story. Some sort of interesting ancient legend from before there was an avatar, for instance. That would have made this seem a bit less like a last-minute tweak to avoid having to kill a bad guy on-screen.
<michael>I propose that the mystic-energy-powered water bending healing and the chi-blocking nerve strikes were intended to be weaker derivatives of the energy-bending techniques, but that could have been better developed. Tougher problem: was permanently de-powering Ozai actually necessary to ensure he would not pose a threat in the future? If not, was it justified to do so? When is it ethical to invade someone’s mind/brain and rip out the parts that let them do something extraordinary? And what else can energy-bending do?</michael>
Despite having developed in entirely different environments, with entirely different histories, fictional cultures very often believe things that are similar to one or more human religions. Sometimes the similarity is nearly perfect. TVTropes calls that the Lowest Cosmic Denominator. For the particular case of Christianity being duplicated, it becomes “Crystal Dragon Jesus“. But does this make sense?
Note that there is a hard distinction between ethics and religion. Ethics is prescriptive statements about behavior. Religion is descriptive statements about the universe that assert some supernatural element. “I undertake the training rule to abstain from taking life” is an ethical statement. “If you murder, your self will spend its next incarnation in one of the Naraka realms” is a religious one.
Some things about religions in the fantasy literature make an abundant amount of sense. If there are zombies running around that a priest can turn back by waving a particular symbol, or if the armies of the Valar are fighting Morgoth across a continent, or if there is a reincarnating elemental-power kung-fu master saving the world every generation, it is quite obvious that something important is going on.
But this does raise a question of terminology: I have defined religion as characterized by belief in something supernatural. But if Aslan is running around the landscape fighting Tash, isn’t that automatically now part of the normal world? Belief in something we would call supernatural is irrelevant if it is an everyday occurrence. And religion no longer applies.
Terry Pratchett plays with this in Discworld. In that setting, gods exist, many of them. But they only have as much power as they have true believers. The Great God Om is significantly inconvenienced when he comes down to the Disc and finds that he only has one faithful follower left, leaving him incarnated as a maimed tortoise. Because most of the Discworld gods are gratuitously cruel, much of the population of the Disc is quietly Nay Theistic to avoid giving them more power than they have (“Of course they exist. But don’t go around believe’n in ’em. It only encourages ’em”). It’s rather like being in a city dominated by rival mafia dons: either you get one to protect you, or you keep your head down to avoid the attention. Vocal atheists tend to get hit by lightning by the gods that do have power, and so the surviving population of them are mainly fireproof golems. This being Pratchett, the social commentary is of course quite deliberate.
Human Religions in SciFi
When an author has incorporated religion(s) into a science fiction setting, particularly those set in the future, human societies tend to have those religions either be current ones or be similar in many ways. This makes sense if there has indeed been historical continuity, but it is important to remember that all real religions change dramatically over decades and centuries. Special mention here goes to Dune, where Frank Herbert took some liberties with Zen Buddhism and Sunni Islam to create the Zensunni adepts. Furthermore, Dune has the Bene Gesserit, who exploit religion for their own political ends – deliberately seeding legends on planets for the protection of their agents.
Herbert also did something very important with Dune: he did the research. Herbert was raised Catholic and became an atheistic Zen Buddhist later in life, but he took care to incorporate Muslim and Jewish as well as Christian and Buddhist elements into his world-building. That level of preparation is rare. It is far too easy to fall into Write What You Know while not doing the research and also into Author Appeal, and produce a fictional culture that is dominated by only a single religion that the author is familiar with or professes themselves or a complete lack of religion if the author is an agnostic or atheist. I do not have the statistics to back up the statement, but it seems to me that there is an excess of Christian themes in at least the English-language scifi and fantasy literature as compared to the actual worldwide distribution of religions (although this is perhaps offset by religion or the lack thereof not being that important in many scifi and fantasy works).
There is a related problem, where a fictional culture that is supposed to be one specific religion is portrayed as something else entirely. In Buffy: The Vampire Slayer and a lot of other works, Wicca is misrepresented. Going back a few decades and somewhat more abstracted, James Blish was significantly confused about 1950s Catholic doctrine when he wrote “A Case of Conscience“. There are far too many badly-intentioned examples. Some misrepresentation is people not doing the research. Some is people wanting to make a religion look as bad (or good) as possible.
For scifi aliens, there shouldn’t be anything exactly identical in an alien religion as compared to any human religion – there are two entirely different histories. Again, this is religion and not ethics. There are two themes that work as an excuse for there being too many identical elements: ancient astronauts or time travel. In Babylon 5, everyone thinks that the Vorlons look like angels. That was deliberately engineered by the Vorlons, who liked to go around the galaxy hacking the genetics of non-technological races so that they would like flying bilaterally-symmetric glowing figures. Babylon 5 also had a messianic religion centered around Valen, a Minbari prophet who said that he would return in the future. That was explained by Valen being a time traveler, Jeffrey Sinclair, who was born a thousand years later.
Other times there is a partial excuse for Crystal Dragon Jesus. If the religion of an alien culture is defined by the needs of the plot the writer wants to do, they will slant the world-building appropriately. Taking one more from Babylon 5: the Centauri were themed like the Roman Empire, so they have an extensive pantheon of various misbehaving gods and an imperial cult where emperors are elevated to godhood. In Star Trek: Deep Space Nine, the writers wanted to make the Captain into an actual messiah, so Bajor has a religion based around dual gods – good and evil – who are both actually Starfish Aliens that like to live inside wormholes. Captain Sisko becomes the emissary of the good ones (“The Prophets”), and disappears into heaven/closed time-like curves inside the wormhole at the end. Cargo Cults are popular in science fiction too, as a way for otherwise technologically-limited groups to have access to something without being able to replicate it.
But, these excuses for similarities aside, why should aliens have anything like human religions at all?
The origins of many individual human religions are argued. But a tendency to invoke supernatural explanations to phenomena is obviously common among humans, and has been for a very long time. Anthropological models of the development of religion describe religions as an emergent property or byproduct of known cognitive biases of human brains. We tend to assume correlation and causation even where neither exists, tend to falsely assume intelligent intent, and are easily manipulated by even entirely false fears. We fool ourselves into being more sure of our statements than we actually are, over-estimate how much others agree with us or how much we disagree with them, and like beliefs that we know others hold better. We also reflexively divide others into people in our group and outsiders, and favor the in-group over the out-group.
And so unless their members are very careful to avoid it, human societies quite rapidly develop numerous elaborate and very specific fictional scenarios to try and explain things that may not even exist. And things can get very dangerously confused when those different scenarios conflict with each other. To use TVTropes vocabulary again, religions are very devoted fandoms.
Would intelligent aliens necessarily have any of the same biases that we have? And if they didn’t have one or another, would religions as humans make them still appear or not? If not, what else might emerge instead?
Is some level of in-group favoritism inevitable for an intelligent species? Or can intelligence develop without it, automatically valuing all members of the species equally? What society evolves from that, and would something recognizably similar to human religions appear? Can we say that any religious institutions that do appear would be far less hierarchical, and perhaps far less important in society, if people did not often evaluate the needs of those who share particular beliefs in some supernatural concepts above those of those who do not?
Of course, given such a large difference in cognition, many things other than religion would be different. I played with this with the ursians, where over-valuing the in-group leads to a genetic diversity crisis quickly and so they have less such favoritism than humans do. This shows up in their sexual ethics, which are different from human norms because that was what optimized survival. But I have not considered what religions they might or might not have.
Pareidolia makes most of us prone to see human faces and figures and other patterns we consider significant everywhere. Clouds, sand dunes and hills, the shells of crabs, a colon and a single parentheses (parenthesis?). Some level of pareidolia is an evolutionary advantage: it is good for any animal to be sensitive to patterns corresponding to its prey, its predators, and others of its species. But consider an alien species with much less permitting pareidolia than we have. They would not have emoticons, and very different art. They would also not have people asserting that random patterns of char on toast was a miraculous appearance of a religious figure, or that the reflection of light off of a polished steel dome was a sign from God. Would such people still come up with anything we would call a religion? If so, what might it be like?
And one more:
Agent detection is the tendency to assume an intelligent intent where one does not necessarily exist. We do it very easily – just consider how we anthropomorphize even relatively simple devices, such as dice or a deck of cards. Taking a more complex system: when did you last complain that your computer is out to get you? This can be explained as having a survival advantage: anything that could potentially indicate actions by a predator or an adversary should be approached with caution, and false positives cost far less than false negatives.
I don’t think an intelligent species could evolve without some level of agent detection. Part of any successful intelligence has to be being able to identify other intelligences; wither to cooperate, confront, or avoid them. But like pareidolia, we could consider a species where the criteria for what makes them think “there is intent there” are more or less stringent or just different. How does that change a society, as well as any tendency for religions to appear or not?
Many of these questions may seem a bit abstract, but I think they’re useful to think about. Truly realistic alien cultures will differ from human norms in ways that are not simply derived from their environments, and recognizing and confronting the biases inherent in how we think shows some possibilities to explore. I’ve focused on religion or the lack thereof here, but this extends to everything that such aliens might think or do.
I think there is a dearth of good science fiction that explores these themes. We have space opera, where the aliens are often indistinguishable from humans in how they think. Other works have aliens whose thought patterns are said to be incomprehensible, but that usually seems to me as as excuse to skimp on the world-building. There is a large body of literature (including some of my own attempts) that explores how cultures and behaviors can be directly changed by the environment a species lives in, but that usually assumes ‘like humanity unless noted’. Given that Most Writers Are Human, it is hard to work through the implications of alien cognition consistently. Does anyone know of such a work?
Frank Drake’s formula for estimating the number of intelligent civilizations in the universe that could be located by SETI efforts has some limitations. But it does provide a convenient framework for thinking about the real search for extraterrestrial intelligence. And it can also be used to see the implications for the Fermi Problems setting of having two intelligent species within 15 parsecs of Earth.
The equation: Number of civilizations in the galaxy N = (number of stars)*(number of planets per star)*(fraction of planets where life evolves)*(fraction of biospheres where intelligence evolves)*(how long intelligence lasts)/(age of the universe)
There are some modifications here from the usual form of the equation. As I mentioned earlier, the usual definition of ‘intelligent’ for SETI is ‘having built a radio transmitter or other beacon readily detectable over interstellar distances’. Here I’m using a more comprehensive definition, which includes humans anytime since behavioral modernity has been around. And any one occurrence of intelligence lasts a long time. As a starting point, call it 1 million years.
Several of the numbers in the equation are known. The universe is 13.77 ± 0.06 billion years old, although I can round that to 10 billion for this because it takes a while for nucleosynthesis to work up to building enough non-hydrogen and non-helium material to make planets. There are ~300 billion stars in the galaxy – although there could be somewhat more depending on how we count brown dwarfs. The Kepler Mission and micro-lensing surveys show that there at least as many planets as there are stars. Again, the accounting here is difficult: the surveys are generally not sensitive to planets smaller than the Earth (to say nothing of asteroids – although they should be massively down-weighted compared to larger objects). Call the number of planets per star 3, to make the order-of-magnitude calculation easier.
So: In the Fermi Problems setting, N = 10^8 * (fraction of planets with life) * (fraction of biospheres that evolve intelligence). There are ~1900 stars in ~1400 stellar systems within 15 parsecs of Earth right now. If civilizations are uniformly distributed, which they may not be, for there to be two civilizations extant in that volume, there must be one civilization per ~700 stellar systems on average. I can make it 1 per 1000 stars without straining the odds. But N = 10^8 is 1 civilization per 3000 stars. This poses a problem.
What Should I Do?
There are five different variables I can adjust in the setting. The fraction of planets with life can’t be greater than one, and based on the evidence of our solar system it is most likely far less than 0.1. I could say that biospheres evolve intelligence many times, making that fraction greater than 1. Counting the apes, the dolphins, the elephants, the canines, the cats, the parrots, the corvids, and some of the cephalopods as separate evolutions of intelligence on Earth gives 8, but we are obviously by far the most extensive of the lot. It is pretty much impossible to get the product of those two fractions above 1, so I am left with three possible changes:
1. Intelligence lasts a long time. I have had the ursians be trapped at the bottom of a hole in high-tech social stasis for hundreds of thousands of years. Can I make it several million instead, to push the number up to 10^7 years? This starts to get problematic for the neari, who can spread across 15 parsecs in that time even with limited technology; and technological stasis does not apply for them. I don’t think I can push the lifetime up much further than that without the setting breaking.
2. There are more ‘planets’ per star. In addition to terrestrials and gas giants, I count large satellites like Europa and Titan and some appropriately-down-weighted number of asteroids. But, like the lifetime number, this can only go up so much. Maybe we count 15 places in the solar system rather than 8, but most of those are less appealing for biologically interesting chemistry.
This leaves the last option, which is the easiest in scientific terms, but much harder in terms of plot:
3. Move the neari and the ursians further away from each other and from Earth. Putting them each 150 pc away rather than 15 gives 1000 times as many stars. Then, with civilizations lasting a million years and 3 planets per star, (fraction of planets with life)*(fraction of life with intelligence) need only be 0.001 or so. In this version of the setting, one out of every 30 stars will have a biosphere near it somewhere – there will be strange microbes all over the place, and the nearest macroscopic ET organisms will be something like 30 lightyears away. And in places with fossil records, there will be ruins/remains of billion-years-dead cultures; far far more of those than the extant cultures.
If I do increase the distances so much, then there is no way for a neari comet boat to travel to Big Bear and find the ursians. And the timeline will need to be extended; with things involving humans and either group of aliens happening thousands of years in the future rather than only 500 years from now.
So, shall I change the setting to avoid the improbability of having not just two, but three civilizations so close together? The price is much less of characters meeting aliens in person, much longer time lags when talking to aliens remotely, and much more far-future exoplanet geobiology and archaeology. It seems that’s what the universe is like.
For the second alien species in the Fermi Problems setting, I decided to go with another take on the “Where are they?” line. Fermi’s argument for a spacefaring civilization spreading across the galaxy in only a few million years depends on a long period of nearly exponential growth and on a travel speed that is a significant fraction of the speed of light. My friend Jacob Haqq-Misra has worked out some limitations on the rapid growth of civilizations, but I decided to design aliens who could not travel at more than 0.001 c. This requires two things: a species that cannot handle high acceleration, and a technology base that does not allow them to either engineer themselves or robotic emissaries to accelerate faster or to build a rocket that can continuously accelerate for a very long time.
The latter is a rather severe limitation. Accelerating at 0.03 m/s^2, a spacecraft would still reach 0.003 c after 1 year and cover ~8 lightyears in a century if the acceleration was sustained. The later is unlikely for something internally powered: fusion rockets are limited to maybe 0.1 c peak speed, given the requirement to stop at the destination. Even a Bussard ramjet is limited to 0.119 c by the exhaust velocity of the fusion rocket. But I have set a speed limit of 0.001 c or 300 km/s. Even a fission-reactor-powered ion engine could in theory reach or somewhat exceed that speed. So, I needed to design a species that cannot handle high acceleration and can travel interstellar distances with nothing fancier than a chemical rocket. Taking some liberties with biochemistry, I propose a biosphere that evolved on small asteroids in the nominal habitable zone of a binary made of two M-dwarf stars. I picked CM Draconis because there is a lot of data available on it, it doesn’t have any large planets in the habitable zone, and it isn’t too close to Earth. Once again, I gave the fictional version of it a name in addition to the catalog listing: Druk. It happens that CM Draconis forms a hierarchical triple system with a white dwarf, GJ 630.1B, several hundred AU away. Continuing the theme, call it Wyvern.
I fully confess that the following is far more improbable than the ursians are, because the reservoirs for biochemistry to develop in are far smaller if for no other reason. With that caveat, I ask for any reasons why it is impossible, rather than merely incredibly improbable (levels of likelihood comparable to large-scale quantum tunneling may be counted as impossible). The improbable makes for good science fiction; the impossible is not allowed.
Consider a water- and carbon-rich asteroid, between a few hundred meters and a few tens of kilometers across. The particular object we are discussing doesn’t exist anymore, but it was like billions of others: a rubble-pile of variously-sized grains. Fine-grained material accumulates in dust ponds on such objects, and on a carbonaceous-chondrite object those grains will be rich in a slew of various relatively complex carbon compounds. This much is well-established.
The fictional assumption that I invoked was for there to be enough chemistry going on in those dust ponds (using monolayers of water molecules on the grain surfaces?) to produce small closed membranes durable enough to keep their contents separated from the surrounding grains and protected from being shaken off a grain into the surrounding vacuum while still being permeable enough to allow new molecules in. From there, chemistry proceeds to something that is self-catalyzing and rather like a protocell – similar to the bubble model of abiogenesis.
Given this admittedly out-there assumption, I can invoke evolutionary processes to expand this strange biosphere. Cells with vacuum-tight walls, high radiation tolerance, and specialized molecule-sized valves survive better; on the surfaces of the ponds as well as beneath them and inside ejected meteoroids. Photosynthesis takes over from feeding on primordial and cosmic-ray-seeded high-energy compounds. Heterotrophs feed on the plants and on each other; larger and better-armored multicellular plants enjoy a survival advantage and larger animals evolve to feed on them. Eventually, three-dimensional forests grow out from small cores – collecting a hundred times as much light as compared to if they only coated the rock. I was inspired to this design by some speculation by Freeman Dyson and possibly by some of the pictures in Le Petit Prince. Conveniently, these forests will be incredibly hard to observe over interstellar distances: they are dark in the visible, and infrared telescopes don’t have the same resolution as optical or radio arrays. Even if they are seen, the forests will be confused for boring dead carbonaceous asteroids until and unless their orbits are known well enough to measure their masses from mutual perturbations – showing how low their densities are.
The first rock was destroyed in a collision within a few hundred million years of the first appearance of life, scattering microbes across the system in the debris. Objects within the entire habitable zone have things growing on them; going too far out from the star causes un-insulated cells to freeze. On a timescale of a hundred million years, each individual forest is destroyed. On a much much shorter timescale, the plants break off rocket-propelled seed pods and solar-sail leaves that search for other objects using chemical-imaging tracers (the sail leaf idea was used by Larry Niven in the form of the ‘sail seed’). The animals that don’t have sufficient hibernation and delta-v abilities of their own hitch rides.
And, because I said there would be one, an intelligent species of animal evolved in one of the larger forests and then spread. I called them the neari – the etymology is a bit strained, but I hope it sounds cool enough.
Anatomy and Psychology
There is gravity, even on the smallest asteroids, although it can be effectively canceled for fast-spinning objects. The neari can handle continuous loads of ~0.03 m/s^2 without having too many problems, and can do brief jerks up to several gees. But they don’t have a physiologically preferred up and down or left-and-right, since the gravitational pull is a very gradual change as they navigate through the forests. So I designed a body plan for them inspired by sea urchins, crabs, and T4-bacteriophage: an icosahedral central body with limbs (equally validly called ‘arms’ or ‘legs’) at the vertices. The facets have specialized functions, but the neari are equally capable from all directions:
Four facets contain mouths, with airlock throats leading into a central stomach (the mouths are also used to excrete waste). Four are optical eyes, based around fish-eye lenses. Four have lines of infrared-sensitive pits. Four are blank on the surface, and underneath them are the neari’s central brain lobes. And four have organs that work only in near-vacuum: nose-eyes. This is an idea from Hal Clement: in vacuum, molecules travel long distances without collisions. So a pinhole camera can make an image in molecules as easily as in light, as long as whatever it is looking at is putting out any detectable number of particles. Neari exoskeletons and plant leaves smell only faintly. A comet outgassing is detectable tens of thousands of kilometers away – far further along its tail. An simpler version of this organ is used by the rocket pods and sail leaves to home in on objects.
The neari grow by molting and shedding their exoskeleton, a process which also allows the regeneration of limbs. Molting grows less efficient with time, and eventually accumulated damage leads to death – although prompt injuries will kill a neari far more quickly. The other way neari die is by giving birth. To solve the problem of exchanging genetic material and maintaining a pressurized environment for the embryonic neari to grow in, two neari (of any two of the three different sexes) join along the blank faces and slowly fuse together. The embryonic neari grow inside the merged exoskeleton, fed by their parents’ bodies.
These biological differences led to some important psychological differences between neari and humans (or ursians). Neari never know their parents – they are raised by their aunts/uncles and cousins. The individual is generally seen as less important compared to the family than it is for us. And sex is not a recreational activity. I have not fully explored how such different psychology will be reflected in neari culture. There is one other relevant psychological trait, from the hazard of being stuck in space just out of reach of a claw-hold: neari get very anxious if they aren’t holding onto something.
Culture, Technology, and Starships
The neari culture at Druk is in many senses less fragmented than that of the ursians, even though they’re spread out over cubic astronomical units. As of 70,000 BCE, you might have been tempted to call them a bronze-age culture. But there is no such thing as technological levels – real technological developments are spurred by the environment, the available resources and knowledge, and random moments of inspiration. The neari may have not have any metal other than nickel-iron, but they formed it into knives and hooks and parabolic focusing mirrors. Reflecting telescopes and heliographs gave light-speed communication across all of Druk, at least at telegraph-equivalent bandwidth. Writing preserved information. The neari had chemical rocketry, using rocket pods, and solar sails, made by cultivating and then trimming the leaves of sail plants. Travel between the forests, while slow and mass-limited, was inexpensive, and the neari understood Newtonian mechanics, radiation pressure, and numerical integration.
That said, the forests were isolated enough from each other that they retained very different cultures. Wars were not unknown, although they were limited in scope by the very low population density. Enough cooperation between forests did happen to organize large scale projects, including starships.
Druk has two red dwarf stars very close to each other, with an orbital velocity of ~75 km/s. With a little extra help from the super-jovian gas giant (>5 AU from the stars) and Wyvern (~500 AU), a careful gravitational slingshot maneuver past both stars can give an escaping interstellar spacecraft a velocity of ~300 km/s. And the neari already have things that can be turned into starships: comets (I got this idea from Greg Benford and David Brin). Several cubic kilometers of comet ice/organics contain ~3e16 J of usable chemical energy, enough to support 100 neari and their life-support system for tens of thousands of years. Select a comet about to make a close flyby of the stars, trim its orbit with high-speed impactors so that it gets ejected at high speed, jump on board before the flyby, afterwards adjust your trajectory using the gas giant or the white dwarf, and then burrow down under the surface for the long ride.
The problem with these comet boats is that they can only be targeted onto a certain range of trajectories, only a small fraction of comets are suitable (e.g. the comet has to be big enough to survive the stellar flybys), and the accuracy of the navigation can only be so good. The comets jet out gas unpredictably at perihelion, and even if the comet boat’s trajectory was known perfectly that of the destination star isn’t. The neari can measure parallax and proper motion accurately, but radial velocity is only approximate. A 0.1 km/s error at launch would be 1000 AU at arrival, and the comet boat can’t change its velocity by too much more than that en route.
For purposes of the setting:
The neari did start to spread across interstellar space ~70000 years ago – launching comet boats every few thousand years. But only one of them got close enough to its target star for the neari then on board to ditch the comet and stop. The others are either confirmed to be dead, still flying through the void, or unknown in status because they stopped replying to heliograph calls centuries ago. So Druk and Wyvern (the latter has a small debris disc out to a few hundredths of an AU from the star that the neari have settled) are still the main place to find the neari and there they are hard to see from parsecs away.
Does all of this work for a species that can travel over interstellar distances without being readily detectable, while simultaneously not spreading so fast that we should expect them to be here already?