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Building Blueheart
a feature by Alison Sinclair

I like building worlds. In a sense, I do it for my living (or a part thereof): I write science fiction.

For my second novel, Blueheart, I built a world (also called Blueheart) that was almost entirely ocean, as setting for the conflict between human colonists who had been genetically engineered to live in the sea and the proponents of a millennial plan of settlement and terraforming for whom adaptation is merely an intermediate stage on the way to a final goal - and for whom the unity of humankind must be defended at all costs. I had certain requirements dictated by the plot and certain constraints dictated by physical laws - and the latter proved to have implications which affected the plotting. This is how it all worked out.

First, I went star-shopping. I wanted a good, steady, single mid-main sequence star within 20 light years of Earth. I wanted a mid-main sequence star because those are the stars current thinking says are most likely to support indigenous life, and part of the drama of Blueheart involved setting defenders of its pristine state against terraformers. And I had chosen to respect relativistic limits on attainable speed, which restricted how far out I could reasonably go and still have Earth an influence on its colonies. (Although if you want to break them, Stardrive will tell you how.)

I ended up poring over tables in the Sky Catalogue 2000 (Hirschfield and Sinnott), since the majority of popular astronomy books emphasised the visible stars, which were, for my purposes, unusable - too new for life to have evolved. I had to relax my distance criteria, since nearby space had too few stars to give me the total number of Earth colonies I wanted. My frontier shifted out to 40 light years.

I had been under the illusion that I could use the ancient world as a model for the effect of distance on political cohesion until an archaeologist friend pointed out that even at the height of the Roman Empire, a messenger could travel from London to Constantinople in a month. Information broadcast at the speed of light from Earth would take 40 years to travel to Blueheart, and my starships travelled at less than half that - which made the round trip between Earth and the frontier upwards of 200 years!

I had already decided on using suspended animation to extend the lives of space travellers; now I nudged the human life span for non space travellers upwards to just shy of 200 years. That, I thought, would not only let people stay around to await developments, but it would also encourage them to take more of a long-term view. I need that long-term view to play off as the adaptives of Blueheart began their challenge to the millennial plan of settlement and terraforming. But I did not want to nudge the life span up too far; I wanted these people to remain human, and to me the proximity of death - and the need to create an immortality that is not fleshly - is part of humanity. Death and religion also have their part in my story. However, the other consequence of the distance was that Earth and its inner colonies receded in importance, and the story came to be played out entirely on Blueheart. And that was to the good. Setting colonist against colonist - brother against sister and father against son - intensified the drama.

The star I picked was gamma Serpens, a G0 star about 42 light years out from Earth. There was a minor bonus with it - its nearest neighbour, lambda Serpens, was under seven light years away; thus I had an offstage wing for one of my main characters to enter from.

A G0 star is somewhat hotter and brighter than the Sun, but I decided not to do what I had done in my first novel Legacies, which was scrupulously adjust the orbit to ensure the planet received the correct amount of sunlight from the star I had chosen. That had caused me no end of grief, because the fact that the Burdanian year was two and a quarter years long had to be conveyed entirely by internal cues (Earth figuring nowhere in the story). My hereditary ruler was a young woman of nine, who had come to power as an adolescent of five - and I didn't get to explain these figures. On the suggestion of my editor, I gave the other planet in Legacies, Taridwyn, an Earth-length year, so it could at least be noted on several occasions that Burdania had a long year; nevertheless, I swore not to include such a basic difference again without some means of sign posting it. So Blueheart's year is an Earth year, more or less.

I had my star, and had adjusted to the implications of its distance. I had my planet. Now to water and seed it.

Water came first - Blueheart is a water world.

I picked on 97% water for the surface - and shortly thereafter found myself hamstrung by my own knowledge. The problem was this: Surface water, being both warmer and less salty, is less dense and will float atop the deep water. Life is largely restricted to the surface of the sea since life depends on photosynthesis, photosynthesis depends on light, and light effectively penetrates no deeper than 100 m. But when living organisms die, they sink, carrying the nutrients in their tissues into the dark, unliving depths. The surface becomes depleted of the nutrients which support life. On Earth, surface and deep waters are mixed by wind driving surface water away from continental barriers, which in turn forces upwelling of deep water - the seas in these areas are extraordinarily rich in life. But on Blueheart, I had no continents. The same mechanism occurs in mid-oceanic anticyclones, where surface water is driven outwards by the winds, drawing up deep water in the middle. But were those alone enough to sustain the rich ecosystem I wanted? I doubted it.

I had two solutions. I could make my seas very shallow, which for a number of reasons - including the viability of my undersea colonies, and the fact that I liked having dark mysterious depths in my oceans - I did not want to do. Or I could complain a lot, in hopes someone could convince me that my scruples didn't matter. (A third solution had been used by Joan Slonczewski in A Door into Ocean. Her water world's seas are mixed by the twice-yearly migration of immense "seaswallowers", to the peril of all inhabitants.) Eventually I complained to Tad Williams. He looked at me and said, "Well, why don't you put a false bottom on it?"

Put a false bottom on the sea?? Shock. Horror. Heresy. At first I was skeptical. Then I grew to like the notion. Combined with my reading about entire ecosystems of microscopic life living on flecks of floating debris, the idea of putting a false bottom on the sea led to Blueheart's floating forests, kelp-like plants with "roots" which intertwine in a dense under-mat to trap sinking dead matter. As an additional dramatic point, the floating forests could not coexist with the tides and breakers of a terraformed Blueheart, and they become a precious symbol to my main character and others.

Now to add some creatures that swim in the sea. The beauty of world-building is that we have a working world right underfoot. The diversity of life on Earth is stunning - we have lichen in the high arctic, sand grouse in the Sahara, vent worms in the depths of the sea. Relationships range from predator-prey, through mutual indifference, through public service (wrasses provide a parasite removal service to other fish) to symbiosis (the pairing of corals and photosynthetic bacteria). Sex, particularly in the ocean, comes in any number of permutations - animals that begin life as one sex and undergo a sex change, fish that keep harems, fish that form exclusive pair bonds, hermaphroditic invertebrates that copulate in chains ...

Aside from a general sense of how an ecosystem fits together, what I drew from natural history were examples for what was possible, how it was achieved and why - as well as specific ideas to "borrow". Blueheart's lava eels, for instance, have in their imaginative pedigree conger eels, barracudas, shellfish which sequester pigments from the algae they eat in their shells for camouflage, and creatures which reuse the poison-sacs from sea anemones in their own defence. Out of all that came the sea hunter's most dangerous prey, whose spines carry other animals' ingested poison - and a good rousing adventure between political crises.

My research also gave me insight as to how things look under sea. There are any number of beautifully illustrated books and gorgeously produced films on undersea life. From those, I learned about the turquoise light in clear tropical seas, and the pea-soup murkiness of waters rich in life. I learned how undersea life moves. I learned what colours to expect in reef fish - white, red, black, yellow - and what colours were uncommon. True blue pigments are very rare on Earth. In pure whimsy, I gifted Blueheart some blue and lilac fish, which are seen swimming in an aquarium in the office of the Director of the AOC, and mark his ambivalent fondness for the biosphere he advocates destroying.

Natural history also helped me in my creation of Blueheart's human water-dwellers, the adaptives.

I toyed with the idea of water breathing humans but the trouble with breathing water rather than air is that it does not have as much oxygen dissolved in it. The transfer of oxygen from water into the bloodstream is also much less efficient. It is probably more than an evolutionary accident that the large, intelligent animals of the sea are air breathing. I do not say it could not be done, but it would probably require drastic physical change, and my story demanded that the adaptations be done after birth or at least after conception. So my adaptives remained air breathers.

I used what was known about diving animals - whales, dolphins, seals, otters, and even crocodiles - to decide what my adaptives could do and how they would do it. Northern elephant seals can dive to depths of over 1 km, and stay submerged for over an hour. They are exceptional; most seals dive to 150 - 200 m, but that was quite enough for my purposes. They dive on a single lungful of air, storing oxygen in their tissues to avoid the nitrogen accumulations that cause the "bends".

Much of the background physiology I worked out never made it into the text of Blueheart - it was so commonplace to the lives of the characters that, like Burdania's long year, it needed no explanation.

I deliberately try to keep my background science as transparent as possible, recognisable to people who know something about the subject or care to study background, but unobtrusive to those who do not have that knowledge, or are primarily interested in the story. However, it informed how they would look (very red, with all that storage pigment in their tissues) what they could do, and whether it would be easy or - as is always good for drama - hard. And their ability to live independently in the sea was crucial to the central conflict of Blueheart, between the land dwellers and their millennial plan of settlement and terraforming, and the sea-dwellers with their independence and emergent culture. The alien setting and the story had to interlock for the novel to work not only as a story, but as a science fiction story, and, with accommodations on both sides, they did.

Further Reading

For discussions of planet building, see Poul Anderson "The Creation of Imaginary Worlds: The World Builder's Handbook and Pocket Companion," in Science Fiction, Today and Tomorrow, R Bretnor (ed) 1974, and more recently, World Building, Stephen L Gillett, 1996, one of the Science Fiction Writing Series by Writer's Digest Books.

© Alison Sinclair 1998

Elsewhere in infinity plus:

  • stories - Assassin.
  • non-fiction - Blueheart reviewed by John D Owen.
  • features - about the author.
  • contact - Alison's e-mail address is

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