“The Caress of a Butterfly’s Wing” Annotations

Warning: contains spoilers

General Notes

The story’s title is meant to represent the brevity of Mariposa and Daniel’s encounter, as well as referencing the sailfolk and their lightsail wings. Mariposa is the Spanish word for “Butterfly.” It’s been so long that I’m not sure I remember how the idea of sailfolk first occurred to me. I was probably considering how solar-sail craft would have to be stripped down to the bare minimum of mass, the logical extreme of which was removing the craft altogether and making the sail a second skin. That led to the question of why such extreme modification would be needed, resulting in the idea of castaways needing to adapt to survive. It’s most likely that I was influenced by the book Project Solar Sail, a collection of stories and essays on solar sails published in 1990 as a fundraising project for the World Space Foundation. Portions of that book are available online at Baen eBooks: http://www.baen.com/Chapters/9781625792112/9781625792112_toc.htm The story was originally set in the Diadem system, aka Alpha Comae Berenices, a binary pair of F5 main-sequence stars some 63 light-years from Earth. I decided on a binary system based on my research into sailing, specifically tacking. Tacking allows a boat to sail more or less upwind through a trick of physics, as explained at http://newt.phys.unsw.edu.au/~jw/sailing.html. If a boat’s sails are aligned at an angle to the wind, the wind is trying to push them sideways, but the water resists that sideways motion and creates a counterforce against the keel — and part of that force vector is directed forward due to the angle of the keel. So tacking requires two countervailing forces acting on the vessel. Thus, for maximum maneuverability, the sailors would need to be in a binary system, with the second star’s light pressure taking the place of the water pressure. Strictly speaking, this isn’t essential; I do mention that the sailfolk can maneuver outside the binary pair by using light pressure to move outward and “spilling wind” (turning their sails parallel to the direction of the light) to let the stars’ gravity pull them inward. But I liked the idea of tacking with two stars’ light and wanted to use it. Also, I needed the story to take place in a system without planets to settle on. At the time, back in 1998, it was still believed that binary stars would be unlikely to have planets because the gravitational influence of the stars would disrupt their formation. We now know this to be untrue. My original intent was that the castaways would be the descendants of the crew of a ramjet starship that had overshot its intended destination, with Diadem being the first star system they were able to reach, decades later. I think I gave up on this once I learned that ramships were unfeasible due to the drag their magnetic fields would create against the interstellar medium. The final version takes place further in the future and assumes the use of FTL drive to reach a much more distant, imaginary system. I gave up on Diadem because I wasn’t sure it was the right age to have the configuration of asteroids that I wanted (since they would tend to be gravitationally cleared out of the system or form into planets over time, in contrast to my original assumptions). I had trouble finding a real system that had the age and parameters I wanted, so I settled on an imaginary system too distant for us to have discovered it yet.

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p. 163 The sailfolk’s use of “wind” to refer to the light pressure from the stars is misleading, since it’s got nothing to do with the stellar wind, the outflow of diffuse plasma from a star. (Solar wind if it’s from our sun, Sol.) It’s the momentum of the light itself that accelerates lightsails like these. One can use the stellar wind to exert pressure against a magnetic sail, i.e. a loop of wire generating a magnetic field that the charged ions in the wind can push against. But I didn’t know that when I first wrote the story. So why would the sailfolk have chosen to use lightsails rather than magnetic sails? Perhaps because the accelerations of magnetic sails can be dangerously large, or perhaps because they require power to generate current. Or perhaps the winds in the Ogygia system are too turbulent. The stars are young and might therefore be unpredictably active. “The chill of vacuum” is a misleading phrase. Contrary to popular belief, vacuum is a fine insulator; you lose heat far more slowly in vacuum than in air or water, since there’s no medium to carry heat away by conduction or convection. As long as you’re in the direct light of a star, you’d experience space as quite warm. Astronauts and spacecraft generally need cooling systems to avoid overheating. However, although I wrote this line in error, it can be salvaged. A sailor like Mariposa has a very large surface area relative to her mass, so she’d radiate heat fairly quickly. Out in the Reaches, not only would the suns be more distant and provide less warmth, but she’d only be getting warmed from one direction, so her shadowed side would cool swiftly. Which is why she’s so much happier to be warmed from both sides at once. Aurelia is one of the sailfolk’s crèches. The first one was named Chrysalis, after the cocoon of a butterfly. Aurelia is an alternate name for a chrysalis. Kaze is the Japanese word for wind. Most sailfolk names involve wind, wings, sailing, and the like in various languages. An oldyear, of course, is an Earth year, a holdover term from the castaways’ history. p. 164 The system is named Ogygia after the island where Odysseus was stranded by the nymph Calypso in The Odyssey. Circe, of course, was a sorceress in the same work who turned Odysseus’s men into swine. (In the original version, the characters referred to Diadem’s stars as Diana and Demeter.) The Wandering Rocks are another Odyssean allusion, a hazard known as the Planctae, dealt with both by Odysseus and by Jason and the Argonauts. They are often confused with the Symplegades, the Clashing Rocks. Both were highly dangerous, moving rocks that could smash ships apart. Lagrange points, or Lagrangian points, are points of gravitational stability in a two-body system — L1 located between the two masses, L2 and L3 behind each mass relative to the other, and L4 and L5 forming equilateral triangles with the two masses. Typically, in a system where one body is much more massive than the other (e.g. Sun-Jupiter or Earth-Moon), the L4 and L5 points are stable (i.e. an object placed there tends to return there after being nudged away, like the bottom of a bowl) while the other three are unstable (i.e. an object perturbed away from the point will accelerate further away, like the top of a hill). However, if the ratio of the two bodies’ masses is less than 25:1, the L4 and L5 points are unstable as well. Ogygia’s two stars are approximately equal in mass, so the system would have no stable Lagrange points. This means that the geefolk habitats would need to use maneuvering thrusters to remain at the Lagrange points, as several past and current space probes have done in the Sun-Earth L1 and L2 points and the Earth-Moon L2 point. So why position the habitats there in the first place? Well, there would probably be a fair number of asteroids concentrated there at least temporarily, useful as sources of material. Or it might be about maintaining position relative to the two stars, so that the habitats would receive a constant level of heat and solar power. p. 165 The Song is one of my favorite parts of the worldbuilding in this story. I think my father, who was a big fan of contemporary and experimental music, would’ve loved the idea of a song that’s created in part by time lags and is experienced differently by every listener. I was influenced by my father’s composition “Dialogue for One,” a semi-improv saxophone piece that he performed using two reel-to-reel tape recorders with a single tape moving between them, so that his sax solo was recorded on one and then played back on the other several seconds later, allowing him to play counterpoint to his own previous melodies, with each phrase echoing repeatedly through the cycle and getting new elements added with each repetition. Over time, the overlapping patterns of notes would combine in unplanned ways and produce new patterns that would guide his sax improvisations and be added to the evolving cycle. This was certainly an inspiration for the way the sailors’ Song evolves. I’m afraid I don’t recall whether I ever discussed the Song in this story with him, though. When I rewrote the story recently, I was concerned that I did too much “walking to the plot,” too much introductory worldbuilding before the action set in. So I postponed the Song discussion to later in the story. However, my editor’s notes made it clear that  the up-front exposition about the long lightspeed time delays was necessary to make the events of the story clear to the reader, so I restored the Song discussion to its original position. p. 166 Argent means “silvery.” Spoiler alert: Mari’s concern about disease is foreshadowing for the climax of the story, but it’s disguised as irrational fear, hopefully hiding it in plain sight. I love it when storytellers reveal something right off the bat but obscure its meaning so that you don’t realize until the end that it was staring you in the face all along (as in The Sixth Sense, for instance). Whether I’ve actually pulled that off here is for the reader to decide. Samiel is an alternate name for the simoom, a hot, suffocating, sandy wind encountered in North African and Arabian deserts. I suppose I must’ve chosen the name to fit the harsh attitude of the character, but I don’t remember for sure. A spinnaker is a type of sail used by a yacht. The name is repurposed from a very different character in one of the earlier drafts (see below). A sun cycle is the orbital period of Circe and Calypso around each other. I assume it’s approximately the same as that of Diadem, about 26 years. So the castaways were stranded in the system at least 130 years before the story. p. 167 The passage about Mari’s voice echoing in future sailors’ ears is another foreshadowing of the climactic revelations.

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p. 167 The Robinson habitat is named after Robinson Crusoe, though I also intended it as a nod to the Robinson family of Lost in Space — who were, of course, named after the Swiss Family Robinson, who were in turn named in honor of Crusoe. p. 168 Sadiq is an Arabic name meaning “friend.” Habari gani is a Swahili greeting. As in “Among the Wild Cybers of Cybele,” there’s a prominent African presence in the starfaring civilization of this universe’s future. There’s also a subtle Kiswahili influence on the geefolks’ verb tenses, particularly the use of “did go” in place of “went,” “did rush” in place of “rushed,” etc. Kiswahili indicates tense by a particle/prefix added to a verb, so I used the helper word “did” in the same way for the past tense, paralleling “will” as a helper for the English future tense. The geefolk language has changed more from standard English than sailor language has. This is mainly because Mari is the viewpoint character and I wanted her speech to be clearer, but it makes sense, because a smaller, more isolated population like the sailfolk would have fewer influences acting to transform the language. Even though the geefolk are fairly isolated themselves, there are more of them living in several communities, so there are more opportunities for linguistic innovation.

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p. 168 The sail mesh is microscopic, on the same scale as the wavelengths of the suns’ light, so it can be adjusted to be more reflective or more transparent to a given wavelength depending on the size of the mesh. (Consider the door of a microwave oven, the grid of small holes behind the glass. These holes are smaller than a microwave wavelength but much larger than a visible wavelength, so that microwaves cannot get through the grid but visible light can.) Presumably, although Mari’s sails are quite thin, they have several microscopic layers and the fore and aft faces can be adjusted differently. p. 169 Another bit of foreshadowing here: “lifetimes of sailskin instinct.” p. 169-70 The use of “stroids” for “asteroids” is one of the few hints that this story takes place in the same reality as Only Superhuman, along with “cybers” for AIs eight paragraphs later. It suggests that the castaways’ ancestors were part of the Strider community of Sol’s Asteroid Belt, which would’ve aided their adjustment once stranded in a system without planets. I made this explicit in the Historical Overview appendix of Among the Wild Cybers. p. 170 The Spinward Void is meant to be a term used in the future for the Loop III Bubble, one of three low-density voids in the interstellar medium surrounding the Local Bubble in which our Sun is located. This is discussed at http://www.daviddarling.info/encyclopedia/L/Local_Bubble.html and at http://www.solstation.com/x-objects/chimney.htm. These bubbles are believed to have been formed by supernovae or by stellar winds from young, bright stars, blowing out voids of lower density in the interstellar medium. They’re the products of a wave of star formation that passed through this part of the Orion Arm within the past 30 million years. Stellar cartography is tricky because there are no real borders in space, so it occurs to me that the Local Bubble and Loops I – III could be used by interstellar civilizations to demarcate boundaries. The usage from which “Spinward Void” is drawn, along with the historical reasons for the Void’s abandonment, was established in a spec novel I’m currently marketing. (Update 12/31/22: This was a reference to the Arachne novels.) “And rescue would have been generations away in any case”: The assumption here is that there is faster-than-light drive but no FTL communications except for wormholes. Any beacon would’ve transmitted at the speed of light and taken centuries to reach civilization. (This is a major advantage over setting the story at Diadem, which is only 63 light years from Earth.) p. 171 Chrysalis is a spherical habitat carved from an asteroid and slowly rotating to provide minimal weight. Without much gravity, the trees would probably grow in irregular ways, but tree growth can be influenced by phototropism, the tendency of plants to grow toward the available light. Generally, the asymmetry in available light for a tree is minor enough that it’s overwhelmed by gravitotropism, the tendency of trees to grow vertically. But for trees growing in microgravity, phototropism would become a more significant factor in their growth, hence the trees striving toward the artificial sun. As for animal flight in microgravity, there have been some studies aboard aircraft using parabolic trajectories to create temporary free-fall conditions, and aboard the Mir space station. According to the paper “Disorientation of Animals in Microgravity” by Shigeo Mori, blindfolded birds in weightless conditions fly in backward loops — naturally enough, since they’re flapping their wings to create upward force to cancel the downward force of gravity, so without gravity they’d continously curve upward and end up going in circles. But without blindfolds, they’re able to adjust their flight — since, after all, birds routinely experience shifting g-forces and bursts of free fall as they fly and dive, so they’re adapted to adjust their flight as needed based on sensory cues. Insects are another matter. According to a NASA memo at http://www.bio.net/bionet/mm/bionews/1995-July/002285.html: Honey bees (Apis mellifica) were unable to fly normally and tumbled in weightlessness. House flies (Muscus domestica ) mostly limited themselves to walking on the walls. When they did fly, they apparently could control motion in all three axes, although flight only lasted for a few seconds. Moths (Anticarsis gammatalis) that developed in space, learned not to fly and preferred to float without wing beat. It’s possible that the insects and birds in Chrysalis were genetically engineered to cope better with microgravity. In fact, that was what I assumed in the original story until I turned up research suggesting that they could adapt without it. “learning to see the suns as down instead of up“: We’re used to the convention of representing the planets’ orbits horizontally with the sun in the middle, but for any space traveler within a star system, the star itself, as the largest gravitational source in the system, would be straight down, just as the Earth is down relative to an orbiting satellite or station. It helps to understand orbital dynamics and navigation if you keep this perspective in mind.

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p. 172 “They even spoke of God as something separate from themselves”: I fleshed out sailfolk spiritual beliefs in one of the earlier versions of the story, but most of that material proved extraneous in the final version. Basically, I gave them a highly ascetic faith based on self-abnegation and the embrace of what they called the Infinite. This ties into the way that many meditative and spiritual practices, as well as sensory deprivation, can lead to the suppression of activity in the parietal lobe, the part of the brain that gives us a sense of ourselves as separate from the universe. Without parietal activity, people tend to perceive themselves as transcending their bodies and being one with the universe or the divine. The majority of sailfolk life is lived in a state of sensory deprivation, and a sailor between maneuvers or ports has little need to be aware of one’s body anyway, so this kind of transcendent experience, called “communion with the Infinite,” would be basic to sailfolk spirituality. p. 173 I discussed the human need for physical contact and the cost of touch deprivation in my Only Superhuman annotations, p. 139 note. p. 175 Vayu is the Hindu god of the winds. Kipepeo is Kiswahili for butterfly.

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p. 177 The reference to Mari’s golden-bronze flesh is the only indication I was able to offer about her ethnicity, which may be just as well. I originally intended her to be Asian, but probably all of the sailfolk and geefolk alike are of mixed ancestry, since they descend from a small population (the Wrecked) that was clearly heavily multiethnic to begin with. The sailors have a smaller breeding base and shorter generations (due to shorter lifespans), so by now they’ve probably blended their forebears’ genes pretty thoroughly through their population. Thus, none of the sailfolk could be considered to have a specific Earthly ethnicity. Which means that this is, I believe, my second published story (the first being “The Weight of Silence”) in which none of the speaking characters are white.

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p. 180-2 In the first several versions of the story, Mari sacrificed her life to save Daniel and to experience intimacy with him, and that was it. Originally this was a response to my feelings about solitude and intimacy at the time I wrote the story; I was frustrated by my own shyness and isolation, and so I wrote a story whose protagonist had the courage to seize any opportunity for companionship at any cost. I was influenced in part by an experience I had at my 10-year high school reunion, which threatened to be lonely for me because none of my friends showed up. But I was approached by a very nice young woman named Amy, the girlfriend of a classmate, whom I’d never met before but who was very kind and warm and treated me like a real friend for the few hours we spent together at the reunion — but whom I never saw again afterward (even though I did try to make contact again). But even that brief, fleeting connection was very meaningful to me, and I decided to focus on how happy I was for the time I spent with Amy rather than how sad I was that it had been so brief. That experience informed Mariposa’s outlook, the idea that happiness could come in brief moments that should be cherished when they come. But Mari actually giving her life for a moment’s intimacy was a hard thing for editors to find plausible, so I adjusted the story to flesh out the reasons for it. In one draft, the sailors’ life became so ascetic and harsh that it became implausible that they’d ever accept such a lifestyle in the first place. That led to the draft that played up their spirituality and self-abnegation, but it still seemed like the geefolk were taking advantage of their selflessness. So I came up with the war backstory and the idea that Mari was taking this chance to heal the rift between the peoples. But when I revisited the story recently, I realized there was an unfortunate implication to the ending, in that the female lead sacrifices her entire existence for the male lead’s benefit. There’s a gendered power imbalance there that I hadn’t intended and that disturbed me when I recognized it. Fortunately, in attempting to revise the story for a cyborg-themed anthology, I came up with the idea of the sailors’ memories and minds being partly preserved in the sailskins, so that Mari’s sacrifice would not be total. And that led me to the idea of Daniel needing to make a sacrifice of his own in order to save her — and to save Kamila, who in earlier drafts had simply died in the accident. That way, both characters sacrifice to rescue each other, which not only solves the power imbalance and makes Daniel a less passive character, but makes it a better love story, I think.

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p. 183 Ogygia has “half-formed planets” because it’s a young system whose protoplanetary disks are still in the early stages of planet formation. I’m not sure I established this well enough in earlier parts of the story. In my longest draft, I actually showed what happened if a sailor lost bodily control. In this version, I used the name Spinnaker for a friend/lover of Mari’s who had trouble coping with the loneliness of sailfolk life, ultimately leading him to break down and either fatally lose control or commit suicide. I described it thusly: Where Spinnaker’s vast sail had been, there was now only a mangled clump of silver and a trail of fragments.  In his panic, he must have wrenched his limbs into motion, perhaps tried to curl up in a fetal ball, or to obey some atavistic urge to run.  The spars had snapped, the sails [had] torn, and their ragged remains had wrapped around him as he’d tumbled.  The spectroscopes caught traces of oxygen and water, but they may have been reserves.  Spinnaker may still have been alive in there, blind and deaf and mute with his antenna surface crumpled, with hundreds of layers of nanomesh piled on each other, vacuum-cementing into a solid crust.  But with so much damage to his skin, he wouldn’t be for long. In short, it was definitely a good idea to paralyze Daniel’s muscles.