Barbary

by Vonda N. McIntyre

  Her raft hung in a round room whose surface glistened like mother-of-pearl. The columns supporting the ceiling looked like frozen waterfalls or translucent pillars of melted glass. She searched for the opening that had let her in, but it had closed or sealed itself up. From the wind-chime sound transmitted to her through the raft’s body, she decided she must be surrounded by an atmosphere, but she did not know if it was oxygen or — as Heather had speculated — methane or cyanide. She had no way to tell whether it was safe to breathe, or poisonous.

  Mick miaowed again, louder.

  “It’s okay, Mick,” she said. She swallowed hard, trying to steady her voice. “It’s going to be okay.”

  “Do you hear us?”

  The radio spoke with the beautiful voice of the alien’s first message to Atlantis.

  “Yes,” she whispered, her throat dry. “Can you hear me?”

  “We sense you. Will you meet us?”

  “I want to. I really do,” Barbary said. “But I have to get Heather into zero g and back to the space station. She’s sick and I can’t wake her up. The gravity’s too strong for her here. Besides, all the important people are waiting to meet you, and they’ll be really angry if I see you first.”

  “But,” the voice said, “you have already seen us.”

  Barbary stared around the chamber, looking for creatures, great ugly things like the aliens in old movies, or small furry things like the aliens in books. They must be hiding behind the tall glass pillars.

  The gravity faded till it was barely enough to give Barbary’s surroundings a “down” and an “up.”

  “Is this gravity more comfortable for you?”

  “Yes,” Barbary said. “Thanks.”

  “We believed we calibrated your gravity correctly.”

  “You did,” Barbary said. “At least it felt okay to me. But Heather… Heather has to live in lower gravity. Won’t you let us go? She’s sick! Anyway, I can’t see you —” She stopped, amazed.

  Though she had not seen them move, the crystal columns had come closer. They clustered around her. Their rigid forms remained upright, yet they gave the impression of bending down like a group of worried aunts or friendly trees. A long row of crystalline fibers grew along the side of each column. The fibers quivered rapidly, vibrating against and stroking the main body of each being, producing the wind-chime voices.

  “Oh,” she said. “Oh. I do see you. You’re beautiful!”

  “We will loose your craft if you wish,” the voice on the radio said. “But our ship will reach your habitat before your vessel could fly to it, and here the gravity can be controlled.”

  “Can you hurry? I’m really worried about Heather.”

  “We will hurry.”

  Barbary listened to Heather’s rapid, irregular heartbeat.

  “Can’t you help her?” she said to the aliens. She remembered all the movies she had seen where people got hurt and aliens healed them. “Can’t you make her well? Aliens are supposed to be able to make people well!”

  “But we have only just met you,” one of the aliens said, perplexed and regretful. “We know little of your physiology. Perhaps in a few decades, if you wish us to study you…”

  Barbary thought she should have learned by now not to expect anything to work the way it did in books or movies. She leaned over Heather again, willing her to awaken.

  Heather’s eyelids fluttered.

  “Barbary…?”

  Heather opened her eyes. She sounded weak, confused, and tired.

  “It’s okay, Heather. Anyway, I think it is — what about you?”

  “I feel kind of awful. What happened?”

  “We’re on the alien ship.”

  A spark of excitement brought some of the color back to her sister’s cheeks. She struggled to a sitting position.

  “Are there aliens?” Heather whispered. She was shivering. Barbary chafed her cold hands and helped her put on the jacket.

  “There are other beings,” the gentle voice said. “We hope not to be alien, one to the other, for very long. Will you meet us?”

  “Can we breathe your air?” Heather hugged the jacket around her.

  “It is not our air. We do not use air. It is your air. You should find it life-sustaining, uninfectious, and sufficiently warm to maintain you.”

  Barbary gingerly cracked the seal of the roof-hatch. Warm, fresh air filled the raft. Heather took a deep breath. Her shivering eased.

  “If you join us,” a voice said, no longer from the radio but from one of the crystalline beings, “then we may rotate your vehicles and release the small person in the lower craft. It does not respond to our communications in an intelligible fashion, and it appears to be quite perturbed.”

  Barbary could not help it: she laughed. Heather managed to smile. Barbary picked her up — her weight was insignificant in this gravity — and carried her from the raft. The aliens made a spot among them for her; they slid across the mother-of-pearl floor as if, like starfish, they had thousands of tiny sucker-feet at their bases. The floor gave off a comforting warmth. Barbary laid Heather on the yielding surface.

  “I’m okay, I really am,” Heather said. She tried to sit up, but she was still weak. Barbary helped her, letting Heather lean back against her. Heather gazed at the aliens. “Holy cow.”

  Mick’s furry form hurtled across the space between the rafts and Barbary. He landed against her with all four feet extended and stopped himself by hooking his claws into her shirt. Somehow he managed to do it without touching her skin with his claws. He burrowed his head against her, and she wrapped her arms around him and laid her cheek against his soft fur.

  “Boy, Mick,” she whispered, “did you cause a lot of trouble.”

  She looked at the beings, who had rotated the rafts and opened the hatch of Mick’s with no help from her. They could have opened up her craft and plucked her and Heather out like peas from a pod, if they had wanted to.

  “Aren’t you mad?” she asked.

  “Our psychology differs from what we understand of yours, but we believe you would consider us sane.”

  “I didn’t mean mad-crazy. I meant mad-angry. We didn’t mean to bother you, but we had to rescue Mick.”

  “We comprehend this. We are not mad-angry,” the nearest being said. “How could we rouse ourselves to anger over actions taken in distress?”

  “Then how come you asked us not to approach you when you first called us?”

  “When a species advances beyond a certain point, it must be introduced to civilization. Otherwise it would discover galactic society, and the rules of galactic society, in a random way. This might cause it shock. Yet even when a people has reached a technological position of adequacy, it may not be ready in the psychological sense to meet other beings. We have found, through experience, that meeting new citizens is easier for them if they are in a large group of their own people. Then their fear of other beings, their xenophobia — which is inevitable in some degree — is acute. In this case, however, we recognized an emergency.”

  “Hasn’t anyone ever approached you before?”

  “Yes,” the being said. “Several times. But always with the aim of conquest or attack.”

  “What did you do to them?”

  “We showed them the futility of violence. Oftentimes disarming the aggressor is sufficient, though sometimes their aggression must be turned back upon them.”

  Barbary decided to leave questions on that subject till later. She wondered if she was ready to find out all the things the beings could do if they had to.

  But Heather felt braver, despite her pallor.

  “What rules did you mean?”

  “The rules that, beyond your own planet, you may create, but you may not destroy. You may observe, but you may not interfere.”

  Those rules sounded reasonable to Barbary. They sounded like what any sensible person would try to do.

  “A lot of people won’t like those rules,” Heather said, her expression troubl
ed. “They’ll want to break them.”

  “They will be persuaded to comply. There is no choice.”

  Heather leaned against Barbary, thoughtful and solemn. Barbary tried to think of something to say.

  Mick changed the subject for her. He had stopped burrowing into her armpit. He curled against her, purring and watching. Now he squirmed out of her arms and leaped into the air, coming down and bouncing ten meters away. He stalked up to one of the beings and sniffed its base — its feet? — then rubbed against its side. His fur stroking the crystal surface made an electric, musical note. The beings swiveled toward him, fascinated.

  “What a delightful feeling!” said the one that Mick had touched, “What a fine song the small person has invented.”

  “He’s pretty inventive all right,” Barbary said.

  “I do not wish to ask a rude question,” one of the beings said, “But why is the small person permitted to operate the vehicle? The controls have not been adapted to him.”

  “Um, that’s a long story,” Barbary said.

  “We love long stories. They help pass the time of travel between the stars.”

  Heather drew herself back from her troubled reverie. “How long have you been traveling?” she asked.

  “About a billion of your years.”

  “Your people have had space travel for a billion years?”

  “Oh, no, we have had space travel for a time an order of magnitude longer: for ten billion of your years. I thought you meant to ask how long we here had been exploring the stars.

  “Ten billion years of star travel,” Heather said. “You must be the oldest intelligent species in the universe.”

  “We have not found any older, but we search, and hope.”

  Heather stared at the beings in awe. “No wonder you like long stories.” She tried to smile. “Barbary, you can show them magic tricks.”

  “Magic? You have begun to use technology… yet you believe in magic?”

  “Not real magic, that’s just what it’s called.” Barbary tried to think of a quick way to explain, but gave up. “Um, it’s another long story.”

  “How excellent,” the being said. “We will look forward to hearing it.”

  “I’m Barbary,” Barbary said, remembering her manners, “and this is Heather, my sister. And the — the small person is Mickey.”

  “We do not have names, as you know them,” one of the beings said. “Each of us forms impressions of all others, and refers to the individual by the position in the image.”

  “That sounds complicated,” Barbary said

  “Not as complicated as recalling so many individual designations,” the crystal being said. “Without a pattern, how do you tell each other apart?”

  Barbary, who had been trying to fix in her mind the variations between the beings so she could remember each one’s name — if they had had names to tell her — looked over at Heather. They both burst out laughing.

  The delicate filaments on each being quivered and twined, and multitudes of wind-chime voices rang. At first Barbary wondered if she had hurt their feelings by laughing, and then she believed the beings were laughing along with her.

  “Another ship is approaching,” the musical voice said. “The beings within appear to be… quite perturbed.”

  “They don’t know what’s happened to us,” Heather said. “They probably think we’ve been swallowed up.”

  “As indeed you have.”

  “To be eaten, I mean.”

  “No. We do not ingest organic molecules. Will you speak with them?”

  “Can we? Please?” Heather said. “My father will be worried.”

  “Should we?” Barbary said.

  “Of course we should!” Heather said. “What do you mean?”

  “Maybe if they worry about us a little more, they won’t be so mad at us when we go back.”

  “If they’re going to be mad, they’re going to be mad,” Heather said. “I don’t want Yoshi to be worried anymore and I don’t want anybody out there to do anything that the other beings might think they need to be shown is futile.”

  “Okay,” Barbary said.

  “Would you like to speak to them now?”

  “Yes, please,” Heather said.

  “They will hear you.”

  Barbary saw no radio equipment, no change in the chamber to indicate a transmitter.

  “Hi, this is Heather,” Heather said to the air.

  “Heather!” Yoshi said. “Are you all right? What about Barbary?”

  “I’m okay.”

  “So am I,” Barbary said. “And so is Mick.”

  “What’s happening in there?” Jeanne asked.

  Barbary looked at Heather, who gazed back at her and smiled.

  “We’re with the — the beings in the starship,” Barbary said. “They’re bringing us home.”

  Artificial Gravity: Which Way Is Up?

  John G. Cramer

  The space station doughnut of 2001 and the O’Neill space-habitat cylinder have become part of the furniture of science fiction, so much so that we take spin-generated artificial gravity to be interchangeable with the Earth-normal variety in which we live. But there are differences that would be quite apparent to anyone living in the spin-generated variety. The subject of this AV column is an exploration of the differences between the “natural” gravity of Earth and the “artificial” gravity of a rotating space station.

  My interest in the physics of space station gravity developed because last year Vonda McIntyre was writing a book with a space station setting, and she asked my advice. The book, Barbary, is about a teenager who leaves Earth to live in a space station with spin-generated gravity. I helped Vonda in a very minor way by identifying the physical effects that the heroine would experience in that environment. What’s it like to ride an elevator in a space station? How would a ball game look if it were played there? If you woke up in a strange location, what simple tests would tell if you were in a rotating space station rather than at rest on the ground? And so on... I found that there are some interesting side-effects of artificial gravity, perhaps well known to NASA experts but obscure to the rest of us. And I was surprised to find that some recent SF hasn’t been too accurate in describing the space habitat environment.

  Looking at the world from a rotating vantage point (be it a merry-go-round or a space station) is odd and confusing. So let’s start with a simple concrete example. Suppose that we are on a doughnut space station, about half the size of the big one in 2001, providing living and working space at earth-normal gravity (1 g) for about 150 people. Such a station might take the form of a “wheel” 15 m wide and 160 m in diameter, rotating on its axis so that it makes a full rotation every 18 seconds. Because the floor of the space station rotates through its full circumference in this time, it has a speed (called the tangential velocity because the velocity lies along the tangent of the circle of travel) of 27.9 m/s. A note here on scaling to other sizes: If the station had 4 times this diameter, the rotation period to give 1 g of artificial gravity would be twice as long and the speed of the floor would be twice as large.

  Let’s do a simple “Mr. Science” experiment in this space station. Place a phonograph turntable on floor and use it to spin a cake pan filled with water. Let’s use a cake pan 40 cm in diameter and spin it at the 78 RPM setting of the turntable. The outer edges of the spinning cake pan will be moving at a speed of 1.6 m/s with respect to the floor. Therefore, the edge of the cake pan towards one outside wall of the station is traveling at an absolute speed of (27.9+1.6)=29.5 m/s, while the opposite edge of the pan has a speed of (27.9-1.6)=26.3 m/s. The pull of artificial gravity depends on the square of this tangential speed, so the “fast” edge experiences an increased pull of 1.12 g, while the pull on the “slow” edge decreases to 0.89 g. The water in the pan will tend to tilt, climbing higher on the slow edge and dropping lower on the fast edge. A spinning gyroscope would tumble in the same way, making the toy top a poor gift for a space child.
And so we see different physical effects in the artificial gravity of a space station than would be found if the same experiments were performed in the “natural” gravity of Earth.

  This simple experiment has an interesting implication for the psycho-physiology of human balance. Our equilibrium and our perception of vertical orientation come from the interaction of the fluid in the semicircular canals of our inner ears with the nerve fibers there. The vertigo experienced during and after spinning in an amusement park ride demonstrates what happens when this mechanism is disturbed. Seasickness is another example. Now suppose that you stand looking spinward down the long upward-curving hall along the rim of the space station, and then rapidly turn your head clockwise so that you are looking at the side wall to your right. Your head has made a rotation similar to that of the pan on the turntable. The fluid in your semicircular canals will therefore rise on one side and drop on the other as the water did. The subjective consequence is that you will “see” the floor tilt to the left, with the right side wall “rising” and the left side wall “dropping” momentarily. The amount of perceived floor tilt depends on the ratio of ear-velocity to floor velocity, but for any but the very largest of space stations the tilt sensation will be a quite unmistakable. This effect is likely to be fairly disorienting and may be a source of nausea and vertigo for the “greenhorn” who has just arrived from “natural” gravity. For the experienced space station inhabitant, however, the “floor-tilt effect” will become a useful aid to orientation because it will allows the user to tell whether he is looking “spinward” (in the direction that the floor is moving due to the spin) or “anti-spinward” (against the floor velocity) down the hall.

  Head twisting and nodding will also produce other subjective effects. Facing a wall at right angles to the spin direction and doing a similar head twist will make the floor seem to tilt up or down. Nodding or wobbling your head will produce similar effects. Placed in a small closed room, the experienced space station dweller can establish his orientation with respect to the spin of the station with a few twists of his head.