He turned to Thrailkill, who had accompanied him. Normally an elected speaker presided over these sessions, but today they listened to him and naturally his host went along. “Is everybody here?” he asked.
Thrailkill’s gaze swept the room. Sunlight streamed in the windows, to touch women’s hair and men’s eyes with ruddiness. A quiet had fallen, underscored by rustlings and shufflings. Somewhere a baby cried, but was quickly soothed.
“Yes,” he said. “The last field expedition came in two hours ago, from the Icefloe Dwellers.” He scowled at Kahn. “I don’t know why you want this assembly. Our minds are made up.”
The spaceman consulted his watch. He had to stall for a bit. His men wouldn’t get down from orbit for some minutes yet, and then they must walk here. “I told you,” he said. “I want to make a final appeal.”
“We’ve heard your arguments,” Thrailkill said.
“Not formally.”
“Oh, all right.” Thrailkill advanced to the lectern. The PA boomed his words forth under the rafters.
“The meeting will please come to order,” he said. “As you know, we’re met for the purpose of officially ratifying the decision that we have reached. I daresay Captain Kahn will need such a recorded vote. First he’d like to address you.” He bowed slightly to his guests and took a chair. Leonie was in the front row with Vivian; he winked at them.
Kahn leaned on the stand. His body felt heavy and tired. “Ladies and gentlemen,” he said, “you have spent many hours this past night talking things over in private groups. Quite an exciting night, no? I have asked you to come here after sleeping on the question, because your choice should be made in a calmer mood, it being irrevocable.
“Hardly any of you have agreed to leave with us. I wonder if the majority have considered what their own desires mean. As was said long ago, ‘II faut vouloir les consequences de ce que Ton veut.’ ” Blankness met him, driving home how far these people had drifted from Earth. “I mean you must want the results of what you want. You are too few to maintain a culture at the modern level. True, your ancestors brought along the means to produce certain amenities, and you have a lot of information on microtape. But there are only so many heads among you, and each head can hold only so much. You are simply not going to have enough engineers, medical specialists, psychopediatricians, geneticists… every trained type necessary to operate a civilization, as opposed to a mere scientific base. Some of your children will die from causes that could have been prevented. Those who survive will mature ignorant of Earth’s high heritage.
“A similar thing happened before, on the American frontier. But America was close to Europe. The new barbarism ended in a few generations, as contact strengthened. You will be alone, but no more than one thin thread of radio, a lifetime passing between message and answer. Do you want to sink back into a dark age?”
Someone called, “We’ve done okay so far.” Others added remarks. Kahn was content to let them wrangle; thus he gained time, without drawing on his own exhausted resources. But Thrailkill shushed them and said:
“I believe we’re aware of that problem, Captain. In fact, we’ve lived with it during the whole existence of this… colony.” There, Kahn thought. He spoke the word. “We haven’t really been bothered. From what we hear about Earth, we’ve gained more than we’ve lost.” Applause. “And now that you’ve made us realize this is our home, this is where we belong, why, we won’t stay small. For purely genetic reasons we’ll have to expand our population as fast as possible. My wife and I always did want a houseful of kids. Now we can have them.” Cheering began. His reserve broke apart. “We’ll build our own civilization! And someday we’ll come back to you, as visitors. You’re giving up the stars. We’re not!”
They rose from their chairs and shouted.
Kahn let the noise surf around him, while he stood slumped. Soon, he begged. Let it be soon. Seeing that he remained where he was, the crowd grew gradually still. He waited till the last one had finished talking to his neighbor. Then the silence was so deep that he could hear the songbirds outside.
“Very well,” he said in a dull tone. “But what is to become of the Mithrans?”
Thrailkill, who had also stayed on his feet, said rapidly, “You mentioned that to me before, Captain. I told you then and I tell you now, the planet has room for both races. We aren’t going to turn on our friends.”
“My mate Bill Redfeather is an Amerind,” Kahn said. “Quite a few of his ancestors were friends to the white man. It didn’t help them in the long run. I am a Jew myself, if you know what that means. My people spent the better part of two thousand years being alien. We remember in our bones how that was. Finally some started a country of their own. The Arabs who were there objected, and lived out the rest of their lives in refugee camps. Ask Muthaswamy, my chief engineer, to explain the history of Moslem and Hindu in India. Ask his assistant Ngola to tell you what happened when Europe entered Africa. And, as far as that goes, what happened when Europe left again. You cannot intermingle two cultures. One of them will devour the other. And already, this minute, yours is the more powerful.”
They mumbled, down in the hall, and stared at him and did not understand. He sucked air into his lungs and tried anew:
“Yes, you don’t intend to harm the Mithrans. Thus far there has been little conflict. But when your numbers grow, when you begin to rape the land for all the resources this hungry civilization needs, when mutual exasperation escalates into battle—can you speak for your children? Your grandchildren? Their grandchildren, to the end of time? The people of Bach and Goethe brought forth Hitler. No, you don’t know what I am talking about, do you?
“Well, let us suppose that man on this planet reverses his entire previous record and gives the natives some fairly decent reservations and does not take them away again. Still, how much hope have they of becoming anything but parasites? They cannot become one with you. The surviving Amerinds could be assimilated, but they were human. Mithrans are not. They do not and cannot think like humans. But don’t they have the right to live in their world as they wish, make their own works, hope their own hopes?
“You call this planet underpopulated. By your standards, that is correct. But not by the natives’. How many individuals per hectare do you expect an economy like theirs to support? Take away part of a continent, and you murder that many unborn sentient beings. But you won’t stop there. You will take the world, and so murder an entire way of existence. How do you know that way isn’t better than ours? Certainly you have no right to deny the universe the chance that it is better.”
They seethed and buzzed at his feet. Thrailkill advanced, fists clenched, and said flatly, “Have you so little pride in being a man?”
“On the contrary,” Kahn answered, “I have so much pride that I will not see my race guilty of the ultimate crime. We are not going to make anyone else pay for our mistakes. We are going home and see if we cannot amend them ourselves.”
“So you say!” Thrailkill spat.
O God of mercy, send my men. Kahn looked into the eyes of the one whose salt he had eaten, and knew they would watch him for what remained of his life. And behind would gleam the Bay of Desire, and the Princess’ peak holy against a smokeless heaven, and the Weatherwomb waiting for ships to sail west. “You will be heroes on Earth,” he said. “And you will at least have memories. I—”
The communicator in his pocket buzzed. “Ready.” He slapped it once: “Go ahead.”
Thunder crashed on the roof, shaking walls. A deeptoned whistle followed. Kahn sagged back against the lectern. That would be the warboat, with guns and nuclear bombs.
The door flew open. Redfeather entered, and a squad of armed men. The rest had surrounded the hall.
Kahn straightened. His voice was a stranger’s, lost in the yells and cries: “You are still citizens of the Directorate. As master of an official ship, I have discretionary police authority. Will or no, you shall come back with me.”
He saw Leon
ie clutch her child to her. He ducked Thrailkill’s roundhouse swing and stumbled off the stage, along the aisle toward his men. Hands grabbed at him. Redfeather fired a warning burst, and thereafter he walked alone. He breathed hard, but kept his face motionless. It wouldn’t do for him to weep. Not yet.
And so end these chronicles of the folk who took the long road to the stars. And long it is, not at all like those here, nor the highways of other fictional universes. It is unlike them in another way, too. It is a road that is always open. It is real…
OUR MANY ROADS TO THE STARS
There are countless varieties of science fiction these days, and I would be the last to want any of them restricted in any way. Nevertheless, what first drew me to this literature and, after more years than I like to add up, still holds me, is its dealing with the marvels of the universe. To look aloft at the stars on a clear night and think that someday, somehow we might actually get out among them, rouses the thrill anew, and I become young again. After all, we made it to the Moon didn’t we? Mean wile, only science fiction of the old and truly kind takes the imagination forth on that journey. Therefore I put up with its frequent flaws; and so does many another dreamer.
But are we mere dreamers, telling ourselves stories of voyages yonder as our ancestors told of voyages to Avalon and Cibola? Those never existed, and the stars do; but, realistically, does any possibility of reaching them?
The case against interstellar travel traditionally begins with the sheer distances. While Pioneer 10 and 11, the Jupiter flybys, will leave the Solar System, they won’t get as far as Alpha Centauri, the nearest neighbor sun, for more than 40,000 years. (They aren’t actually bound in that direction.) At five times their speed, or 100 miles per second, which we are nowhere close to reaching today, the trip would take longer than recorded history goes back. And the average separation of stars in this galactic vicinity is twice as great.
If we could go very much faster—
At almost the speed of light, we’d reach Alpha Centauri in about four and a third years. But as most of you know, we who were faring would experience a shorter journey. Both the theory of relativity and experimental physics show that time passes “faster” for a fast-moving object. The closer the speed of light, the greater the difference, until at that velocity itself, a spaceman would make the trip in no time at all. However, the girl he left behind him would measure his transit as taking the same number of years as a light ray does; and he’d take equally long in coming back to her.
In reality, the velocity of light in vacuo, usually symbolized by c, cannot be attained by any material body. From a physical viewpoint, the reason lies in Einstein’s famous equation E = mc2. Mass and energy are equivalent. The faster a body moves, the more energy it has, and hence the more mass. This rises steeply as velocity gets close to c, and at that speed would become infinite, an obvious impossibility.
Mass increases by the same factor as time (and length) shrink. An appendix to this essay defines the terms more precisely than here. A table there gives some representative values of the factor for different values of velocity, v compared to c. At v = 7c, that is, at a speed of 70% light’s, time aboard ship equals distance covered in light-years. Thus, a journey of 10 light-years at 0.7c would occupy 10 years of the crew’s lives, although to people on Earth or on the target planet, it would take about 14.
There’s a catch here. We have quietly been supposing that the whole voyage is made at exactly this rate. In practice, the ship would have to get up to speed first, and brake as it neared the goal. Both these maneuvers take time; and most of this time is spent at low velocities where the relativistic effects aren’t noticeable.
Let’s imagine that we accelerate at one gravity, increasing our speed by 32 feet per second each second and thus providing ourselves with a comfortable Earth-normal weight inboard. It will take us approximately a year (a shade less) to come near c, during which period we will have covered almost half a light-year, and during most of which period our time rate won’t be significantly different from that of the outside cosmos. In fact, not until the eleventh month would the factor get as low as 0.5, though from then on it would start a really steepening nosedive. Similar considerations apply at journey’s end, while we slow down. Therefore a trip under these conditions would never take less than two years as far as we are concerned; if the distance covered is 10 light-years, the time required is 11 years as far as the girl (or boy) friend left behind is concerned.
At the “equalizing” v of 0.7 c, these figures become 10.7 years for the crew and 14.4 years for the stay-at-homes. This illustrates the dramatic gains that the former, if not the latter, can make by pushing c quite closely. But let’s stay with that value of 0.7 c for the time being, since it happens to be the one chosen by Bernard Oliver for his argument against the feasibility of star travel.
Now, Dr. Oliver, vice president for research and ‘ development at Hewlett-Packard, is definitely not unimaginative, nor hostile to the idea as such. Rather, he is intensely interested in contacting extraterrestrial intelligence, and was the guiding genius of Project Cyclops, which explored the means of doing so by radio. The design which his group came up with could, if built, detect anybody who’s using radio energy like us today within 100 light-years: Or it could receive beacon signals of reasonable strength within 1000 light-years: a sphere which encloses a million suns akin to Sol and half a billion which are different.
Still, he does not fudge the facts. Making the most favorable assumption, a matter-antimatter annihilation system which expels radiation itself, he has calculated the minimum requirement for a round trip with a stopover at the destination star, at a peak speed of 0.7c. Assuming 1000 tons of ship plus payload, which is certainly modest, he found that it must convert some 33,000 tons of fuel into energy—sufficient to supply the United States, at present levels of use, for half a million years. On first starting off from orbit, the ship would spend 10 times the power that the Sun gives to our entire Earth. Shielding requirements alone, against stray gamma rays, make this an absurdity, not to speak of a thousand square miles of radiating surface to cool the vessel if as little as one one-millionth of the energy reaches it in the form of waste heat.
Though we can reduce these figures a good deal if we assume it can refuel at the other end for its return home, the scheme looks impractical regardless. Moreover, Dr. Oliver, no doubt deliberately, has not mentioned that space is not empty. Between local stars, it contains about one hydro; gen atom per cubic centimeter, plus smalls-amounts of other materials. This is a harder vacuum than any we can achieve artificially. But a vessel ramming through it at 0.7c would release X-radiation at the rate of some 50 million roentgen units per hour. It takes less than 1000 to kill a human being. No material shielding could protect the crew for long, if at all.
Not every scientist is this pessimistic about the rocket to the stars, that is, a craft which carries its own energy source and reaction mass. Some hope for smaller, unmanned probes, perhaps moving at considerably lower speeds. But given the mass required for their life support and equipment, men who went by such a vehicle would have tp reckon on voyages lasting generations or centuries.
This is not impossible, of course. Maybe they could pass the time in suspended animation. Naturally radioactive atoms in the body set an upper limit to that, since they destroy tissue which would then not be replaced. But Carl Sagan, astronomer and exobiologist at Cornell University, estimates that a spore can survive up to a million years. This suggests to me that humans should be good for anyway several thousand.
Or maybe, in a huge ship with a complete ecology, an expedition could beget and raise children to carry their mission on. Calculations by Gerard K. O’Neill, professor of physics at Harvard, strongly indicate that this is quite feasible. His work has actually dealt with the possibility of establishing permanent, self-sustaining colonies in orbit, pleasanter to live in than most of Earth and capable of producing more worldlets like themselves from extraterrestrial resourc
es. He concludes that we can start on it now, with existing technology and at startlingly low cost, and have the first operational by the late 1980’s. Not long afterward, somebody could put a motor on one of these.
The hardened science fiction reader may think such ideas are old hat. And so they are, in fiction. But to me the fact is infinitely more exciting than any story—that the accomplishment can actually be made, that sober studies by reputable professionals are confirming the dream.
True, I’d prefer to believe that men and women can get out there faster, more easily, so that the people who sent them off will still be alive when word arrives of what they have discovered. Is this wishful thinking? We’ve written off the rocket as a means of ultra-fast travel, but may there be other ways?
Yes, probably there are. Even within the framework of conventional physics, where you can never surpass c, we already have more than one well-reasoned proposal. If not yet as detailed and mathematical as Oberth’s keystone work on interplanetary travel of 1929, the best of them seem equivalent to Tsiolkovsky’s cornerstone work of 1911. If the time scale is the same for future as for past developments, then the first manned Alpha Centauri expedition should leave about the year 2010____
That’s counting from R. W. Bussard’s original paper on the interstellar ramjet, which appeared in 1960. Chances are that a flat historical parallel is silly. But the engineering ideas positively are not. They make a great deal of sense.
Since the ramjet has been in a fair number of stories already, I’ll describe the principle rather briefly. We’ve seen that at high speeds, a vessel must somehow protect its crew from the atoms and ions in space. Lead or other material shielding is out of the question. Hopelessly too much would be required, it would give off secondary radiation of its own, and ablation would wear it down, incidentally producing a lot of heat, less readily dissipated in space than in an atmosphere. Since the gas must be controlled anyway, why not put it to work?
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