The Black Star Passes by John W. Campbell (read e book .txt) 📕

a reducing atmosphere; they have the two fuel components together again, but in a way different from our method. Evidently, it’s just as effective. I’m sure that’s the secret of the whole thing.”

“Sounds fairly logical.” Wade agreed. “But now I have a question for you. Where under the sun did these beings come from?”

Arcot’s reply came slowly. “I’ve been wondering the same thing. And the more I wonder, the less I believe they did come from⁠—under our sun. Let’s eliminate all the solar planets⁠—we can do that at one fell swoop. It’s perfectly obvious that those ships are by no means the first crude attempts of this race to fly through space. We’re dealing with an advanced technology. If they have had those ships even as far away as Pluto, we should certainly have heard from them by now.

“Hence, we’ve got to go out into interstellar space. You’ll probably want to ram some of my arguments down my throat⁠—I know there is no star near enough for the journey to be made in anything less than a couple of generations by all that’s logical; and they’d freeze in the interstellar cold doing it. There is no known star close enough⁠—but how about unknowns?”

“What have they been doing with the star?” Morey snorted. “Hiding it behind a sunshade?”

Arcot grinned. “Yes. A shade of old age. You know a sun can’t radiate forever; eventually they die. And a dead sun would be quite black, I’m sure.”

“And the planets that circle about them are apt to become a wee bit cool too, you know.”

“Agreed,” said Arcot, “and we wouldn’t be able to do much about it. But give these beings credit for a little higher order of intelligence. We saw machines in that space ship that certainly are beyond us! They are undoubtedly heating their planets with the same source of energy with which they are running their ships.

“I believe I have confirmation of that statement in two things. They are absolutely colorless; they don’t even have an opaque white skin. Any living creature exposed to the rays of a sun, which is certain to emit some chemical rays, is subject to coloration as a protection against those rays. The whites, who have always lived where sunlight is weakest, have developed a skin only slightly opaque. The Orientals, who live in more tropical countries, where less clothes and more sun is the motto, have slightly darker skins. In the extreme tropics nature has found it necessary to use a regular blanket of color to stop the rays. Now extrapolating the other way, were there no such rays, the people would become a pigmentless race. Since most proteins are rather translucent, at least when wet, they would appear much as these beings do. Remember, there are very few colored proteins. Hemoglobin, such as in our blood, and hemocyanin, like that in the blue blood of the Venerians, are practically unique in that respect. For hydrogen absorption, I imagine the blood of these creatures contains a fair proportion of some highly saturated compound, which readily takes on the element, and gives it up later.

“But we can kick this around some more in the lab.”

Before starting for New York, Arcot had convinced the officer in charge that it would be wise to destroy the more complete of the invaders’ ships at once, lest one of them manage to escape. The fact that none of them had any rays in operation was easily explained; they would have been destroyed by the Patrol if they had made any show of weapons. But they might be getting some ready, to be used in possible escape attempts. The scientists were through with their preliminary investigations. And the dismembered sections would remain for study, anyway.

The ships had finally been rayed apart, and when the three had left, their burning atmosphere had been sending mighty tongues of flame a mile or more into the air. The light gas of the alien atmosphere tended to rise in a great globular cloud, a ball that quickly burned itself out. It had not taken long for the last of the machines to disintegrate under the rays. There would be no more trouble from them, at any rate!

Now Morey asked Arcot if he thought that they had learned all they could from the ships; would it not have been wiser to save them, and investigate more fully later, taking a chance on stopping any sudden attack by surviving marauders by keeping a patrol of Air Guards there.

To which Arcot replied, “I thought quite a bit before I suggested their destruction, and I conferred for a few moments with Forsyth, who’s just about tops in biology and bacteriology. He said that they had by no means learned as much as they wished to, but they’d been forced to leave in any event. Remember that pure hydrogen, the atmosphere we were actually living in while on the ship, is quite as inert as pure oxygen⁠—when alone. But the two get very rough when mixed together. The longer those ships lay there the more dangerously explosive they became. If we hadn’t destroyed them, they would have wrecked themselves. I still think we followed the only logical course.

“Dr. Forsyth mentioned the danger of disease. There’s a remote possibility that we might be susceptible to their germs. I don’t believe we would be, for our chemical constitution is so vastly different. For instance, the Venerians and Terrestrians can visit each other with perfect freedom. The Venerians have diseases, and so do we, of course; but there are things in the blood of Venerians that are absolutely deadly to any Terrestrian organism. We have a similar deadly effect on Venerian germs. It isn’t immunity⁠—it’s simply that our respective constitutions are so different that we don’t need immunity. Similarly, Forsyth thinks we would be completely resistant to all diseases brought by the invaders. However, it’s safer to remove the danger, if any, first, and check afterward.”

The three men sped rapidly back to New York,