With their course set, Arcot spoke to the others. “Well, fellows, what are your opinions on—what we've seen? Wade, you're a chemist—tell us what you think of the explosion of the ship, and of the strange color of our molecular ray in their air.”
Wade shook his head doubtfully. “I've been trying to figure it out, and I can't quite believe my results. Still, I can't see any other explanation. That reddish glow looked like hydrogen ions in the air. The atmosphere was certainly combustible when it met ours, which makes it impossible for me to believe that their air contained any noticeable amount of oxygen, for anything above twenty per cent oxygen and the rest hydrogen would be violently explosive. Apparently the gas had to mix liberally with our air to reach that proportion. That it didn't explode when ionized, showed the absence of hydro-oxygen mixture.
“All the observed facts except one seem to point to an atmosphere composed largely of hydrogen. That one—there are beings living in it! I can understand how the Venerians might adapt to a different climate, but I can't see how anything approaching human life can live in an atmosphere like that.”
Arcot nodded. “I have come to similar conclusions. But I don't see too much objection to the thought of beings living in an atmosphere of hydrogen. It's all a question of organic chemistry. Remember that our bodies are just chemical furnaces. We take in fuel and oxidize it, using the heat as our source of power. The invaders live in an atmosphere of hydrogen. They eat oxidizing fuels, and breathe 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 sun-shade?”
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.”