a slow temperature rise until perihelion—and beyond—but that won’t concern us, because Endeavour will have had to leave long before then.”
“So it should soon be safe to go back inside?”
“Er—probably. We should certainly know in forty-eight hours.”
“A return is imperative,” said the Ambassador from Mercury. “We have to learn everything we possibly can about Rama. The situation has now changed completely.”
“I think we know what you mean, but would you care to elaborate?”
“Of course. Until now, we have assumed that Rama is lifeless—or at any rate uncontrolled. But we can no longer pretend that it is a derelict. Even if there are no life forms aboard, it may be directed by robot mechanisms, programmed to carry out some mission—perhaps one highly disadvantageous to us. Unpalatable though it may be, we must consider the question of self-defense.”
There was a babble of protesting voices, and the Chairman had to hold up his hand to restore order.
“Let His Excellency finish!” he pleaded. “Whether we like the idea or not, it should be considered seriously.”
“With all due respect to the Ambassador,” said Taylor in his most disrespectful voice, “I think we can rule out as naive the fear of malevolent intervention. Creatures as advanced as the Ramans must have correspondingly developed morals. Otherwise, they would have destroyed themselves—as we nearly did in the twentieth century. I’ve made that quite clear in my new book, Ethos and Cosmos. I hope you received your copy.”
“Yes, thank you, though I’m afraid the pressure of other matters has not allowed me to read beyond the introduction. However, I’m familiar with the general thesis. We may have no malevolent intentions toward an ant heap, but if we want to build a house on the same site….”
“This is as bad as the Pandora party! It’s nothing less than interstellar xenophobia!”
“Please, gentlemen! This is getting us nowhere. Mr. Ambassador, you still have the floor.”
The Chairman glared across three hundred and eighty thousand kilometers of space at Conrad Taylor, who reluctantly subsided, like a volcano biding its time.
“Thank you,” said the Ambassador from Mercury. “The danger may be unlikely, but where the future of the human race is involved we can take no chances. And, if I may say so, we Hermians may be particularly concerned. We may have more cause for alarm than anyone else.”
Taylor snorted audibly, but was quelled by another glare from the Moon.
“Why Mercury, more than any other planet?” asked the Chairman.
“Look at the dynamics of the situation. Rama is already inside our orbit. It is only an assumption that it will go around the Sun and head on out again into space. Suppose it carries out a braking maneuver? If it does so, this will be at perihelion, about thirty days from now. My scientists tell me that if the entire velocity change is carried out there, Rama will end up in a circular orbit only twenty-five million kilometers from the Sun. From there, it could dominate the solar system.”
For a long time nobody—not even Taylor—spoke a word. All the members of the committee were marshaling their thoughts about those difficult people the Hermians, so ably represented here by their ambassador.
To most people, Mercury was a fairly good approximation of Hell; at least, it would do until something worse came along. But the Hermians were proud of their bizarre planet, with its days longer than its years, its double sunrises and sunsets, its rivers of molten metal. By comparison, the Moon and Mars had been almost trivial challenges. Not until men landed on Venus (if they ever did) would they encounter an environment more hostile than that of Mercury.
And yet this world had turned out to be, in many ways, the key to the solar system. This seemed obvious in retrospect, but the Space Age had been almost a century old before the fact was realized. Now the Hermians never let anyone forget it.
Long before men reached the planet, Mercury’s abnormal density hinted at the heavy elements it contained; even so, its wealth was a source of astonishment, and had postponed for a thousand years any fears that the key metals of human civilization would be exhausted. And these treasures were in the best possible place, where the power of the Sun was ten times greater than on frigid Earth.
Unlimited energy, unlimited metal: that was Mercury. Its great magnetic launchers could catapult manufactured products to any point in the solar system. It could also export energy, in synthetic transuranium isotopes or pure radiation. It had even been