“There’s a color between red and green,” Sax said when it appeared she was done talking about Miranda. “A mixture of the two. Madder alizarin, it’s sometimes called. You see it in plants sometimes.”

“Uh-huhn.”

“It makes me think of the political situation. If there couldn’t be some kind of red-green synthesis.”

“Browns.”

“Yes. Or alizarins.”

“I thought that’s what this Free Mars-Red coalition was, Irishka and the people who tossed out Jackie.”

“An anti-immigration coalition,” Sax said. “The wrong kind of red-green combination. In that they’re embroiling us in a conflict with Earth that isn’t necessary.”

“No?”

“No. The population problem is soon going to be eased. The issei— we’re hitting the limit, I think. And the nisei aren’t far behind.”

“Quick decline, you mean.”

“Exactly. When it gets our generation, and the one after, the human population of the solar system will be less than half what it is now.”

“Then they’ll figure out a different way to screw it up.”

“No doubt. But it won’t be the Hypermalthusian Age anymore. It’ll be their problem. So, worrying so much about immigration, to the point of causing conflict, threatening interplanetary war . . . it just isn’t necessary. It’s shortsighted. If there was a red movement on Mars pointing that out, offering to help Earth through the last of the surge years, it might keep people from killing each other, needlessly. It would be a new way of thinking about Mars.”

“A new areophany.”

“Yes. That’s what Maya called it.”

She laughed. “But Maya is crazy.”

“Why no,” Sax said sharply. “She certainly is not.”

Ann said no more, and Sax did not press the issue. Phobos moved visibly across the sky, backward through the zodiac.

They slept well. The next day they made an arduous climb up a steep gully in the wall, which apparently Ann and the other red climbers considered the walker’s route out. Sax had never had such a hard day’s work in his life; and even so they didn’t make it all the way out, but had to pitch the tent in haste at sunset, on a narrow ledge, and finish their emergence the following day, around noon.

• • •

On the great rim of Olympus Mons, all was as before. A giant cored circle of flat land; the violet sky in a band around the horizon so far below, a black zenith above; little hermitages scattered in boulder ejecta that had been hollowed out. A separate world. Part of blue Mars, but not.

The hut they stopped at first was inhabited by very old red mendicants of some sort, apparently living there while waiting for the quick decline to strike them, after which their bodies would be cremated, and the ashes cast into the thin jet stream.