Part 22 (1/2)

”Crypsis does.”

”Oh,” he said. ”This is your planet game.”

She often called it a game, but now she bristled at the cavalier label. ”Yes. That's what I'm talking about. The four-billion-year model.”

”All right, darling,” he said, attempting to project calmness.

”Mars,” she said. ”I always guessed Mars would be the problem. It's small and cools early, so you have to a.s.sume that its life forms would gain early toeholds everywhere.”

The wise course was to say nothing, which is what he did.

She continued, saying, ”I've always encouraged Earth and Mars and Venus to produce multiple life forms. Dozens, even hundreds of discrete biologies would emerge when the crusts cooled and water condensed. Each biology would align to local chemistries and temperatures. And on every world, everything eats the alien neighbors as well as every tasty cousin. The only winners are metabolically isolated, and only then if there was ample s.p.a.ce and a long timeline.”

The husband considered touching her hand. She had beautiful hands.

But she pulled away as soon as he tried.

”Two billion years,” she said, ”and everything looks fabulously reasonable.” She folded the hand in her lap. ”My model does offer a reason why we won't find homemade biologies on the Earth. Our DNA and amino acids are too efficient, too invasive. Our metabolisms have adapted to every available niche, which doesn't leave enough room for others.”

”Like in hot springs,” he said.

”No, our ancestors were born in the scalding places,” she told him. ”For them, adapting meant getting accustomed to cold temperatures, eating everything else down to supercooled salt.w.a.ter.”

”That's at two billion years?”

”Yes.” A distracted nod. ”And then the scenario turns bat-s.h.i.+t bizarre.”

Her husband's days were spent building rockets inside computers. He was very comfortable talking about models and their limitations.

Aiming to be helpful, he said, ”Perhaps you had too many variables.”

Her mouth tightened.

Sensing trouble, he reminded her, ”I am trying to help you.”

”I know.”

”What kind of collapse is it?”

”There isn't any collapse.”

”After two billion years, I mean.”

”I said, the scenario doesn't collapse.”

”Oh?”

”It remains stable all the way to the present,” she said.

”How many runs have you made?”

He imagined five. Five highly complicated simulations seemed like a healthy sampling.

But she said, ”Nineteen. And the twentieth is running now.”

Quietly, with feeling, the engineer said, ”Wow.”

There were many reasons to be emotional. But her temper abandoned her. She shrank a little, humility tempering her voice as her shoulders slumped, as she confessed to him, ”Each time, there is the same nonsense.”

Tweaks might fix five bad runs. But nineteen was a brutal number.

It took courage to ask, ”What exactly goes wrong?”

”Venus.”

”Venus?”

”Venus is ridiculous,” she said.

”Ridiculous,” he repeated.

”For starters, the planet is smaller and quicker to cool. That's why its ocean forms two hundred million years before Earth's ocean does. But Venus has more sunlight and more warmth everywhere, and according to my simulation, regardless what kind of life takes hold, evolution is quick and fierce.”

There was talk about a Brazilian probe to Venus. That wasn't his department, but he rather liked the subject.

”That doesn't sound unreasonable,” he said. ”Venus gets life, but then it becomes an oven ... when? One billion years ago, wasn't it?”

”Or earlier,” she said. ”Or maybe life survived another couple hundred million years. But that's the general timeline. And do you know what? Life might still be surviving there. The Russian Venera probes found bacteria-sized bodies at the alt.i.tude where Earth pressures and temperatures reign. Of course there isn't much water left, just sulfuric acid. And that's one reason why Crypsis has been chasing Venusians in acid baths across our world.”

The idea sounded familiar, or maybe he wanted to think so.

”People a.s.sume that Venus dies before life gets complicated,” she said. ”But in my nineteen simulations, without exception, Venus gets its free oxygen early on. Plus there's the added sunlight, the hotter climate. Photosynthesis brings an explosion of multicellular life. Our sister world could have been rich, probably for a billion years, right up until the sun grew too hot and shoved it over the brink.”

Her husband made another bid for the hand.

She let him take it.

Encouraged, he said, ”That is fascinating.”

She squeezed his fingers. ”The Earth has enjoyed a little more than half a billion years of evolution. Venus had a billion years. And in my scenario, without exception, the Venusians have plenty of time to leap into s.p.a.ce.”

”Leap how?”

She tugged at his ring finger, bringing pain. ”With rockets. Rockets like yours. You see, that's one of my basic a.s.sumptions. Where everybody else hunts for microbes, I invite intelligence and high technologies. But I already told you about that. Remember?”

”How long ago?” he asked.