If enough data points trouble the theory, the theory may be wrong. If the theory is basic, the paradigm may have to change.

She sat down to eat. It was doubtful she had read his mind in that much detail. But a great pleasure nevertheless, to be able to meet her eye!

• • •

He got in the little cockpit with Peter and just after the timeslip they bounced down the bedrock runway, accelerating hard and tilting up at the black sky, the big streamlined space plane vibrating under them. Sax lay back, crushed into his seat, and waited for the plane to curve over that asymptotic hill at the top of its course, slowing as it rose less steeply, until it was in a gentle rise through the high stratosphere, making the transition from plane to rocket as the atmosphere thinned to its last attenuated level, a hundred kilometers high, where the gases of the Russell cocktail were annihilated daily by incoming UV rays. The plane’s skin was glowing with heat. Through the filtered glass of the cockpit it was the color of the sun at sunset. No doubt it was affecting their night vision. Below the planet was all dark, except for very faint patches of starlit glaciers in Hellas Basin. They were rising still. A widening gyre. Stars packed the blackness of what looked like an enormous black hemisphere, standing on an enormous black plane. Night sky, night Mars. They rose and rose again. The incandescent rocket was translucent yellow, hallucinatorily bright and sleek. The latest thing from Vishniac, designed in part by Spencer, and made of an intermetallic compound, chiefly gamma titanium aluminum, rendered superplastic for the manufacture of heat-resistant engine parts as well as the exterior skin, which dimmed a bit as they rose higher and it cooled. He could imagine the beautiful latticework of the gamma titanium aluminum, patterned in a tapestry of nodoids and catenoids like hooks and eyes, vibrating madly with the heat. They were building such things these days. Ground-to-space planes. Walk out into your backyard and fly to Mars in an aluminum can.

Sax described what he wanted to do next after this. Peter laughed.

“Do you think Vishniac can do it?”

“Oh yeah.”

“There are some design problems.”

“I know, I know. But they’ll solve them. I mean you don’t have to be a rocket scientist to be a rocket scientist.”

“That’s very true.”

Peter sang to pass the hours. Sax joined in when he knew the words— as in “Sixteen Tons,” a satisfying song. Peter told the story of how he had escaped from the falling elevator. What it had been like to float in an EVA suit, alone for two days. “Somehow it gave me a taste for it, that’s all. I know that sounds strange.”

“I understand.” The shapes out here were so big and pure. The color of things.

“What was it like to learn to talk again?”