“I’m trying to understand the climate here. Back home there were astronomical effects on climate.”
Without leaving his seat Antonio seemed to strike a pose. Something in his voice changed. “You are remembering Milankovitch cycles.”
Professorial mode. She wondered if he missed the academic life.
“The tilt of Earth’s axis varies over…millennia. And like a wobbling toy top the Earth precesses about that axis, also over millennia. And because planetary orbits are ellipses, not circles, the axis of the entire orbit slowly revolves around the sun. In the case of Earth, that last cycle takes more than a hundred millennia. All three processes affect what sunlight strikes the planet, where, and at what angle. All three affect seasons and…climate.”
As she had more or less remembered. “And those processes are independent, correct? Every so often, they peak together.”
“Cycles peaking together have been implicated in triggering ice ages.”
“And extrapolating to Dark? What does our long-range forecast look like?”
He studied his feet. “I don’t know.”
“What would it take to find out?”
“A lot of observing time. And modeling time, too.” He gestured at the image on the big display. “Earth doesn’t have a big neighbor planet like that to tug at it. Or three moons. The cyclic variations here are apt to be more complex.”
Farming and childrearing didn’t leave much time for, well, anything else. Maybe those were the only tasks she was good for.
Something she knew about the history of science had to be useful. Didn’t it?
Maybe this was it.
*
From the deep shadow alongside the reroofed phosphate storehouse, Carlos watched Rikki. Out in the middle of the night, slinking home from Endeavour. Having a bit of after-hours fun, are we?
But kudos for Antonio! Carlos would not have guessed the odd little guy had it in him. Or, more precisely, that he got it into Rikki.
After she slipped past, Carlos continued to his workshop. His extracurricular activities also demanded discretion.
Yawning, exhausted after a full day’s work, he nonetheless toiled in high spirits. For months he had put his free nights into making things for Li. If what she wanted wasn’t candy and flowers, nonetheless each new batch of the gadgets made her very appreciative.
He could appreciate that.
*
Discovery set down on a broad plain, between soaring rock canyon walls.
“Touchdown,” Blake announced. “The crowd goes wild.”
They had landed on a pebbly shore along the Spencer River. A very damp shore, to judge by the steam that billowed around them, blocking Rikki’s view from the cockpit. That fog would dissipate into the dry air long before the ground cooled enough for them to climb down.
“You do realize,” she said, “that I’ve never seen a football game.” Or cared to. Martians didn’t do football: the playing field would have had to be ridiculously big.
“I know many things.” He popped his helmet, unbuckled his safety harness, and twisted around to see her behind his headrest. “Such as that you’ve never asked to accompany me on a routine checkout flight. Not once. Today you announced you were coming and proposed a destination. What gives?”
“Nothing.” Almost nothing, anyway: the vague memory of terrain glimpsed from a fast-moving shuttle, when the two of them had first flown over this region.
“Here in the canyon, we’re out of radio contact. If you have secrets, this is the place to spill them.”
His unhappy expression added, “Unless you’re keeping secrets from me.”
“No secrets,” she dissembled. “I wanted to see these rock faces up close.”
“Be that way.” He turned forward.
“Really, that’s why I came.” And if she saw what she expected to see, she would explain. She just didn’t want to look stupid.
The awkward, silent wait till he popped the canopy release seemed interminable.
Rikki hung a ladder over the cockpit’s side, swung herself up and over, and clambered down the rungs. “I remember when doing that was hard.”
“We’re getting used to the place. Home sweet home.”
Home, sweet or otherwise. That was why she had to get her head wrapped around the climate here. “I’m going to stroll along the river for a ways. Join me?”
“Sure.”
The river’s flow here was slow and placid. When she walked up to the shore and dipped in a fingertip, the water was icy. “No skinny-dipping,” she told him preemptively.
“So what is this about?”
Slowly, she pivoted, taking in the panoramic view. “Isn’t this enough?”
The flat plain stretched for at least a hundred meters behind them before rising to meet rugged cliffs. The river, gray with silt, hugged the canyon’s other wall. Perhaps a half-klick downstream from where they stood, a small but spectacular cascade burst from the nearer rock face to crash into the waters far below. Rikki dubbed the torrent Beagle Falls.
How long ago had this valley silted up? Had the silt accumulated gradually, or had it settled out in the aftermath of some terrible flood? She didn’t know, but an answer to that mystery could wait.
Craning her neck, peering up and up and up, Rikki studied the nearer canyon wall. Two hundred or so meters high. Sedimentary rock. Barren of life, of course, without even a hint of greenery. Great crags and brooding hollows carved as water and wind had patiently eroded the softest rock. Several dozen strata, of varying depths, in countless shades of gray. Subtle, subdued red tones here and there among the grays.
She took out her camera. With its laser rangefinder active to capture precise distances and scales, she started panning.
“Magnificent,” Blake said. “It reminds me of the Grand Canyon.”
“Then my suggestion was worthwhile?”
“You tell me.”
She couldn’t know without detailed analysis, but yes, she was sure. “The layering of the rock embodies sedimentation rates over time. Those reflect the climate.” And cycles of the climate, over perhaps millions of years.
“And that’s important?”
She couldn’t know that yet, either. “It might be.”
*
The inevitable confrontation began after dinner, in an impassioned and arcane outpouring of verbiage from Rikki. Blake, Dana, and Antonio, looking on approvingly, were clearly in on it. And the four had waited till Carlos, Li’s dependable ally (when sober, anyway), had left for his
