“You got it.” Venus produced a flask from the low shelf unit beside her workstation. “You want some coffee?”
“I’m honored.”
Venus poured out two cups.
Holle sipped gratefully. The ability of the processing systems to keep producing a hot, warm liquid that still tasted something like actual coffee nearly eight years after launch from Gunnison was one of the Ark’s minor miracles. “You always seem to have the best brew in here, Venus.”
Venus smiled, her face dimly illuminated by her glowing screen. “Got to give people some kind of incentive to visit. By the way, when that hatch is locked the data feed to the rest of the ship is cut too. So we have a little privacy.”
Holle stared. “You cut yourself off even from Wilson?”
“Oh, our great leader gets a continuous feed.” She winked at Holle.
“Which isn’t to say he’s fed the unvarnished truth the whole time.”
“You manipulate the data feed?”
“Wilson needs us, he needs what we do. As long as I’m no direct threat to him, I think he lets me keep my little secrets.”
And there was an expression of the most basic tactic for survival on this Ark: to grab a bit of power and hold on to it.
“So you have a ‘little secret’ today?”
Venus nodded. “I’ll tell Wilson about it when I’m ready. We need more data to establish the case. But-”
“You said there’s a problem.”
“With Earth II,” Venus said. “I think there’s a problem with our destination, Holle. I need you to help me figure out how to handle it.”
“Shit.”
Venus grinned. “That doesn’t begin to cover it.” She swiveled a screen so it faced Holle. “We have images of Earth II. Still rudimentary, but-”
Holle was astonished. “Wow. Images. And you kept them to yourself?”
“So far.”
“Suddenly I feel like Columbus.”
“More like the crew of Apollo 8,” Venus said. “Remember how Gordo used to claim to have met them all, Borman, Lovell and Anders? The first to leave Earth orbit, the first to see the world whole and complete…” Her finger hovered over a key. “Let me show you how we got the data.”
Since going to warp, Venus and her team had continued to use the Ark as a mobile telescopic platform for inspecting the nearby stars and their planets, extending the depth and quality of the searches that had been possible from Earth, and from the Ark itself at Jupiter. It seemed remarkable to Holle that it was possible to perform such fine work from within a warp bubble, with the telescopes peering out through a wall of folded spacetime. But the lensing of the light was easy to unravel; you just traced the rays back along the paths they had followed, following solutions through the forest of relativistic equations that described the Alcubierre warp.
Even now that they were out among the stars, the feeble light of a planet, reflecting a scrap of its parent star’s radiation output, remained difficult to detect. So Venus had her telescopes look for the subtle dips in a star’s light when a planet transited before its face-a technique that would only work if the orbit happened to be edge-on to the Ark. Or she looked for the wobbles in a star’s motion characteristic of it being pulled around by the orbiting bulk of planets. What struck Holle as the cleverest technique involved a pair of telescopes observing the same star but from some distance apart. Light acted as a wave, and waves when combined interfered with each other, constructively or destructively. The signals from the two telescopes were combined so that a destructive resonance occurred between the two feeds of the star’s own light-and with the star itself made invisible, any planets, each no brighter than a billionth or so of the star’s own luminosity, could be made out.
With such techniques a planet could be observed closely, its mass and gravity estimated, the spectrum of its light analyzed for signs of water and for such atmospheric constituents as methane and oxygen. Before the Ark left Jupiter these Earthlike signatures had been recognized of a planet of 82 Eridani, a star not unlike the sun.
“But,” Venus said, “we’re not just staring at Earth II the whole time. We’ve been looking further out, as far as we can see, across a sphere a hundred light-years in radius, trying to map everything we can. Why not? Even if we make it to Earth II it’s going to be a long time before anybody else gets a chance to do any planet-spotting, and certainly not from a platform like this. There are limits to detectability, a base of astrophysical noise you can’t see through. But we’re easily sensitive enough to spot an Earthlike planet at an Earthlike distance from a sun-like star, for instance from stellar velocity oscillations of a centimeter a second or so. So we’re drawing up a catalog, a legacy for future generations.” She grinned, and the Venus that Holle had grown up with peeked out from inside the grave thirty-year-old woman. “Besides, what else have we got to do all day? It’s this or scrub the walls.”
“I believe you.”
“So you ready for Earth II?”
“Hit me.”
The screen before Holle lit up with a disc, a world. It was almost full, with only a crescent in shadow, to the left-hand side. And the lit portion, the right hemisphere, bathed in the sunlike light of 82 Eridani, was dominated by a shield of ocean that gleamed gray. Holle saw a dazzling highlight at the right-hand limb cast by the out-of-sight star. There was a swirl of cloud in that daylight hemisphere, a big storm system of some kind. Elsewhere she saw land, a thin gray belt across the waist of the planet, another landmass below it, a kind of archipelago above. The image was blurred, an artifact of the telescopy; no details much smaller than continents were visible.
Venus watched her, grinning. “Even Wilson hasn’t seen this yet.” Holle shook her head. “It’s like a special effect in a HeadSpace game. And so Earthlike. No polar caps?”
“No, though the surface temperature isn’t much different from Earth’s. Well, there have been intervals in prehistory when Earth was ice-free.”
“Are these true colors? The landmasses are a little darker than on Earth maybe.”
Venus nodded. “True. Not so green as Earth. 82 Eridani is a G5 class rather than a G2 like Sol, and the light is subtly different. We suspect there’s some different light-gathering chemistry going on down there.”
“But there’s life.”
“Oh, yes, we think so. No chance of that oxygen-nitrogen atmosphere without it.”
Holle peered at the scattered landmasses. Would the shapes of these strange continents become as familiar to the Ark’s children as Africa and America and Asia had once been to her own parents and grandparents, before the flood covered them over? “Venus, this looks pretty good to me. What’s the problem?”
“Watch this sequence. Earth II’s day is longer than Earth’s, about thirty hours. These images were taken a couple of hours apart.”
It was like a crude, blurry animation, showing the world turning on a horizontal axis. That long central landmass moved downwards, and the other continent moved out of sight, under the belly of the world. The belt of shadow didn’t shift. The sun was out of sight, somewhere to her right…
Suddenly Holle saw it. “Oh. It’s a Uranus. The axis is tipped over, pointing at the sun.”
“Tipped through almost ninety degrees. Compared to, what, twenty-three and a half degrees for Earth? Actually we think it’s more like Mars, where the axis swings back and forth over periods of hundreds of thousands of years. Earth is stabilized by the moon; Mars lacks a big enough moon-and so does Earth II. The tipping seems to be tied into tidal effects from two big Jovians further out.”
“That’s why there’s no ice.”
“Yes. Each pole must be blasted by continual sunlight for half the year, while the other is in permanent shadow.”
“How could this come about?”
“Planets, and planetary systems, are common, Holle. We’ve learned that much-the sky is full of them. But the formation processes they go through are chaotic. They coalesce out of clouds of dust and ice, and then endure a hierarchy of impacts, from dust grains banging into each other up to the point where planet-sized masses collide. Not only that, there’s migration. Stars are born in crowded nurseries, and the remnant cloud is blown away pretty quickly by the light from neighboring baby stars. But before then tidal friction with the cloud can cause
