One of the underappreciated thrills of reading science fiction is the possibility, however unlikely, that some far-out fiction will eventually prove to be at least partial fact—its wild speculation maturing over time until, like fine wine forgotten in a cellar, it is finally remembered and savored. Sometimes reality’s similarity to an author’s imaginings can be downright eerie such as H. G. Wells’s vision of nuclear war from 1914’s The World Set Free or Jules Verne’s From the Earth to the Moon, which in 1865 predicted many key features of the Apollo 11 lunar landing. In Verne’s book and in actual space history three astronauts launched to the moon from Florida and returned by splashing down in the Pacific Ocean, all in a cramped capsule named for Columbus.

Despite outward similarities, however, reality never seems to truly repeat these imaginary histories—instead, it merely rhymes. Wells’s nuclear bombs were very different from the ones eventually built, although the physicist Leo Szilard did read the book about a year before conceiving of the nuclear chain reactions that made real atomic weaponry possible. Similarly, the fact that the Apollo 11 command module was named “Columbia” was not coincidence—it was directly inspired by Verne’s capsule, called Columbiad, which was shot from a giant cannon in Tampa rather than a rocket launchpad in Cape Canaveral. In such self-fulfilling prophecies dreams become reality as other people, inspired by an author’s visionary extrapolations, seek to confirm or refute them.

More recently, the most obvious example of real and fictional history aligning is last month’s announcement of Proxima b, a newly discovered and potentially Earth-like planet orbiting Proxima Centauri, our solar system’s nearest neighboring star. Astronomers presently know little more than the planet’s estimated mass—perhaps just a third greater than Earth’s—and its orbital distance from its star, which is slightly more than seven million kilometers. Additionally, they suspect it might be tidally locked, meaning the world eternally turns the same face to its star, leaving its trailing hemisphere forever shrouded in night. As meager as they are, these observations hew close to ones that first appeared in 2013 work of fiction, the novel Proxima by the author Stephen Baxter—a book that describes the human exploration and colonization of a remarkably similar world around Proxima Centauri centuries from now. Baxter’s planet is tidally locked and six million kilometers from its star and weighs in at just 8 percent lighter than Earth rather than 30 percent heavier.

Proxima b’s chief discoverer, the astronomer Guillem Anglada-Escude, has called the resemblance “uncanny.” Indeed, the biggest difference between the imagined and actual planet may be in name—Baxter called his “Per Ardua” (Latin for “through struggle”) instead of the less-poetic “Proxima b.” Both real and fictional planets lie in Proxima’s habitable zone, the temperate circumstellar region in which liquid water could exist. Inspired by scientific papers reviewing the plausibility of tidally locked planets, Baxter imbued his with breathable air, oceans of water and a complex climate and biosphere sculpted by the world’s tidally locked state and the flaring outbursts of its nearby star. For now astronomers can only dream of giant telescopes or interstellar spacecraft that could investigate the real planet for such signs of habitability and life. But those signs could be there nonetheless, just waiting to be found. Or, of course, the planet could be utterly uninhabitable. Hopefully a mixture of science and speculation will soon drive researchers to find out. Until then, an optimistic-but-plausible peek at just what Proxima b might look like can be found in the following excerpt from Baxter’s book, detailing the journey of a group of scientists (along with a hardy robotic “ColU” or “colonization unit”) as they travel from the world’s sunlit face to its dark side.

From Proxima, by Stephen Baxter. Copyright © 2013, Gollancz.

On they traveled. Day after day passed, marked only by a human sleep cycle still slaved to light-years-distant Earth—that and the slow descent of Proxima in the sky, toward the northwest horizon, away from the zenith it occupied as seen from the substellar Hub. The shadows that preceded their two vehicles grew steadily longer, and as the dwarf star’s light struggled through thicker layers of air it frequently looked reddened, Proxima’s spitting flares and mottling of spots more easily visible to the naked eye. The air grew colder too; soon they couldn’t leave the rover’s heated interior without extra layers of clothing.

After more than forty days they reached a belt of rim forest.

Here they rested a day to stretch their legs and explore, while the ColU set out along the edge of the forest to seek a way through. Neither Liu nor Stef had seen such a forest before, and they wandered, wide-eyed, through its dimly lit, cathedral-like spaces, the slim stem trunks reaching up to those broad, patient triple leaves above. And they marveled at the immense kites of the canopy, and the ferocious scavengers competing for the slightest fall of nutrient into the almost aquatic gloom of the forest floor. For Yuri, all this brought back memories of his earliest days on Per Ardua, when he had explored the forest of the northern reaches, so similar to this place, with the likes of John Synge and Harry Thorne and Pearl Hanks and Abbey Brandenstein, all long dead.

The ColU returned with news of a break in the band of forest, at a broad valley not far south of here. They returned to the rover and set off that way. The valley proved to be the relic of a glaciation, with a wide floor and steep walls. A river running from distant hills, substantial in itself, was dwarfed by the ice-cut valley across whose floor it meandered.

They followed the cut through the forest band, which proved to be quite narrow; soon it thinned out, leaving only isolated stands of trees.

In the more open landscape beyond the forest the driving was easy, along the gravel beds that lined the banks of the glacial valley. There were stem beds here, and kites flying, big, slow, ungainly beasts of a kind Yuri hadn’t seen before, and builders, slowly working on their middens and nursery bowers. The scene was bathed in the dim light of a lowering Proxima, with the faces of hills up ahead washed with a pinkish glow. Life here seemed sparse, tentative, starved as it was of energy. Yuri remembered in contrast the tremendous vegetable vigor of the Hub jungle at the substellar point.

The valley steadily narrowed as they worked their way upstream, toward a range of hills that were soon no longer so distant. The river’s source turned out to be a corrie, a huge scoop high up in a glaciated hillside.

Long before they reached that point Stef guided the rover away from the river and toward a pass through the hills, and beyond the pass they descended onto a plain. The shadows of the hills behind them now stretched far ahead, but they could see more ranges of hills marching off into the distance, with ice-coated peaks that gleamed in the dimming Proxima light and glaciers striping their flanks.

As they crossed the plain the ColU requested more stops. It took samples of the life forms it found in pools of permanent shadow, mostly slow-growing lichens in frosty patches feeding off a trickle of reflected light, protected from any motile scavengers by the very darkness that cradled them.

Once the ColU, digging, found what it called a rare, ancient fossil bed, saved from volcanic obliteration by some accident of uplift, which contained traces of creatures like builders but much taller, each with three long multijointed stem legs. These were creatures built for migration, for speed, the ColU argued. Perhaps these were relics of a transitional age, while the planet’s spin was slowing, but before it became fully locked in its synchronized day-orbit cycle. In such times, the ColU speculated, there must have been creatures that had migrated continually, keeping up with the slow passage of Proxima across the sky. Perhaps these ancestral builders had been among that  throng. They discussed this, made some records, moved away.

They drove on, and on.

•   •   •

Close to the fiftieth-day halfway mark, Proxima touched the horizon at last. Now, Yuri knew, they would descend into the shadow of the planet itself.

In the days that followed Proxima descended with agonizing slowness, its light ever more twilight red, its apparent shape distorted to obliquity by layers of the cool air, its lower rim sliced off by the horizon. Still there were a few stands of trees, an occasional kite flapping. But life here was dominated by the stromatolites. Some of them, huge, were oddly cup-shaped, their surfaces shaped like bowls to collect the  drizzle of photons from the setting  sun. Liu said they looked like natural radio antennae.

They didn’t get to see Proxima set fully. Before that point they drove into weather, seemingly unending storms, rain showers, fog banks, even snow blizzards. Stef argued that as the warm air of the starlit side spilled over into the cool of the dark side, it must dump all its water vapor as clouds and precipitation. The whole terminator, right around the planet, must be a band of semipermanent snow and rain and fog, and they saw no more of the sky for a while. But they did see streams, rivers, some ice-flecked, flowing down the cloud-shrouded flanks of hills and uplands: the water delivered by the air from the dayside, flowing back the way it had come. Thus, Stef observed, cycles of energy and mass would be closed, all around the terminator, the dividing line between night and day.

When they passed through the weather band and the sky cleared at last, the view was spectacular. Now they rolled through a sea of shadow that pooled at the feet of hills whose upper slopes were still in the light, shining above. Trees clung to these islands of illumination in the sky, with huge kites flapping lazily. Even farther down the slopes life prospered, a secondary kind, pale, starved-looking creatures a little like crabs or segmented worms, all stem-based, which seemed to feed solely on the fall of dead leaves and other detritus from the higher ground.

Yuri felt stiff from the traveling, eyes rheumy, perpetually tired. Yet he was discovering wonders. “This stuff is wasted on three old fogies like us.”

The ColU asked for an extended halt. “Those summits are effectively islands. There could be unique biota up there, at least among the non-flyers, even the tree species. A whole array of unique ecosystems, in starlight islands all around the terminator.”

“To be explored by somebody else,” said Yuri gently. “We’ve got our own goals to achieve. Come on, ColU. I hoped you tested out your floodlights . . .”

So they went on, rushing past marvel after marvel.

They lost Proxima’s direct light at last. Now, under the cloudy skies that persisted near this terminator line, the only glow came from the pools of light cast by their own floods, and the rover’s brightly lit interior was a refuge from the dark.

Stef and the ColU both kept a careful watch on the temperature outside; it was dropping, of course, but not dramatically quickly. Under thicker cloud it could even rise above freezing. “Thus proving the theory,” said Stef, “that a thick atmosphere on a world like this is enough of a thermal blanket to transport sufficient heat around to the dark side to keep everything from freezing up.”

“That and the fact that all the air didn’t freeze up in great bergs of solid oxygen and nitrogen on the far side a billon years ago,” Liu said dryly. “That and the fact that we are still breathing.”

“But it’s always good to have observational confirmation.”

As they pushed on, the cloud cover broke up, quite abruptly, to reveal a star-crowded sky. The temperature plummeted, and frost gathered.

During one rest stop Yuri bundled himself up in thermal underwear and padded coat and over-trousers, and went out with the others to look at the sky.

“Funny thing,” he said. “I’ve never seen much of the stars, one way or another. When I was a kid, before the cryo, the night sky of Earth was a washout. Full of space mirrors and other orbital clutter, even away from the glow of city lights and the smog. You could see the stars from Mars, but we weren’t let out of the domes. And then, here on Per Ardua, the sun never sets at all.”

“Drink it in, my friend,” Liu said. “Drink it in. You can’t beat the Alpha suns, can you?” A dazzling pair of diamonds, their light bright enough to cast shadows—bright enough, the ColU thought, to power some feeble photosynthesis.

Stef, meanwhile, was staring east. “Look. Can you see that?” It was a brilliant star, hanging low on the horizon.

“I see it,” murmured the ColU. “But a star of that magnitude does not feature in the constellation maps I have stored in my memory. A nova, perhaps?”

“We’d have heard of that,” Stef said. “I guess we’ll find
out . . .”