“So, a Galaxy,” Malenfant said. “Our Galaxy?”

“I think so,” Cornelius said. “Four spiral arms… It matches radio maps I’ve seen. I’d say our viewpoint is a quarter of a galactic diameter away from the plane of the disc. Which is to say, maybe twenty-five thousand light-years away. Our sun is in one of the spiral arms, about a quarter of the way from the center.”

“How did we get here?”

“I’d guess that Cruithne evaporated out of the Solar System.”

“Evaporated?”

“It suffered a slingshot encounter, probably with Jupiter, that hurled it out of the system. Happens all the time. If it left at solar escape velocity, which is around a three-thousandth of light speed—”

Emma worked it out first. “Seventy-five million years,” she said, wondering. “We’re looking at images from seventy-five million years into the future. That’s how long it took that damn asteroid to wander out there.”

Cornelius said, “Of course if that isn ‘tow Galaxy, then all bets are off…”

Seventy-five million years was a long time. Seventy-five million years ago on Earth, the dinosaurs were dominant. Emma’s ancestors were timid mammals the size of rats and shrews, cowed by the great reptiles. Look at us now, she thought. And in another seventy-five million years, what will we have achieved?

Cornelius’ voice was tense, his manner electric. He’s waited all his life for this, Emma realized, this glimpse of the far future through an alien window.

“This opportunity is unprecedented,” Cornelius said. “I’m no expert on cosmology, the future of the Galaxy. Later we have to consult people who can interpret this for us. There is probably an entire conference to be had on that Galaxy image alone. For now I have some expert systems. I can isolate them, keep them secure—”

Emma said, “What did she mean, reef?” “I think she meant the Galaxy. The Galaxy has, umm, an ecology. Like a coral reef, or a forest.” He looked up. “You can make out the halo, the spherical cloud around the main disc: very ancient, stable stars. And the Population II stars in the core are old too. They formed early in the Galaxy’s history: the survivors are very ancient, late in their evolution.

“Most of the star formation going on now is happening in the spiral arms. The stars condense out of the interstellar medium, which is a rich, complex mix of gas and dust clouds.” Checking with his softscreen, he pointed to the spiral arms. “See those blisters? The e-systems are telling me they are bubbles of hot plasma, hundreds of light-years across, scraped out by supernova explosions. The supernova shock waves enrich the medium with heavy molecules — carbon, oxygen, iron — manufactured inside the stars, and each one kicks off another wave of star formation.” “Which in turn creates a few new giant stars, a few more supernovae—”

“Which stirs up the medium and creates more stars, at a controlled rate. So it goes: a feedback loop, with supernova explosions as the catalyst. The Galaxy is a self-regulating system of a hundred billion stars, the largest organized system we know of, generations of stars ending in cooling dwarfs or black holes. The spirals are actually waves of stellar formation lit up by their shortest-lived, brightest stars — waves propagating around the Galaxy in a way we don’t understand.”

“Like a reef, then,” Emma said. “The Sheena was right.”

Cornelius was frowning at his softscreen. “But…”

“What’s wrong?”

“There’s something not right. I — the e-systems — don’t think there are enough supernovae. In our time the hot plasma bubbles should make up around seventy percent of the interstellar medium… That looks a lot less than seventy percent to me. I can run an algorithm to check—”

“What,” Malenfant said evenly, “could be reducing the number of supernovae?”

Cornelius was grinning at him.

Emma looked from one to the other. “What is it? I don’t understand.”

“Life,” Malenfant said. “Life, Emma.” He punched the air. “I knew it. We made it, Emma. That’s what the supernova numbers are telling us. We made it through the Carter catastrophe, got off the Earth, covered the Galaxy.”

“And,” Cornelius said, “we’ve started farming the stars. Remarkable. Mind has spread across the stars. And just as we are already managing the evolution of life on Earth, so in this future time we will manage the greater evolution of the Galaxy. Like a giant life-support system. Closed loops, on a galactic scale…”

Malenfant growled. “I got to have this visual next time I give a speech in Delaware.”

“If this is intelligence,” Emma said, “how do you know it’s human?”

“What else could it be?”

“He is right,” Cornelius said. “We seem to be surrounded by a great emptiness. The nearest handful of sunlike stars shows no signs of civilization-produced radio emissions. The Solar System appears to be primordial in the sense that it shows no signs of the great engineering projects we can already envisage: for example, Venus and Mars have not been terraformed. The face of the Moon appears to have been essentially untouched since the end of the great bombardment four billion years ago.

“Even if They are long gone, surely we should see Their mighty ruins, all around us. But we don’t. Like an ant crawling around a Los Angeles swimming pool, we might have no idea what Their great structures are for, but we would surely recognize them as artificial.”

Malenfant said, “Today, there’s just us; in the future, somebody spreads across the Galaxy. Who else but us? Anyhow seventy-five megayears is more than you need to cover the Galaxy. You know, we should look farther out. Another few megayears for the biosphere to reach Andromeda, three million light-years away—”

Cornelius said, “The nearest large Galaxy cluster is the Virgo Cluster. Sixty million light-years out. It’s plausible the biosphere might have reached that far by now.”

“We have to look,” Malenfant said. “Send through more fireflies. Maybe we could establish a science station there, on the future Cruithne.”

“Christ, Malenfant,” Emma said. “It’s a one-way trip.”

“Yeah, but there are resources on Cruithne, just as there are

now. Enough to sustain a colony for centuries. We’d have no

shortage of volunteers. For half a buck I’d go myself. Maybe we

could contact the downstreamers directly.”

Malenfant and Cornelius talked on, excited, speculating.

But they are missing the point, Emma thought. Why are we

being shown this? What do the downstreamers wanft

There was a blur of movement in the corner of the softscreen image. It was out of focus, a flash of golden fabric.

“There’s the Sheena,” Emma snapped. “Cornelius, the camera. Fast.”

Cornelius, startled, complied. Again the agonizing wait as Cornelius’ command crept across space, through the portal, to this startling future.

The picture tipped up drunkenly, and Galaxy light smeared across the image. But they could see that the beach ball was rolling across the surface toward the portal.

Emma said, “She’s going to come back through.”

“You don’t understand,” Cornelius said tightly. “She won’t

come back anywhere. The portal isn’t two-way.”

“So if she steps through it, she will go—”

“Somewhere else.”

On the screen, the golden beach ball sailed into the interface — reddening, slowing, disappearing.

The firefly rolled forward, through soft Galaxy light, toward

the downstreamer gateway.

Maura Della:

Open journal. October 22,2011.

Can it be true? Can it possibly? Do we want it to be true?

People seem to think I have a more privileged access to Malenfant and his projects than is the reality. I can’t tell whether those now-famous downstream images are a hoax, or a misinterpretation, or if they are real. I can’t tell if they represent the only future available to us, or one of a range of possibilities.