In all its capacity, time and space can masquerade as each other, but most of the time I think it's a trick. A pavane. A three-card monte. I've probably always thought that.

"Always" for us being, we think, about 88 billion Earth Prime years. And here we are approximately, 86.9 billion light-years away from Earth Prime. We think. The dot in space-time of our departure is so distant it defies measurement

or memory.

But this... very candidate planet... I can almost believe it's where we started. It's present. As present as Campbelline was here with me, for periods of 18 months to 3 million years, at 45 times in our history. We've paired and unpaired, nearly hated and also loved.

Infinite possibility doesn't really always mean infinite truth. Richie, for example, I went with and talked only once, two billion years in. One time, too many altogether.

Inside this ship, space is definitely finite indeed.

"It's definitely a Goldilocks planet," says Campbelline, floating to my side to look at the navigation display,

so to speak.

"A good thing too," I say. "We're low on copper, oxygen, and salt, and we need to rebuild the cargo wing again."

There are, or should be, 11 other ships looking for Earths, each with a starting crew of 100 cyborn humans. Rebuilding their ships, and rebuilding themselves, ad infinitum. They should each be in a different Hubble volume by now, each beyond the universe that once was known. I bet most settled for close-enough planets long ago, or died – radiation through a crack, starvation in an

empty space.

But we've stuck to our orders: Find Earth. Fix it.

There must be another Earth, or so the theory goes, if the universe carries on much the same in all directions. If we find an Earth at an early enough stage, we'll travel backwards in history as we've travelled forward in time, onward in space. We can give our one Earth at least a chance.

And will that matter, in the grand dance? If it doesn't matter to get Earth right, Campbelline said once, and then nothing matters. Yes, I said, and adored her, or was it the other way around? That was our 32nd meet up to be precise and we were entering Andromeda.

As we watch this blue planet on the navigation display, I don't say the words. I make her say them instead. Out of – what? Boredom, perhaps. A million monkeys with typewriters, we are, only there are 34 of us and none of us know how to type. We remember the concept of typing. We cyborn remember a lot, although we replace our brains every few decades like the rest of our bodies. Tissue printed with memories encoded, albeit in a lossy medium. A ship of Theseus, piloted by humans of Theseus. The Argobots, Jamil calls us. He makes the joke every millennium and we all laugh like it's the first time.

We can't remember everything, not 83 billion years, but we remember more than a human brain should. Things that happened eons ago, to us, sometimes lodge in a groove in our reprinted brains and remain, lacking context. We have to treat most of them as if they were dreams, or else we get very angry. That's what happened to Gil, who died a galaxy ago in rage. We lose people, sometimes. We started out with 100.

What would I do if I lost Campbelline forever? I can't say; that hasn't happened yet. In an infinite universe the only thing I know for sure is that it will.

"It's blue, Damsel," Campbelline says at last, her tone chastising me for being difficult. "The planet is blue. In a solar system….."

"The 4,872th blue planet we've seen in this Hubble volume. That doesn't mean that it's

an Earth."

"OKAY, Damsel."

"Let's just check it out, then, all right?" calls Richie from the exercise bay. As if we were going to do anything else.

We do remember Earth, all of us. That memory is hard-coded.

I try to remember what Campbelline looked like, originally. Not much different, if you blur the line where her ear was attached last month. We're organic, mostly; our ever-replacing parts built to function without much gravity or sunlight. Synthetic and very organic. We can be one or the other, according to mood.

We turn, we tumble, and we take our places in petty dramas for no audience whatsoever.

Lonely though we are, we have not spoken to the beings whose non-Earth planets we plunder. So many of them: some very like humans, and some very unlike. So tempting but we have our orders. We're looking for home. We're going to get it right. If we broke a habit – a raison d'etre – of 88 billion years, would that break us? We don't ask the question aloud. We just keep going.

In the second Hubble volume, some things seemed familiar – some nebulas and stars – but we couldn't be sure. We couldn't put names to anything.

In H3, we're seeing more that we recognise. The particles have arranged themselves in tantalising ways. But we know the nearest doppelganger universe could still be very distant indeed.

We get lucky, as all gamblers do eventually. As we approach candidate planet H3-4872, we see familiar continents, for the first time. We know it's the first time: the ship records our observations, but even so, it isn't something we'd forget. We stop watching the navigation display and crowd the cupola, jostling for a view. All 34 of us. We now know each other’s eating and sleeping habits like our own.

The Himalayas curve oddly, and there are smaller differences. But it's heart stoppingly close. No space debris, no signals. They don't know we're here.

Jamil is a meteor, his capsule landing in the Gobi desert. Six weeks later he returns, a rocket in the night.

"About 1675 Common Era," says Jamil, excited. "The civilisations are very similar. Japan has a Shogun and the Ming dynasty didn't hang on. I can't give you a delta without a global study. At a guess, we're looking at five percent off. It's pretty close."

Campbelline turns to me, because I've been the captain since Gil died, although most of the time, it doesn't matter. We carry on with the matters as we always have. "Damsel, it's your call. We can infiltrate. We have 350 years to try to warn them."

I nod, slowly. In 350 years, this Earth will reach the point of no return, where cascading disasters will consume humanity within a space of the next four centuries. Long enough to build a dozen spaceships of Theseus, but no longer.

In 1675, this Earth still has time to turn it around. But look at those Himalayas.

I don't need Jamil to give me a delta to know that this isn't home.

"It's a blip, really, 350 years," I say. "Afterwards, we can keep moving; and then keep looking for the real thing."

I turn to Campbelline and smile, but her eyes are pained. Right now Campbelline can't allow forever to be so brutally distant. I know that look. I mean, I've been there.

I do what she always does for me. I put my arm around her, as if this were our only chance to be together.