“So be it.”

“It might kill all of us.”

“I know. I can send you back if you want.” She gestured at the box of her teletrasporta, there between them on the floor of the cabin.

“Not yet.”

On the window screen he could see that other ships were also rising over the now ruddy curve of Europa, silver pips surrounding them above and below. Hera spoke at speed to her unseen interlocutors. He saw a new crater wall that looked as though it were blanketed by diamond dust; this was where Ganymede’s ship had crash-landed, presumably. All the ships were staying well away from the hole, which still spewed a faint talcum into space—not at speed, as with the sulphur geysers of Io, but as if the planet were breathing out frost on a cold morning. Hopefully it was not its last breath.

Galileo was thrown forward against his restraints by an abrupt deceleration. Their viewscreen showed that they had been docked by another ship so alike in appearance that it seemed to be the image of theirs in a mirror. Hera was both talking and tapping at her pad. Galileo felt or heard the antechamber doors opening and shutting. The other ship pulled away.

“To Jupiter,” Hera said.

A sharp acceleration up. On the screen Jupiter lay ahead of them, spotted like a pox victim. Poor young Ferdinando had looked like that in 1626. The rest of their little fleet was nowhere to be seen. After a period of silent flight, heading up to the hectic sphere, now more awesome than ever, Galileo said, “Can you give me the tutorial that tells me what happened between my time and yours? Something compressed? Because I think I need to know.”

“Yes.” She handed him her celatone. “It will go fast. It will be a sum over histories, as it is called, showing you many potentialities at once, in the braided stream format. It will all come on you in a synaptic bloom. Those can be confusing, and give you a headache.”

Galileo put the heavy helmet on his skull. Marina’s face—the old dragon—a ball falling through space in a swift curve—

Then there it was. Voices speaking in Latin overlapped in his head, as if several Plutarchs spoke at the same time, but mostly it was an instantaneous flood of images. Galileo was on the Earth and even in it. He was everywhere. He looked, he listened, but more than anything else he felt the ferocious tempests in Europe after his time, felt how the early advances in math and physics that he had learned from Aurora, so beautiful and inspiring, were somehow intertwined and complicit with a continuous tale of war and spoilation. It didn’t have to be that way, and there were fragile strands in which it seemed not to have happened, but the main broad channel of history was filled with blood. Humanity’s increasing power over nature meant more powerful weapons, of course, along with more powerful medicines. Populations bloomed, the whole world was explored and settled, the primitive peoples killed off, those less primitive enslaved or conquered and turned into client states of the European powers. Even Italy coalesced into a single state, as Machiavelli had so much desired, although late in the imperial moment and at a point where their only colony was poor Abyssinia. But none of that mattered. All over the world, newly growing populations were at each others’ throats—fighting, killing, dying. In the nineteenth and twentieth centuries, the world was carved up entirely into industrial empires; people were enslaved in factories and cities. Galileo felt their lives: not one in ten of them even tended a garden. “They live like ants,” he groaned.

In the next period, the wars between empires grew massive—every part of civilization so mechanized, cruel, and powerful, that a point came where entire nations of people were gathered up and fed into roaring furnaces and destroyed. Billions died. Sickened, appalled, Galileo watched on with a shrunken heart as all nature was then in effect fed to the furnaces to feed a rapacious humanity that quickly rebounded from the deaths and became superabundant again, like an infestation of maggots, a sporulating mass of suffering beasts. In such conditions, war and pestilence were constant, no matter the progress in mathematics and technology. Total war was more the rule than the exception; army against army was rare. Marking all the potentialities and mocking all their potential, innumerable natural and human catastrophes broke out all across the time streams, until in Galileo’s mind the Earth appeared not unlike the maelstrom-strewn face of Jupiter, a planet red with blood. It came to the point where it was an open question how much of humanity could survive—and all this in a supposedly scientific world, with continual advances in their technologies and their potential physical control over nature. It was horrifying to witness, as if a race between creation and destruction had both sides succeeding at once and accelerating all the while, creating in their conjunction something unexpected and monstrous.

Galileo moaned as he experienced all this, as it blossomed all at once and entire in his memory, something he always seemed to have known. The inherent anger, the depth of hatred, the potential for evil; he had always known, always seen it. At any point the monsters could break out. Again he saw that he was being shown not just one single history but a superposition of many of them, following the same metapattern but all collapsing into chaos to one degree or another, so that he was being flooded with many bad potentialities at once. Some were bad, others were horrific, a few were stark apocalyptic.

He saw further, saw then that the centuries after those were always a miserable desperate struggle, in which a much reduced and demoralized humanity tried to get by in the wreckage of the world. Having ruined so much, being so many fewer, and yet also becoming quickly more powerful, also more chastened and realistic, people began patching things up. Some recoveries went better than others. Nature itself was robust, and its harrowed surviving forms proliferated as always. For humanity, it was slower and less steady. So much had been lost; Galileo felt in his stomach the iron ball of despair that had dragged down every single version of these generations’ efforts. Shattered, traumatized, frightened, they did what they could. Science itself proved as robust as any other living survivor, as tough as some jungle vine spreading through the tropics. A new paradigm, born of exhaustion as much as hope, led them into an array of emergency landscape restorations. Centuries of various duration told of a dogged and heroic effort to rebuild some minimal scaffolding for the future. It was all done for the future. A human civilization that was now aware of the dangers that the extinction of any species posed for all of them did what it could to restore the natural fauna and flora of the Earth, and the underlying chemistry of the ocean and air, so badly poisoned. Here they were aided by the fecundity of life, its resilience; and in this era science finally was directed entirely at the problem of restitution, and put foremost in humanity’s judgment of its efforts. Now it seemed that there was a strong channel in these braiding streams that ran clear toward something healthy. In these worlds some of the huge menagerie of extinct species were returned, reconstituted or engineered from what germs and seeds remained of them.

After that he saw the slow restoration of Earth, and even sometimes the return of humans to space. They had been there briefly before, in the midst of the wars, when it had meant little or nothing; now their launch into the solar system was a burst toward fresh starts, as all kinds of groups went out to start anew on Mars, in the asteroids, around Jupiter and Saturn and Mercury. This was their Accelerando, bursting away from Earth like a seedpod—people and potentialities everywhere expanding outward in what looked like Fibonacci spirals.