Стивен Бакстер - Phase space

Kate said, 'How long?'

Cornelius shrugged. 'The math is chancy. Twenty-four hours at best.'

It feels like half the population of the human race has downloaded. 'Into what?'

Into anything they can find. Some folk are trying to create self-sentient copies of themselves, existing entirely within the data nets. The ultimate bunker, right?

'I thought that is illegal.'

So what do you think the data cops are going to do about it today?

'Anyhow it's futile. A copy wouldn't be you.''

You tell me. There are philosophical principles about the identity of indiscernibles: if a copy really is identical right down to the quantum level, then it has to be the original… Something like that. Anyhow I doubt it's going to be achieved in the time left.

'I'm surprised we aren't running out of capacity.'

There have been a few crashes. But as ends of the world go, this is an odd one, Kate. Even now it's still just a bunch of funny lights in the sky. The sun is shining, the water supply is flowing, the power is on.

And, you know, in a way it's an exciting time; inside here, anyhow. There's a kind of huge technological explosion, more innovation in the last few hours than in a decade.

'I think I should go now. I have people I'm meant to be with, physically I mean -'

Damn right you should go.

'What?'

More room for me, sister.

She felt affronted. 'What use is huddling here? This isn't a nuclear war. It's not even an asteroid strike. Rodent, there might be nothing left - no processors to maintain your electronic nirvana.'

So I'll take my chance. And anyhow there's the possibility of accelerated perception: you know, four subjective hours in the tank for one spent outside. There are rumours the Chinese have got a way to drive that ratio up to infinity - making this final day last forever - hackers are swarming like locusts over the Chinese sites. And that's where I'm headed. Get out of here. There won't be room for everybody.

'Rodent -'

Wake up, wake up.

Kate, with Malenfant and Cornelius, stood on Mike's porch. Inside the house, the baby was crying.

And in the murky Houston sky, new Moons and Earths burst like silent fireworks, glowing blue or red or yellow, each lit by the light of its own out-of-view sun.

There were small Earths, wizened worlds that reminded her of Mars, with huge continents of glowering red rock. But some of them were huge, monster planets drowned in oceans that stretched from pole to pole. The Moons were different too. The smallest were just bare grey rock like Luna, but the largest were almost Earth-like, showing thick air and ice and the glint of ocean. There were even Earths with pairs of Moons, Kate saw, or triplets. One ice-bound Earth was surrounded by a glowing ring system, like Saturn's.

Kate found it hard not to flinch; it was like being under a hail of gaudy cannonballs, as the alternate planets flickered in and out of existence in eerie, precise silence.

It was just seven days since the failed echo from Centauri. 'I wonder what's become of our astronauts,' Malenfant growled. 'Poor bastards.'

'A great primordial collision shaped Earth and Moon,' Cornelius murmured. 'Everything about Earth and Moon - their axial tilt, composition, atmosphere, length of day, even Earth's orbit around the sun - was determined by the impact. But it might have turned out differently. Small, chance changes in the geometry of the collision would have made a large difference in the outcome. Lots of possible realities, budding off from that key, apocalyptic moment…'

Malenfant said, 'So what are we looking at? Computer simulations from the great planetarium?'

'Phase space.' Cornelius seemed coldly excited. 'The phase space of a system is the set of all conceivable states of that system. We're glimpsing phase space.'

Malenfant said, 'Is this what we were being protected from} This - disorderliness?'

'Maybe. As we evolved to awareness we found ourselves in a clean, logical universe, a puzzle box that might have been designed to help us figure out the underlying laws of nature, and so develop our intelligence. But it was always a mystery why the universe should be comprehensible to our small brains at all. Maybe we now know why: the whole thing was a fake, a training ground for our infant species. Now we have crashed the simulator.'

'But,' said Kate, 'we aren't yet ready for the real thing.'

'Evidently not. Perhaps we should have trusted the controllers. They must be technologically superior. Perhaps we should assume they are morally superior also.'

'A little late to think of that now,' Malenfant said bitterly.

No traffic moved on the street. Everybody had gone home, or anyhow found a place to hunker down, until -

Well, until what, Kate? As she had followed this gruesome step-by-step process from the beginning, she had studiously avoided thinking about its eventual outcome: when the wave of unreality, or whatever the hell it was, came washing at last over Earth, over her. It was unimaginable - even more so than her own death. At least after her death she wouldn't know about it; would even that be true after this}

Now there were firebursts in the sky. Human fire.

'Nukes,' Malenfant said softly. 'We're fighting back, by God.

Well, what else is there to do but try? God bless America.'

Saranne snapped, 'Come back in and close the damn door.'

The three of them filed meekly inside. Saranne, clutching her baby, stalked around the house's big living room, pulling curtains, as if that would shut it all out. But Kate didn't blame her; it was an understandable human impulse.

Malenfant threw a light switch. It didn't work.

Mike came in from the kitchen. 'No water, no power.' He shrugged. 'I guess that's it.' He moved around the room, setting candles on tables and the fire hearth; their glow was oddly comforting. The living room was littered with pails of water, cans of food. It was as if they were laying up for a snowstorm, Kate thought.

Malenfant said, 'What about the softscreens?'

Mike said, 'Last time I looked, all there was to see was a loop of the President's last message. The one about playing with your children, not letting them be afraid. Try again if you want.'

Nobody had the heart.

The light that flickered around the edges of the curtains seemed to be growing more gaudy.

'Kind of quiet,' Mike said. 'Without the traffic noise -'

The ground shuddered, like a quake, like a carpet being yanked from under them.

Saranne clutched her baby, laden with its useless immortality, and turned on Cornelius. 'All this from your damn-fool stunt. Why couldn't you leave well enough alone? We were fine as we were, without all this. You had no right - no right…'

'Hush.' Malenfant moved quickly to her, and put an arm around her shuddering shoulders. 'It's okay, honey.' He drew her to the centre of the room and sat with her and the infant on the carpet. He beckoned to the others. 'We should hold onto each other.'

Mike seized on this eagerly. 'Yes. Maybe what you touch stays real - you think?'

They sat in a loose ring. Kate found herself between Malenfant and Saranne. Saranne's hand was moist, Malenfant's as dry as a bone: that astronaut training, she supposed.

'Seven days,' Malenfant said. 'Seven days to unmake the world. Kind of Biblical.'

'A pleasing symmetry,' Cornelius said. His voice cracked.

The candles blew out, all at once. The light beyond the curtains was growing brighter, shifting quickly, slithering like oil.

The baby stopped crying.

'Hold my hand, Malenfant,' Kate whispered.

'It's okay -'

'Just hold my hand.'

She felt a deep, sharp stab of regret. Not just for herself, but for mankind. She couldn't believe this was the end of humanity: you wouldn't exterminate the occupants of a zoo as punishment for poking a hole in the fence.