Stephen Baxter: Last and First Contacts

A band of light cut across the cloudy disc that spanned the sky. I saw sparks: huge stars, forming, blazing and dying. Millions of years passed with each heartbeat.

‘We’re sitting in the disc of one galaxy,’ Elstead murmured, ‘as it intersects the disc of another. The loose gas in both galaxies is being compressed to form new stars – it’s the greatest star-birthing event in either galaxy’s history. Tough on any life forms around, however.’

The stars around us swam, agitated, like bees pitched out of a hive. Only Sol burned firm, reddish, immovable; perhaps we orbited it. The delicate structure of Andromeda, only just discernible as a spiral, began to break up. What looked like gas fountained outwards, away from me, multi-coloured – but that ‘gas’, brilliantly lit, was made up of stars, clouds and streamers of stars. But the streamers quickly dispersed.

‘Show’s already over,’ Elstead said. ‘For a while the collision has created a brilliant, elaborate hybrid. But it is quickly settling down into a huge composite galaxy, a plain elliptical, with the delicate spiral structures of the originals broken up. And most of the star-making gases used up too. An expensive firework display.’

It could have been a simulation. I had sat through much more elaborate VR adventures than this. But still … ‘Elstead, when is this collision due to happen?’

‘Round numbers?’

‘Just tell me.’

‘Three billion years after our time.’

I looked for the sun, the one constant in the firmament. But its colour had changed, becoming fiery, and I thought I saw a disc. ‘Is something wrong with the sun?’

‘Walter, I thought the red giant phase wasn’t due until six billion years?’

Junge checked figures, and shrugged. ‘The astrophysicists could only give us predictions. Maybe the galactic collision disrupted solar physics, somehow.’

Elstead snorted. ‘Bullshit. Make sure you record this, Junge. I’ll enjoy showing this to old MacNerny at Cornell and make that pompous pedant eat his words …’

The sun ballooned, quite suddenly, to became a crimson wall that covered half the sky; black forms like monstrous sunspots crawled across it. Then it popped, flinging out material. For a second the space around us was laced by streamers of glowing gas, green and gold and blue, lit up by the solar remnant. But the nebula dispersed in an eyeblink.

‘So that’s that.’ Elstead said, matter-of-fact.

I asked, ‘What about Earth?’

‘If it wasn’t swallowed by the red giant, by now it will be a ball of hardened slag under a thin shell of frozen nitrogen. What do you think of that, Susie? London, New York, Bethlehem, Mecca – all gone. But our ‘scopes don’t have the resolving power to find it.’

‘Three billion years,’ I said. ‘How much further will we go? Ten billion? A hundred?’

‘Oh, further than that.’ Elstead smiled. I was coming to hate his mind games.

I noticed my gold crucifix still floating in the air. I grabbed it and hung it around my neck, and began to unbuckle. ‘I think I’ll go to my cabin—’

Junge touched my arm. ‘No. Wait. Brace.’

The ship shuddered, and a cold light flickered behind the stars.

‘Gravity waves,’ Junge muttered. ‘The merging of the big black holes from the centres of the two colliding galaxies. Brace for aftershock …’

Again the Bathyscaphe rocked and bucked, its hull metal groaning, as we fell deeper into time.

I was on the bridge in the middle of the next day, our third, when we passed the next milestone.

Elstead had served up lunch, in ceramic trays piping-hot from the microwave oven. We ate at our stations with the trays clipped to our laps. My choice was a pasta bake. The galley mostly served up ‘astronaut food’, as I thought of it, dried food like biscuits, or dinners bound to the plate by glue-like gravies and sauces. I’m told the Russians do it better.

Around us the stars of our new elliptical galaxy swarmed, nameless, slowly fading as the aeons ticked away.

‘Depth, twenty-five billion years,’ Junge called. ‘The Big Crunch. Here we go…’

I was alarmed enough to stop eating. ‘The Big Crunch – a reverse of the Big Bang, right?’

‘Yes,’ said Elstead.

‘When all matter, all space and time, will be crushed out of existence.’

‘Yes.’

‘Including us?’

‘It’s a possibility—’

Junge held up a hand.

I stopped breathing. I clutched at my couch’s armrests, as if that was going to help.

Nothing happened. The stars continued to shine, fading gently.

‘We’re through it,’ Junge said. ‘Next destination the Big Rip, in another fifteen billion years.’ He glanced at his timers. ‘Maybe an hour.’ He turned back to his food.

‘So no Big Crunch,’ I said.

‘No Big Crunch,’ Elstead said. ‘And, please note, resident journalist, we have made our first significant cosmological discovery. Susie, I think you need to ask me the second of your big questions.’

I nodded. ‘ Why , then? Why make this journey?’

‘Simple. To learn the answer to the most fundamental question of all: what is to become of us, in the end?’ He began to lecture me, and through me posterity. ‘Susie, when I was a kid the universe looked pretty straightforward. The dominant force was gravity: everybody agreed on that. We knew the universe had come barrelling out of the Big Bang, and gravity controlled the future. If the mass density of the universe was too high, if gravity was too strong, then the universe would reach some maximum radius and start to fall back on itself. Otherwise the universe would expand forever. Big Crunch, or endless dissipation. But that simple picture fell apart when those anomalous distant-supernova results turned up in the 1990s. And now the answer to that epochal question about the universe’s ultimate fate depends on the properties of dark energy, which are unknown.

‘In the most extreme scenario, suppose the density of the dark energy is decreasing with time. Suppose it even goes negative. If that happens it will become attractive , like gravity. The universal expansion will slow quickly, and then reverse. A Big Crunch, soon. But we have already descended through the most likely epoch for a dark energy crunch. In the process we’ve proven something about the properties of the dark energy too, do you see? This is an exploration not just of cosmology but of fundamental physics.’

I glanced uneasily at Junge, who quietly watched his timers. ‘And the Big Rip?’

This was predicated on a different theoretical model for dark energy, and was still more spectacular. Perhaps the dark energy could become stronger with time. A positive feedback effect could cut in. The final expansion would be sudden and catastrophic.

‘Five minutes to the Rip,’ Junge said.

Again I gripped my couch.

‘Now you know my objective,’ Elstead said. ‘To observe directly our cosmological future – to see which of many possible outcomes we must endure – and thereby, incidentally, to confirm various models of fundamental physics by direct inspection of their far-future consequences. What a goal it is! You know, I made an awful lot of money through doing awfully little. A slightly different kind of implanted cell phone, just good enough to beat out its competitors: I made billions, but it’s an achievement that will be forgotten in a century. This , though, will live in the imagination forever. I know people call me grandiose. But I’ve had my kids, made them all implausibly rich. What else should I spend my money on…?’

And as Elstead talked about himself we lived through the five-minute barrier, and survived a sixth minute, and a seventh. No Big Rip; more dark energy models eliminated.