Obelisk

by Stephen Baxter

  She frowned. ‘What kind of storm? Oh. Neptune.’

  ‘Yeah. You can’t just delete a world without consequences. The planets’ orbits are singing like plucked strings. The asteroids and comets too, and those orphan moons wandering around. Some of the stirred-up debris is falling into the inner system.’

  ‘And if we’re struck—’

  I shrugged. ‘We’ll have to help each other. There’s nobody else to help us, that’s for sure. Look, Elspeth – maybe the Incoming and the Venusians are typical of what’s out there. But that doesn’t mean we have to be like them, does it? Maybe we’ll find others more like us. And if not, well, we can be the first. A spark to light a fire that will engulf the universe.’

  She ruminated. ‘You have to start somewhere, I suppose. As with this drain.’

  ‘Well, there you go.’

  ‘All right, damn it, I’ll join your think tank. But first you’re going to help me finish this job, aren’t you, city boy?’

  So I changed into overalls and work boots, and we dug away at that ditch in the damp, clingy earth until our backs ached, and the light of the equinoctial day slowly faded.

  OTHER TOMORROWS

  TURING’S APPLES

  Near the centre of the moon’s far side there is a neat, round, well-defined crater called Daedalus. No human knew it existed before the middle of the twentieth century. It’s a bit of lunar territory almost as far as you can get from Earth, and about the quietest.

  That’s why the teams of astronauts from Europe, America, Russia and China went there. They smoothed over the floor of a crater ninety kilometres wide, laid sheets of metal mesh over the natural dish, and suspended feed horns and receiver systems on spidery scaffolding. And there you had it, an instant radio telescope, by far the most powerful ever built: a super-Arecibo, dwarfing its mother in Puerto Rico. Before the astronauts left they christened their telescope Clarke.

  Now the telescope is a ruin, and much of the floor of Daedalus is covered by glass, moon dust melted by multiple nuclear strikes. But, I’m told, if you were to look down from some slow lunar orbit you would see a single point of light glowing there, a star fallen to the moon. One day the moon will be gone, but that point will remain, silently orbiting Earth, a lunar memory. And in the further future, when the Earth has gone too, when the stars have burned out and the galaxies fled from the sky, still that point of light will shine.

  My brother Wilson never left the Earth. In fact he rarely left England. He was buried, what was left of him, in a grave next to our father’s, just outside Milton Keynes. But he made that point of light on the moon, which will be the last legacy of all mankind.

  Talk about sibling rivalry.

  2027 AD

  It was at my father’s funeral, actually, before Wilson had even begun his SETI searches, that the Clarke first came between us.

  There was a good turnout at the funeral, at an old church on the outskirts of Milton Keynes proper. Wilson and I were my father’s only children, but as well as his old friends there were a couple of surviving aunts and a gaggle of cousins mostly around our age, mid-twenties to mid-thirties, so there was a good crop of children, like little flowers.

  I don’t know if I’d say Milton Keynes is a good place to live. It certainly isn’t a good place to die. The city is a monument to planning, a concrete grid of avenues with very English names like Midsummer, now overlaid by the new monorail. It’s so clean it makes death seem a social embarrassment, like a fart in a shopping mall. Maybe we need to be buried in ground dirty with bones.

  Our grandfather had remembered how the area was all villages and farmland before the Second World War. He had stayed on even after our grandmother died twenty years before he did, him and his memories made invalid by all the architecture.

  At the service I spoke of those memories, or rather of my father’s anecdotes about his father – for instance how during the war a tough Home Guard had caught Granddad sneaking into the grounds of Bletchley Park, not far away, scrumping apples while Alan Turing and the other geniuses were labouring over Nazi codes inside the house. ‘When my brother and I turned out academic, Granddad always said he wondered if he picked up a mathematical bug from Turing’s apples,’ I concluded, ‘because, he would say, for sure Wilson’s brain didn’t come from him.’

  ‘Your brain too,’ Wilson said when he collared me later outside the church. He hadn’t spoken at the service; that wasn’t his style. ‘You should have mentioned that. I’m not the only mathematical nerd in the family.’

  It was a difficult moment. My wife and I had just been introduced to Hannah, the two-year-old daughter of a cousin. Hannah had been born profoundly deaf, and we adults in our black suits and dresses were awkwardly copying her parents’ bits of sign language. Wilson just walked right through this lot to get to me, barely glancing at the little girl with the wide smile who was the centre of attention. I led him away to avoid any offence.

  He was thirty then, a year older than me, taller, thinner, edgier. Others have said we were more similar than I wanted to believe. He had brought nobody with him to the funeral, and that was a relief. His partners could be male or female, his relationships usually destructive; he brought them into the family like unexploded bombs.

  ‘Sorry if I got the story wrong,’ I said, a bit caustically.

  ‘Dad and his memories, all those stories he told over and over. Well, at least it’s the last time I’ll hear about Granddad and Turing’s apples.’

  That thought hurt me. ‘We’ll remember. I suppose I’ll tell it to Eddie and Sam someday.’ My own little boys.

  ‘They won’t listen. Why should they? Dad will fade away. Everybody fades away. The dead get deader.’ He was talking about his own father, remember, whom we had just buried. ‘Listen, have you heard they’re putting the Clarke through its acceptance test run?’ And, there in the churchyard, he actually pulled a tablet out of his inside jacket pocket and brought up a specification. ‘Of course you understand the importance of it being on Farside.’ For the millionth time in my life he had set his little brother a pop quiz, and he looked at me as if I was catastrophically dumb.

  ‘Radio shadow,’ I said. To be shielded from Earth’s noisy chatter was particularly important for SETI, the search for extraterrestrial intelligence to which my brother was devoting his career. SETI searches for faint signals from remote civilisations, a task made orders of magnitude harder if you’re drowned out by very loud signals from a nearby civilisation.

  He actually applauded my guess, sarcastically. He often reminded me of what had always repelled me about academia – the barely repressed bullying, the intense rivalry. A university is a chimp pack. That was why I was never tempted to go down that route. That, and maybe the fact that Wilson had gone that way ahead of me.

  I was faintly relieved when people started to move out of the churchyard. There was going to be a reception at my father’s home.

  ‘So are you coming for the cakes and sherry?’

  He glanced at the time on his tablet. ‘Actually I’ve somebody to meet.’

  ‘He or she?’

  He didn’t reply. For one brief moment he looked at me with honesty. ‘You’re better at this stuff than me.’

  ‘What stuff? Being human?’

  ‘Listen, the Clarke should be open for business in a month. Come on down to London; we can watch the first results.’

  ‘I’d like that.’

  I was lying, and his invitation probably wasn’t sincere either. In the end it was over two years before I saw him again.

  By then he’d found the Eagle signal, and everything had changed.

  2029 AD

  Wilson and his team quickly established that their brief signal, first detected just months after Clarke went operational, was coming from a source six thousand five hundred light years from Earth, somewhere beyond a starbirth cloud c
alled the Eagle Nebula. That’s a long way away, on the other side of the Galaxy’s next spiral arm in, the Sagittarius.

  And to call the signal ‘brief’ understates it. It was a second-long pulse, faint and hissy, and it repeated just once a year, roughly. It was a monument to robotic patience that the big lunar ear had picked up the damn thing at all.

  Still, it was a genuine signal from ET, the scientists were jumping up and down, and for a while it was a public sensation. But the signal was just a squirt of noise from a long way off. When there was no follow-up, when no mother ship materialised in the sky, interest moved on. The whole business of the signal turned out to be your classic nine-day wonder.

  Wilson invited me in on the tenth day. That was why I was resentful, I guess, as I drove into town that morning to visit him.

  The Clarke Institute’s ground station was in one of the huge glass follies thrown up along the banks of the Thames in the profligate boom-capitalism days of the early noughties. Now office space was cheap enough even for academics to rent, but central London was a fortress, with mandatory crawl lanes so your face could be captured by the surveillance cameras. I was in the counter-terror business myself, and I could see the necessity as I edged past St Paul’s, whose dome had been smashed like an egg by the Carbon Cowboys’ bomb of 2025. But the slow ride left me plenty of time to brood on how many more important people Wilson had shown off to before he got around to his brother. Wilson never was loyal that way.

  Wilson sat me down and offered me a can of warm Coke. His office could have been any modern data-processing installation, save for the all-sky projection of the cosmic background radiation painted on the ceiling. An audio transposition of the signal was playing on an open laptop, over and over. It sounded like waves lapping at a beach. Wilson looked like he hadn’t shaved for three days, slept for five, or changed his shirt in ten. He listened, rapt.

  Even Wilson and his team hadn’t known about the detection of the signal for a year. The Clarke ran autonomously; the astronauts who had built it had long since packed up and come home. A year earlier the telescope’s signal processors had spotted the pulse, a whisper of microwaves. There was structure in there, and evidence that the beam was collimated – it looked artificial. But the signal faded after just a second.

  Most previous SETI searchers had listened for strong, continuous signals, and would have given up at that point. But what about a lighthouse, sweeping a microwave beam around the Galaxy like a searchlight? That, so Wilson had explained to me, would be a much cheaper way for a transmitting civilisation to send to a lot more stars. So, based on that economic argument, the Clarke was designed for patience. It had waited a whole year. It had even sent requests to other installations, asking them to keep an electronic eye out in case the Clarke, stuck in its crater, happened to be looking the other way when or if the signal recurred. In the end it struck lucky and found the repeat pulse itself, and at last alerted its human masters.

  ‘We’re hot favourites for the Nobel,’ Wilson said, matter of fact.

  I felt like having a go at him. ‘Probably everybody out there has forgotten about your signal already.’ I waved a hand at the huge glass windows; the office, meant for fat-cat hedge fund managers, had terrific views of the river, the Houses of Parliament, the tangled wreck of the London Eye. ‘OK, it’s proof of existence, but that’s all.’

  He frowned at that. ‘Well, that’s not true. Actually we’re looking for more data in the signal. It is very faint, and there’s a lot of scintillation from the interstellar medium. We’re probably going to have to wait for a few more passes to get a better resolution.’

  ‘A few more passes? A few more years!’

  ‘But even without that there’s a lot we can tell just from the signal itself.’ He pulled up charts on his laptop. ‘For a start we can deduce the Eaglets’ technical capabilities and power availability, given that we believe they’d do it as cheaply as possible. This analysis is related to an old model called Benford beacons.’ He pointed to a curve minimum. ‘Look – we figure they are pumping a few hundred megawatts through an array kilometres across, probably comparable to the one we’ve got listening on the moon. Sending out pulses around the plane of the Galaxy, where most of the stars lie. We can make other guesses.’ He leaned back and took a slug of his Coke, dribbling a few drops to add to the collection of stains on his shirt. ‘The search for ET was always guided by philosophical principles and logic. Now we have this one data point, the Eaglets six thousand light years away, we can test those principles.’

  ‘Such as?’

  ‘The principle of plenitude. We believed that because life and intelligence arose on this Earth, they ought to arise everywhere they could. Here’s one validation of that principle. Then there’s the principle of mediocrity.’

  I remembered enough of my own studies to recall that. ‘We aren’t at any special place in space and time.’

  ‘Right. Turns out, given this one data point, it’s not likely to hold too well.’

  ‘Why do you say that?’

  ‘Because we found these guys in the direction of the centre of the Galaxy …’

  When the Galaxy was young, star formation was most intense at its core. Later a wave of starbirth swept out through the disc, with the heavy elements necessary for life baked in the hearts of dead stars and driven on a wind of supernovas. So the stars inward of us are older than the sun, and are therefore likely to have been harbours for life much longer.

  ‘We would expect to see a concentration of old civilisations towards the centre of the Galaxy. This one example validates that.’ He eyed me, challenging. ‘We can even guess how many technological, transmitting civilisations there are in the Galaxy.’

  ‘From this one instance?’ I was practised at this kind of contest between us. ‘Well, let’s see. The Galaxy is a disc a hundred thousand light years across, roughly. If all the civilisations are an average of six thousand light years apart – divide the area of the Galaxy by the area of a disc with a diameter of six thousand light years – around three hundred?’

  He smiled. ‘Very good.’

  ‘So we’re not typical,’ I said. ‘We’re young, and out in the suburbs. All that from a single microwave pulse.’

  ‘Of course most ordinary people are too dumb to be able to appreciate logic like that. That’s why they aren’t rioting in the streets.’ He said this casually. Language like that always made me wince, even when we were undergraduates.

  But he had a point. Besides, I had the feeling that most people had already believed in their gut that ET existed; this was a confirmation, not a shock. You might blame Hollywood for that. But Wilson sometimes speculated that we were looking for our lost prehistoric cousins. All those other hominid species, those other kinds of mind, that we killed off one by one, just as in my lifetime we had destroyed the chimps in the wild – sentient tool-using beings, hunted down for bushmeat. We evolved on a crowded planet, and we know something is missing, even if we forgot what we did and don’t know what’s wrong.

  ‘A lot of people are speculating about whether the Eaglets have souls,’ I said. ‘According to St Thomas Aquinas …’

  He waved away St Thomas Aquinas. ‘You know, in a way our feelings behind SETI were always theological, explicitly or not. We were looking for God in the sky, or some technological equivalent. Somebody who would care about us. But we were never going to find Him. We were going to find either emptiness, or a new category of being, between us and the angels. The Eaglets have got nothing to do with us, or our dreams of God. That’s what people don’t see. And that’s what people will have to deal with, ultimately.’

  He glanced at the ceiling, and I guessed he was looking towards the Eagle Nebula. ‘And they won’t be much like us. Hell of a place they live in. Not like here. The Sagittarius arm wraps a whole turn around the Galaxy’s core, full of dust and clouds and young stars. Why, the Eagle Nebul
a itself is a stellar nursery, lit up by stars only a few million years old. Must be a tremendous sky, like a slow explosion – not like our sky of orderly wheeling pinpoints, which is like the inside of a computer. No wonder the development of our own science began with astrology and astronomy. How do you imagine their thinking will be different?’

  I grunted. ‘We’ll never know. Not for twelve thousand years at least, if we have to send a question and wait for the answer.’

  ‘Maybe. Depends what data we find in the signal. You want another Coke?’

  But I hadn’t opened the first.

  That was how that day went. We talked of nothing but the signal, not how he was, who he was dating, not about my family, my wife and the boys – all of us learning sign, incidentally, to talk to little Hannah. The Eagle signal was inhuman, abstract. Nothing you could see or touch; you couldn’t even hear it without fancy signal processing. But it was all that filled his head. That was Wilson all over.

  This was, in retrospect, the happiest time of his life. God help him.

  2033 AD

  ‘You want my help, don’t you?’

  Wilson stood on my doorstep, wearing a jacket and shambolic tie, every inch the academic. He looked shifty. ‘How do you know?’

  ‘Why else would you come here? You never visit.’ Well, it was true. He hardly ever even mailed or called. I didn’t think my wife and kids had seen him since our father’s funeral six years earlier.

  He thought that over, then grinned. ‘A reasonable deduction, given past observation. Can I come in?’

  I took him through the living room on the way to my home study. The boys, then twelve and thirteen, were playing a hologram boxing game, with two wavering foot-tall prize fighters mimicking the kids’ actions in the middle of the carpet. I introduced Wilson. They barely remembered him and I wasn’t sure if he remembered them. The boys signed to each other: What a dork, roughly translated.

  I hurried him on, but Wilson noticed the signing. ‘What are they doing? Some kind of private game?’