Hild settled back in her chair, suspended at the centre of the science desk’s big glass bubble, and spun slowly around, glancing over the various feeds.
Boyd, slower and stiffer, and Salma, young and eager but just a mite clumsy, turned too.
Before Salma now one large screen carried a real-time image of Planet Nine, relayed by close-in camera drones, heavily processed and enlarged – but nothing to see, nothing but a perfect sphere, perfectly black – to the naked eye anyhow. Only centimetres across. She knew that the black hole was in fact subtly flattened at the poles, an oblate spheroid, the event horizon distorted by the hole’s spin. And then there were the mysterious patterns in the Hawking radiation, invisible to a naked human eye.
In addition there were images returned from free-flying drones, further out. Just in case something dramatic happened on a larger scale. All you could see of what those returned was star fields.
Ten Earth masses, crammed into an object, as Boyd had once observed, no larger than a human head. And now we dare to approach it, Salma thought. To challenge it. To roar back at the lion. Not that she’d ever seen a lion outside of downloads from Earth.
Hild snapped, ‘Enough staring. Enough wonder. Enough awe. Time for science. Joe, can you confirm a comms lock back to the Outpost?’
‘As well as the laws of physics allow,’ Joe Normand called in, with his usual deep drawl.
And Salma knew what he meant, that the various systems were aligned, and signal pulses already sent would reach the Outpost three days later, limping out at lightspeed, pulses focused using panels of their vast solar sail as an antenna – all would reach home unless their status changed drastically.
‘Propulsion?’
Zaimu Oshima called in briskly from the engine control deck. ‘Ready to get us out of here if you say so, Hild … The landing pod is ready to go too.’
‘Good. Stand ready. And, navigation …
Salma quickly consulted screens, systems, backup systems. ‘All looks good.’
This was one of Salma’s own specialities, and not a demanding one in the normal course of things, given the slowness of the craft, and the emptiness of the outer Solar System through which they had travelled. Even now it was a straightforward task, with the relative position of the ship and the target – Nine – observed, measured, triangulated against the Sun, distant stars and other landmarks routinely selected by the systems. Salma wondered vaguely if the smart automatics were learning to lock onto that red spot in Sagittarius – unmoving, as it turned out, over a number of days, so presumably a very distinct beacon …
She was wool-gathering. Focus, Salma.
‘We are exactly where we should be,’ Hild said now. ‘Around a hundred and thirty thousand kilometres out from Planet Nine, for the sake of anybody who hears this when the signal arrives, wherever you are. Twenty Earth radii out … OK, Salma. It’s time. Send your signal.’
Salma checked her monitors. ‘Beam aligning. Ship’s position steady, locking onto Nine …’
Salma herself was to be given the privilege of giving the final send command. She held her hand over the relevant console, trying not to tremble visibly.
‘All right,’ Hild said. ‘Hold steady. Clock counting down from thirty seconds.’
Twenty Earth radii. Always they referred back to Earth for such comparisons, Salma had observed.
Salma wondered if this message, and recordings of the incident as a whole, would actually be passed on from the Conservers’ Outpost to Earth itself – and maybe the Moon too, that other knot of a nascent extraterrestrial civilisation. Only after some kind of security deal, she imagined. She hoped so, she imagined so. Surely a situation like this, which might impact all of mankind – and for all time, if it did turn out to be some kind of exotic first contact – demanded openness from the start. For the consequences would surely be unending.
That was the way a Conserver thought, she knew – but perhaps not the way Earth or the Lunar Consortium would react, given their deepening rivalry over the future of the Solar System and its treasures of metals and water and nitrogen and fusion fuel. Was it best, then, that it was a Conserver ship that had found this anomaly? Perhaps it could only have been a Conserver ship, in this epoch anyway; the thinly scattered resources of the Oort cloud were not yet the focus of those growing, rival, materialistic cultures.
Nothing here for them, Salma thought. Or so they believed. So only we came here, to the dark. And, lurking in that generous dark—
On a screen, a digit turned to five, four, three …
‘Two, one, lock,’ Salma said briskly. She was still holding her hand over the contact pad. A deliberate gesture was required for such a grave moment, she knew. No chance of a misfire because of a poorly pronounced word, or a hesitant button-push … ‘Permission to send the message?’
Boyd sighed. ‘And with one touch of the finger of a twenty-year-old, the future will change irrevocably.’
Salma asked again. ‘Commander?’
‘Permission—’
Salma laid her hand flat on the terminal.
And even as she completed that motion the contact must have been made.
At lightspeed, Salma knew, it would have taken just two-fifths of a second for the signal, rich in emulation of the Hawking-radiation patterns, to cross the twenty-Earth-radii gap to Nine. Two-fifths of a second back, the minimum time for any response to be visible. Fragmentary intervals, over before Salma was even aware of them.
But. Nothing.
She was aware of everybody holding their breaths, Hild at her station, Boyd expertly scanning the various readouts and displays around the cabin. Watching, watching.
And when the change came, it was sudden.
‘Shit,’ Boyd Hart said.
Hild was out of her chair and at his station in a heartbeat. ‘Tell me what you’re seeing … Oh.’
Boyd stabbed at a screen, shared, enhanced and expanded his display with a stroke of stiff fingers. ‘You know that before now we’ve been sending down radar pulses, just routine pings. You get some echoes back from the ergosphere – you don’t get reflections from the event horizon, but you get some of the ping energy being thrown back out at you, the photons coming back after a half-orbit around, or one and a half—’
‘I understand. Not a reflection, but it works that way.’
‘Yeah. Well, suddenly that echo interval is dropping. As if the hole, the event horizon and all the mess outside, is expanding. And uniformly.’
Hild stared. Then she snapped out, ‘Go to one of the cloud drones. Further out.’
Boyd hit another screen.
And Salma saw what looked like an immense bubble, pitch black, spreading across the star fields. Briskly scattering the residual hot, ionised gases that had gathered in the black hole’s gravity well. Spreading, growing rapidly; within seconds the drone’s field of view was utterly obscured.
Hild snapped out orders. The free-flying drones pulled back fast, to enable them to see, to avoid being hit by that bubble – whatever it was.
‘And this started …’
Boyd checked. ‘Yeah, just as our message ping reached the event horizon. Umm. And the echoes are different too. It’s reflecting more like a solid surface now, rather than a gravity well. Simpler echoes, less distortion, not the multiple orbits of light we saw before.’ He glanced up at Hild. ‘And it’s still expanding. I guess we woke up the tiger.’
‘Well, I’ve never seen a tiger. Zaimu, stand ready to get us out of here if you have to.’
Zaimu Oshima called back from his station at propulsion. ‘Just say the word, Hild, checked and ready.’
Salma put in, ‘Boyd’s right that we’ve evoked a response, though.’ She felt excited, even thrilled.
But Hild was worrying about her ship. ‘Maybe. But since when did black holes expand? What’s next? Let’s just keep working, folks, monitoring, measuring, thinking … Expanding, you say. How fast?’
‘Umm … around thirty kilometres a second now,’ Boyd said. ‘And pretty uniformly. A neat sphere.’
‘And we are, what, a hundred and twenty thousand kilometres out? So that will take—’
‘About an hour for the event horizon to reach us. If that surface still is an event horizon. At that rate. But I think it’s already slowing.’ Boyd’s hands flew across his screens with remarkable precision, Salma thought. ‘Modelling it … That horizon is a pretty sharp surface, and the speed curves are smooth. It looks like it will slow up at about three Earth radii, perhaps a little more. Slow to a halt …’
Hild glanced at his modelling. ‘If you’re right, it’s going to settle down to that radius in, what, ten minutes?’
‘About that. Fitting data points as we have them. Look, the prediction tracks are converging already …’
‘He’s right,’ Salma called, excited, nervous. ‘It’s behaving itself. Whatever it is. And I’m studying the surface as it approaches. I seem to be seeing some kind of leakage radiation too. Less exotic. The Hawking signals and traces are still there, but the surface around the traces, and patches nearby, seems to be glowing. In the infra-red. Invisible to the eye, but—’
‘Glowing like what?’ Hild snapped. ‘You need to give me more than that, Salma.’
Salma said, feeling baffled, ‘I don’t know what to report first. It’s as if the effective surface temperature of the black hole – well, whatever this is, it’s no black hole, not any more, not physically; the temperature of Nine – is climbing fast. I mean, it was close to absolute zero a few minutes ago, and now …’
Boyd was staring back at Salma. ‘You say it’s climbing fast. Bet you ten to one your curves are already levelling off.’
‘I hadn’t projected them that far. The data is patchy—’
‘So’s mine. Use what you have.’
‘I … OK. Yes. The models haven’t quite converged, but it looks like it’s flattening at around—’
‘Two eighty-eight Kelvin?’
‘I was going to say three hundred. Around thirty Celsius … No, it’s dipping below that …’
Boyd laughed, rubbed his face with one huge hand. ‘Of course it is. Three Earth radii. It all fits. Let me know when it reaches two eighty-eight or so.’
Hild murmured, ‘That number’s familiar …’
‘Space-dwellers ought to have it by heart.’
Hild scowled. ‘This situation is spiralling out of control. Just tell us, Boyd, enough with the riddles. Have you figured out what’s going on here?’
‘I think so. This thing is smart. From the beginning, this black hole, whatever it is, has been communicating with us. The Hawking radiation patterns. We echoed them back, right? We don’t know what it was saying, but that’s our most basic way to say, Here we are! We’re listening! We swapped signals. We announced our presence.
‘So since then it – whatever this thing is, no simple black hole – has been tracking other signals, from the Conservers, the traders on the Moon. It’s probably been monitoring us since it arrived here. And Earth itself, the loudest, brightest, hottest, noisiest of all. To an alien visitor, it’s a fair bet that that would look like our origin world, don’t you think?’
‘I don’t know what to think—’
‘And now here we are, and it’s – making us welcome.’
‘Welcome?’
‘Oh,’ Salma said. ‘I get it. Two eighty-eight Kelvin. Fifteen Celsius. That’s Earth’s average surface temperature.’
Hild frowned. ‘Earth. Oh, wow. So it knows about Earth, and about us. I feel – I feel a deep conceptual shock unfolding, deep inside. Earth’s temperature. OK. And this sudden expansion to three Earth radii—’
Boyd said, ‘This black hole – no, this Nine, this artefact – masses ten times Earth. And a planet, or a planet-shaped body, with ten Earth masses and three Earth radii gives you—’
‘One standard gravity at the surface, just about,’ Hild said. ‘Wow.’
‘Newton could have worked that out,’ Boyd growled. ‘But the significance—’
‘It’s making us welcome,’ Salma said slowly. ‘We showed it where we come from – or gave it enough data to figure it out – and now it’s inviting us in. The right gravity, the right surface temperature.’
‘Not that welcome,’ Meriel the doctor called in. ‘No air down there. No sunlight, or anyhow not strong enough for photosynthesis – you couldn’t sustain a biosphere. But, gravity and heat – it will be the second most comfortable place in the Solar System for humans, after Earth itself. You could land, safely. And it only just got here. Quite a stunt. And doesn’t that tell us more?’
Hild frowned. ‘Such as what?’
‘Such as, it wants us to land.’ That was Zaimu, calling in from propulsion. ‘In case you haven’t thought of it yet: the escape pod’s well capable of landing down there, Hild. Since it’s capable of landing on Earth. The gravity well is deeper but … Using a fission engine is a sinful lapse for us Conservers, but in the circumstances – the lander could go down there and bring me home. It’s well capable of that, even without aerobraking.’
‘“Me”?’
‘Let me go,’ Salma said immediately. She looked at Hild wildly. ‘I’m the youngest. The most adaptable.’
Boyd snorted. ‘“Most expendable” would be a better argument.’
‘Come with me, then, Salma,’ Zaimu called in immediately. ‘You may be expendable but you can’t fly the pod.’
‘Have you ever heard of automatics? All I’d need do is set a course—’
‘And when the landscape on this chimera of a world changes again?’
‘I just mean—’
Hild held up a hand. ‘Shut up, both of you, and let me think.’
Boyd looked over at her. ‘You have to send someone in. They’re right about that. Come on, you can’t refuse this invitation. It’s first contact with extraterrestrial life, after all. The first contact with extraterrestrial intelligence. Evidently. And it’s an obvious invitation.’
‘Let him go down,’ Salma said. ‘And – let me go with him.’
Hild buried her face in her hands.
And elsewhere, elsewhen—
To smile was a human reflex.
Yet now, it could be said, Terminus smiled.