Pat Danielson was home. Her relief had turned to elation during Drefke's lecture to them the previous Friday afternoon. As he droned on in sombre tones, she slowly realized that he was not only reinstating them, he was granting Isaacs full authority to pursue Project QUAKER. She had invited Janine out to one of their favourite spots and had got gaily tipsy before dinner. Returning to the apartment, she had succumbed to a spontaneous urge and called her father in Los Angeles and made plans to spend the weekend with him.
She enjoyed it immensely, being back in the small house so flooded with childhood memories, now gently nostalgic in her buoyant good mood. She and her father took walks down familiar sidewalks, the cracks in them so much closer together than when she had played hopscotch along them. They talked long and avidly, sharing experiences past and present. More balm on the wound in their relation, now nearly invisible. Long Beach and the ocean were only two miles away. She spent Sunday afternoon on the beach, alternately body-surfing, jogging, and soaking up the sun, a teenager again. She rediscovered the simple pleasure of sitting on the seawall and watching the world go by — sunburned throngs on bicycles, roller skates, skateboards, even a few ordinary pedestrians, all in constant motion up and down the miles of beachfront sidewalk. She thought a lot about Project QUAKER and their scheduled meeting with Jason to renew their consultation. She thought about Alex Runyan. She looked forward to seeing him again.
Late Monday morning, she flew down to Son Diego and met Isaacs's incoming flight. By early afternoon, they were back in Ellison Gantt's room closeted with the same members of Jason. Both Wayne Plumps and Alex Runyan had greeted them on their arrival. Runyan, again in. shorts, T-shirt, and thongs, had attached himself to Danielson, escorting her with friendly chatter up the stairs and to a seat on the comfortable, slightly frayed sofa next to the portable blackboard. She had self-consciously enjoyed the attention. Now she looked around noting with amusement the tendency for people to resume the positions they had previously established, even three weeks before, some instinctual territoriality, she supposed. Noldt and Fletcher sat in the same chairs, next to the sofa. Noldt's round face beamed as he greeted her again. Fletcher had just come in from a run on the beach, his dark lean face still flushed and his hair wet from a shower. Gantt was again seated at his desk, looking as grey and undistinguishable as ever. Zicek and Leems came in. Leems scowled and took the chair by the door, but Zicek smiled and joined the pair on the sofa.
Plumps and Isaacs remained standing by the door until Zicek was seated, then Plumps spoke. 'Gentlemen, you remember Dr Danielson and Mr Isaacs and the novel problem they brought to us before. There have been a number of developments, among which is the change in status of this situation. They came to us informally before to seek what wisdom we had to offer. Now they are here on highest priority official status. I urge you to listen carefully to their new information and to address this problem with all the acumen at your command. I've no doubt that when you have heard the latest developments you'll need no further goad from me. Mr Isaacs.'
'Thank you. Professor Plumps.' Isaacs clasped his hands behind his back and looked around the room, last and longest at Harvey Leems seated close to his left side. 'You'll recall that Dr Danielson had predicted that our regular seismic, sonar signal was to impinge on Nagasaki on July 7 and on Dallas July 26, just a week ago.
'For Nagasaki we stationed a ground observer in the area and obtained high resolution aerial reconnaissance photographs. At about the predicted time, a chlorine tank in a nearby warehouse sprang a leak. A workman in the warehouse was killed by gas inhalation, and a number of others were hospitalized with lung damage. The tank was punctured with two holes approximately a centimetre in diameter. A vertical line through these holes was aligned with a similar hole in the concrete floor. The hole appeared to extend into the subsoil beneath the foundation, but there is a high water table and moist soil obliterated any sign after a few centimetres. The skylight above this line of holes was broken out. In the street we found a truck with its engine blown. There were signs of odd damage to it, but it had been moved and we can't determine with certainty that there is a connection. The aerial survey photos showed nothing.'
'While you're on that point,' Runyan interrupted. 'I had some astronomical colleagues take photos of the points in space the signal seems to travel between. Same result, zip.'
'I see,' said Isaacs. 'That's interesting.' And maybe not too smart, he thought to himself. If they had found something, a big goddamn cat could have been out of the bag.
'In Dallas ,' he continued, 'the details were different, but the overall picture was the same. Two buildings were damaged. In one, there is a hole roughly a centimetre across from the roof down through the basement. Again, evidence for penetration into the subsoil, but in Dallas it was too sandy to support the tunnel, or whatever it was. Once again there was a death, incidental, but related. A young woman was crushed when a structure collapsed on her.'
'How's that?' asked Noldt, his owlish face screwed in concentration.
'Well,' Isaacs paused, 'this was a two-storey place with a bar underneath and a strip joint upstairs.' He gestured with his hands flat, one above the other. 'The woman was, uh, dancing upstairs. This tunnel, or whatever it was, weakened a support structure on the stage and it collapsed on her.'
'I see,' said Noldt, sitting up straighter in his seat, a little embarrassed.
'A hundred metres away,' Isaacs continued, 'the rear quarter of a seven-storey building gave way and collapsed into the alley behind it. In this case, fortunately, no one was injured. The cause of the structural failure has not been positively determined, although some pieces of masonry show elongated gashes which bear similarity to the holes in the concrete floors in the other damaged buildings in Dallas and Nagasaki. Two agents in the area reported hearing a whistling noise of some kind. Their impression was that it receded up from the bar, and one of them thinks he heard it again about forty seconds later, prior, he believes, to the collapse of the building. There is no question now in my mind that this thing, whatever it is, causes physical damage, and that it was similar effects that damaged the Russian aircraft carrier, the Novorossiisk, and sank our destroyer, the Stinson.'
'You say,' remarked Zicek, 'that this phenomenon seems to have gone up and then down in Dallas , in consonance with your feeling that something goes back and forth in the earth.'
Isaacs nodded. 'I remind you that I remarked before I didn't see how any beam could do such a thing, reverse directions. That feeling seems to be reinforced with your new evidence.'
'Wait a second, now,' Leems broke in. 'What about satellite locations? I need to be convinced that more than one source isn't involved somehow, one shooting one way, one, the other.'
'I checked that,' Danielson responded to him. 'There are hundreds of Soviet satellites in orbit. Occasionally, there was a marginal coincidence of position with a single event, but no pattern that could explain all the incidents we know of. And no case when two satellites lined up on the trajectory simultaneously on opposite sides of the earth to account for the reversal of direction.'
She looked down and brushed a piece of lint from her skirt and then looked back at Leems.
'I also tracked all US, European, and Japanese satellites, with again the same null result. Nothing currently in orbit can account for what we have seen, even discounting the question of what the technology could be, something that could propagate through the earth.'
Beside her, Alex Runyan smiled lightly, taking pleasure in her neat parry. Leems scowled more deeply, but did not respond. After a long quiet moment, Danielson leaned around Runyan to address Zicek.
'Excuse me, Dr Zicek, but there's another thing that I'm not sure came out clearly just now. The marks that we've investigated, the holes in the concrete, look very clean. There's no sign of a great release of energy, no blackening, no melting or fusing of the material. Perhaps that makes the situation more confusing, but there's no indication of explosion or burning which you'd expect of radiation from a beam of energy. It looks more like the material was drilled out; it's just gone.'
The group of scientists fell silent, thinking. Fletcher and Noldt muttered to one another.
The idea hit Runyan like a physical blow. Suddenly he was encased in a suit of armour from neck to groin, three sizes too small. He stared at Danielson, and she returned his look, her right eyebrow arched quizzically.
Runyan felt as if he were balanced on a vertex. He sensed the grip of forces of which he had been unaware until moments ago. Danielson's words had lifted a curtain to reveal the crest and the chasm yawning immediately before him. Random moments from his career flashed out of his subconscious, and he perceived them as stepping stones that had led him inexorably up to this teetering edge. He had no choice but to take the step that would send him plummeting headlong down the other side.
He knew the antagonist. He knew the mathematical structure of its bones and sinews, its space-time stretched tight on this frame. He knew the roaring cauldron.deep inside which marked the boundary where knowledge stopped, but from where new beginnings would inevitably arise. He knew the men and women, past and present, who had pieced it together in their imaginations, fragment by careful fragment.
But this was not imagination. This was not mathematics. This was the most delicate dreams of the intellect come real in nightmare fashion. And that reality changed everything. Everything.
He had an urge to close his mind, as if by sealing off the thought he could seal the abyss, but he knew it was there. A dynamic, hurtling, all-consuming void.
'Do you have a pen, some paper?' Runyan whispered hoarsely to Danielson. He was scarcely breathing.
Danielson rummaged in her purse and produced a pen and a small airline cocktail napkin she had salvaged on the flight down.
'I only have -' she started to say.
'Fine' Runyan breathed, grabbing the pen and napkin, 'that'll do.'
He pressed the napkin onto his bare knee and began to scratch symbols and numbers on it, oblivious to the uncertain, dispirited conversation in the room. Danielson was confused by his action, but could feel a new tension radiating from him. She had trouble following the discussion. Even though he was completely ignoring her, she felt partially mesmerized by Runyan's newly focused intensity. She found this intensity, contrasted with a potential for warm amiability, strangely attractive.
Runyan was uncertain how much time had passed when he finally drew a long breath and let it out slowly. He banded the pen back to Danielson and locked eyes with her for a long moment. Then he stuffed the napkin into a pocket of his shorts and waited for a break in the discussion. At an appropriate point he poked a finger up.
Phillips nodded at him. 'Dr Runyan. You have a thought?'
Runyan lapped his fingers together and leaned forward, forearms on his bare knees. He pressed his thumbs in opposition, looked down at his hands and then up towards Phillips. His terrible conclusion was inescapable. Now he had to lead his colleagues down the same path.
'Let me see if I can speak to what is bothering all of us,' he said slowly and reflectively. 'We've been unable to account for any extraterrestrial source, natural or artificial. The fact that we're dealing with something that has a fixed direction in space suggests an origin out there.' He jerked a thumb towards the ceiling. 'But the basic phenomenon occurs within the depths of the earth.' He jabbed a long forefinger towards the floor. 'It only comes to the surface periodically.'
Danielson sat tensely on the sofa, partially turned towards Runyan, watching his eyes and mouth as he spoke. The words were neutral enough, but seemed darkly ominous to her, a cold vapour filling the room.
'Incredible as it seems,' Runyan continued, 'I think the conclusion we've been avoiding is that there is actually something inside the earth, something moving around through the earth, triggering seismic waves and tunnelling holes as it goes.'
He glanced sideways at Danielson, his eyes crinkled by a faint smile. 'I don't remember whether it was Sherlock Holmes or Nero Wolfe who argued that one should throw out every impossible explanation, and the remaining one, no matter how improbable, must be the truth.' The smile faded. 'I've done something like that in my own mad and reached a conclusion, but it's bizarre, and I don't want to prejudice you with it yet. I'd like you 'o follow this line of reasoning and see where you think it leads.'
Runyan seemed to be sitting calmly, looking around at his colleagues, but Danielson happened to glance down at his feet. His toes were curled around the end of the thongs, gripping them, pale splotches on the knuckles contrasting with the tanned skin.
Across the room, Isaacs was staring at Runyan, mentally groping, trying to grasp the implications of the scientist's statements. The quiet was broken by Fletcher who sat up straight in his chair and muttered, 'Oh, Jesus.' He swivelled to look at Runyan. The two locked gazes and stared at one another for an extended moment. Then Fletcher broke off and waved a hand inviting Runyan to take the floor.
Runyan stood and made his way slowly to the blackboard, deep in thought. With a habit born of long hours in the classroom, he selected a moderately long piece of chalk from the tray before turning to face his audience.
'Let's forget the seismic signal itself and concentrate on the derived trajectory for a moment,' he began, unconsciously slipping into a pedagogical tone. He turned to the board and sketched a circle representing the earth, with a curved arrow above it indicating the direction of rotation. Then he added a straight line beginning a third of the way from the equator to the North Pole which passed through the centre of the circle and out the opposite side.
Watching the tip of the chalk, Danielson suddenly pictured a stiletto, piercing the earth. Her shoulders contracted in a brief shiver.
'The source moves like this,' Runyan tapped the line with the chalk, 'with a period of eighty minutes and thirty seconds. We can think of the earth as a sphere of roughly constant density which produces a certain gravitational potential. An object falling freely in that harmonic potential would oscillate back and forth along a line. To close approximation, the line would point to a fixed direction in space. The period would be eighty some-odd minutes.' He looked at Fletcher, then at Leems. 'Essentially the same as that of an earth-orbiting satellite.'
There were scattered rustlings in the room as a couple more individuals began to see where Runyan's arguments were leading.
'Now, if we consider the real earth,' Runyan continued, 'there would be some differences. A minor factor would be that the density of the earth is not constant. An orbiting object would feel a somewhat different gravitational pull than the idealized case I've described. That would alter the period of the trajectory somewhat. There could also be processional effects on the orientation, but all that's negligible for now.'
He looked around the room, focusing briefly on Danielson. Her stomach tightened as if his gaze were a physical grip. ml face was a sharp image against blurred surroundings. She could make out beads of sweat along his hairline.
'The significant feature,' Runyan continued, 'is that the path is anything like a free orbit since, as we all know, the earth resists quite effectively the attempt of any material. body to move through it. If I'm on the right track, the orbiting body can't be ordinary material.'
'Let me get this straight,' said Gantt. 'You're proposing that something is actually orbiting within the earth?'
'C'mon!' snorted Leems.
'That's the only picture that makes sense to me,' Runyan replied, his voice tensing at the implied scepticism. He turned to the board and drew heavily, repeatedly, on the line that slashed through the circle. 'Back and forth on a line fixed by the inertial frame of the stars, independent of the rotation of the earth. That's been one of the strangest features of the story Dr Danielson has told us.
'The problem,' he continued, 'is to identify what the thing could be. It's apparently slicing through the earth l& the proverbial knife through butter. That seems to call for something significantly denser than the densest parts of dm mantle and core, denser than anything occurring naturally on earth or made in any laboratory.'
'I don't see where you're going,' said Leems sceptically 'Are you talking about some superheavy element?'
Runyan glared at him. He could see the answer so clearly Was Leems being deliberately obtuse?
'In a sense,' he replied, Godly. 'My thoughts go to stellar examples, where high densities naturally result from huge gravitational fields.' He glanced at Fletcher who gave a brief nod. 'White dwarf matter, which is crushed until atoms blur into one another, exists at densities from million to a billion grams per cubic centimetre. Neutron star material is even more extreme. Matter is squeezed until atomic nuclei dissolve at densities greater than a hundred trillion grams per cubic centimetre. If you could drop a chunk of either kind of matter on earth, it would meet virtually no resistance and plunge to the centre and pass through to the opposite side as it performed an essentially free orbit.'
'Are you suggesting a neutron star is orbiting inside the earth?' asked Gantt incredulously.
'No,' Runyan replied, frowning. 'A full-sized white dwarf would be as large as the earth and have as much mass as the sun. A neutron star would only be a few miles across, but again would have the mass of the sun. The earth's orbit hasn't been appreciably affected since the astronomers haven't raised an uproar, so whatever we are dealing with can't have much mass.'
'Then you're talking nonsense, aren't you?' It was a statement more than a question from Leems.
Runyan ignored him. 'We might consider a small piece of a neutron star or a white dwarf, but we understand the physical processes involved there reasonably well. Freed from the gigantic self-gravity, a small piece would explode under its own outward pressure. What we need is something which will remain at high densities even though it has relatively low mass. Although I can list reams of practical objections, I can only think atone possibility which fits the picture we now have.'
Leems was exasperated. 'Honest to god, Alex,' he said in a disgusted voice, 'you're not making any sense at all. What in the hell are you getting at?'
Runyan's resolve to proceed dispassionately dissolved.
'Oh, for chrissake, Harvey !' he stormed. 'Can't you see it?' He was suddenly angry that the responsibility for the message was his. He aimed his fear and frustration a Leems.
'It's a black hole!' he raged. 'The earth's being eaten b; a goddamned black hole!'
Danielson recoiled back against the cushion of the sofa a Runyan's outburst, her face draining of colour. Black holes! Her mind reeled at his vehemence, the radical leap of hi! argument. Black holes had to do with stars, space, galaxies Not downtown Dallas , Nagasaki. What in god's name was he talking about?
'Oh, bullshit!' blurted Leems. He locked eyes with Runyan and then looked down and away to a neutral pain in the room.
'What?' demanded Noldt. 'What did he say?' Fletcher: leaned over to him and began an intense reprise of Runyan'! arguments.
Runyan continued to glare at Leems and made m attempt to respond to the commotion. He felt the first wisp: of relief that the burden was no longer solely his to bear.
Good god! Have I blundered? Isaacs thought to himself as he sat upright in his chair. With a sinking sensation, hl looked quickly from Runyan to Leems, and back t< Runyan. Was coming to Jason a grievous error? Was hi innate distrust of these far-out academics finally justified He could feel his months of work and risk slipping away What a disaster, if all he had to take back to Drefke was some harebrained idea. He turned to Plumps with a look o dismay.
Phillips saw the startled concern on Isaacs's face. As he stood and moved to the front of the room beside Runyan he surveyed the others. Leems was red-faced, as if he'd picked up the colour Danielson had lost. Fletcher was still explaining, waving a finger back and forth, tracing trajectory in front of the nose of a bewildered Ted Noldt. Gantt and Zicek were attempting a disjointed analysis across the length of the room, their voices ringing with surprise. Phillips motioned for quiet.
'Gentlemen,' Phillips said firmly, 'let's see if we can have an orderly and objective discussion of this remarkable suggestion Dr Runyan has made.' Turning to Runyan he continued, 'Alex, you'll have to forgive our collective scepticism, but this notion strains all credibility. From where could such a thing have come? What could it be doing in the earth? Surely, there's a simpler explanation.'
When he answered, Runyan's voice was still too loud, his normally avuncular tone replaced by a hint of righteousness.
'Simple? What we all crave is a less radical solution. We've striven for that and come away empty-banded. I submit we won't find a simple solution in the sense you mean, Wayne. Only an orbit fits the odd trajectory. Only an orbit would have a fixed period and a direction anchored in space, independent of the earth's rotation about its axis and revolution about the sun. Can anyone deny that a simple orbit fits the picture?'
The rhetorical question was greeted with silence. Runyan paced back and forth in a tight little orbit of his own. Danielson's thoughts were awash with the idea he had thrust upon them. Her eyes watched the muscles flexing in his sun-tanned legs. His tone became calmer.
'I ask myself what sort of thing can be orbiting through the earth, and I see no alternative to the conclusion that it is very dense. Ordinary, even extraordinary matter can't exist in small quantities at extreme densities, so I'm forced to conclude that we are dealing with a small, but very deadly, black hole. Don't get the idea I'm happy with this idea. On the contrary. It scares the hell out of me.'
He continued to pace, thinking.
'Here's more support for it,' Runyan said. 'Look at the holes drilled in solid concrete with no sign of searing or scorching. That's one of the singular pieces of evidence and very hard to understand any other way. It's just what a small black hole would do. A black hole will pull in matter from a volume much bigger than itself as it moves, the gravitational force sucking the material in from the immediate vicinity.' He made a crushing motion with his fist. 'A black hole will carve a tunnel as it goes, but leave no other sign of its passage, not like a laser beam or any other such device, as Dr Danielson was quick to see.' He smiled at her for a moment. 'In fact, from the size of the holes left behind, I can estimate the mass of the thing.'
Runyan paused and dug into a pocket of his cutoffs and brandished the napkin. The numbers Matched irregularly where the ink from Danielson's pen had run in the porous material. He did this more from a sense of drama than from a need to refresh his memory. He recalled the result perfectly well. He made an abbreviated OK sign with index finger and thumb and peered through the small hole at his audience.
'The holes drilled are about this size,' he said, 'a few millimetres to a centimetre. Depending on the tensile strength of the material through which the hole passes, I would guess the mass to be comparable to a small mountain and its size to be about that of an atomic nucleus.'
'But would a small black hole do what we are observing?' Gantt asked. 'That is, if it knifes through the earth as if it were butter, how does it generate the acoustic signal?'
Runyan pondered for a moment. 'Well,' he began, 'as I've said, it would exert a force sucking in matter from the immediate vicinity. It would carve a tunnel as it went. Does that suggest anything?'
'I suppose,' replied Gantt. 'At least in subsurface rock the ambient pressure would prevent such a tunnel from existing except momentarily. I can imagine the collapse of such a thing generating acoustic waves, depending on the size.'
'That's a good point,' Runyan aimed a blunt finger at him, 'the size of the tunnel is related to the mass of the object and the rate at which the tunnel forms and collapses should give an estimate of the acoustic power — which we know! Can we check to see if the picture is self-consistent?'
Gantt joined Runyan at the board and they began a crude, but rapid calculation. They stood in front of their figures and symbols to the consternation of those in the room trying to follow the arguments. After a few minutes of gesticulation and occasional cursing, Gantt returned to his seat.
'With some uncertainty,' Runyan announced, 'the acoustic signal is consistent with the idea of a small tunnel continuously being drilled at the orbital velocity and then collapsing.'
'I'm sorry,' Isaacs said, his voice polite, but firm. 'This is very important because you're talking about the basic data that led to this thing.' If Runyan were off base, Isaacs wanted to nail him quickly. He also recognized that the notion of a black hole and its implications were too foreign to him to be absorbed rapidly. If it turned out to be more than a crackpot idea, he didn't want to miss details that would aid his ultimate understanding. 'Could you explain to me a bit more clearly what you just did.' Isaacs gestured at the board.
'Oh, sure.' Runyan was loath to halt the flow of ideas, but recognized his responsibility to Isaacs. 'The picture is that a small black hole will move without resistance through the rock of the earth's core. It's like a little vacuum cleaner, sucking up particles that it gets too close to. The mass of the black hole dictates the strength of the gravitational pull it exerts. Close to the black hole that gravitational force is overwhelming, but at larger distances the tensile forces of the rock which make it solid are stronger than the gravity of the black hole. The quantitative question is to determine the distance from the black hole at which the internal forces in the rock are stronger than the gravitational pull of the hole. Further than that, the rock remains intact. Closer than that, the suction of gravity is dominant. If you were somehow to hold the hole still, it would eat out a cavity the size of which is proportional to the gravity of the black hole and hence to its mass. If the hole has a mass comparable to a small mountain, as I said, then it will carve a hole of about the diameter that you've reported in the foundation of those buildings.'
'Okay,' Isaacs replied, 'I guess I see that. And you get a tunnel rather than single hole if this black hole moves along a path sucking up everything out to a certain distance.' He pinched an imaginary particle between thumb and forefinger and moved it methodically in a line at arm's length.
'Exactly,' Runyan confirmed.
'Then where does the seismic signal come from?'
'Ah!' Runyan exclaimed. 'Now picture this hole falling freely through the rock at a speed which is determined by the gravitational acceleration of the earth. That speed determines the rate at which this little tunnel is carved.
'But what happens to the tunnel?' Runyan proceeded to answer his own question. 'After the black hole moves on, the tunnel can't just sit there. The huge pressure in the surrounding rock will crush it. So there's a continuous process by which the hole carves the tunnel and then moves on leaving the pressure forces to collapse it. The seismic signal is very plausibly the continuous noise made by the collapsing tunnel.'
'That can't be the whole picture,' Isaacs was thinking hard. 'At the surface, in normal rock, you should just get a hole drilled, just as we've seen in these concrete foundations.'
'Good, good. That's very perceptive.' Runyan was a little condescending, but he looked at Isaacs with new respect. 'In the mantle the pressure forces are not as great and the wound of the tunnel should remain unhealed. I remind you that the strength of your seismic signal falls as the influence nears the surface. Pat said there was no detectable signal from the upper mantle. This could be exactly the reason!'
'What about the acoustic signal in the water?' Isaacs inquired.
'Probably a similar idea with cavitation.'
'Cavitation? You mean like with a motorboat propeller?'
'Right. The hole should consume a surrounding volume of water just as it does rock. After it moves on, the water will rush into the vacuum in its wake creating thousands of tiny popping bubbles. Cavitation, and acoustic noise.'
'It looks to me,' Fletcher pointed at the board, 'as if you've assumed the hole moves subsonically. What if it moves faster than the material can respond. What if it moves supersonically?'
'I don't think that's a problem except maybe in the liquid iron core of the earth where the hole would be moving at its highest speed,' Runyan replied. 'Whatever this is seems to move relatively slowly at the surface — fast, but slower than the speed of sound in rock, water, or even air. There could be shock waves near the earth's centre, though. I'll have to think some more about that.'
'Gentlemen,' cut in Plumps from the side of the room where he had been standing, 'I'm impressed with the virtuosity of your arguments, but I'm still very disturbed at the nature of your conclusions. Doesn't anyone have an alternative suggestion?'
The question was greeted with silence. Runyan stood mute. His eye rested on, but barely registered, a dollop of coffee on the desk, spilled from a cup Gantt had brought in after lunch. His fixation was broken by Ted Noldt who stirred and said, 'I have a question which bears on the possibility of a black hole.'
Runyan lifted his eyes and looked at the speaker. 'I don't know much about black holes,' Noldt said, 'but I thought the small ones, about which you are talking, were supposed to radiate away their mass and energy at a great rate, causing them to evaporate and explode. Doesn't that rule out such a black hole?'
'We're going to have to consult a real expert on the subject, which I'm surely not,' replied Runyan. 'That question has been very much on my mind.' He paused a moment and then continued. 'Here's a possibility. The theory of evaporating black holes was worked out in the context of idealized, empty space, whereas this one's in the real world!' He caught himself. 'Sorry. A grotesque pun. Unintentional. Anyway, maybe the fact that this one is surrounded by matter changes things.'
'That may be right,' mused Fletcher, picking up the argument. 'If it's consuming matter, the infall may squelch the outflow. Let's see, didn't you and Ellison estimate the rate of consumption just now?'
'Right,' said Runyan, turning to the board once more. 'I don't remember all the formulae for the evaporation rate, but maybe I can piece something together.' He doodled for a minute while the others looked on and listened to the scratching chalk. 'Yes!' he looked up. 'That's probably it: there seems to be a comfortable margin. As long as the hole bores through the earth, it will eat the matter and grow. You'd have to stop the consumption to get it to evaporate.'
'Wait a minute,' said Noldt, punching a finger in the air. 'That's not really relevant, is it? This flung must have come from space somehow, so it must be massive enough not to have evaporated before it got caught in the earth. Isn't that right?'
Runyan beetled his brows at Noldt and paced along the narrow corridor in front of the blackboard a couple of tunes. Then he turned to face him again.
'No,' he said, 'I'm not sure that is right. It's true that the cosmologists have told us about the possibility of such mini— black holes created in the turbulence of the Big Bang. But there are two problems. In the first place, though my estimates are crude, I don't believe this object is massive enough to have survived since the beginning of time. Secondly, there is a great difficulty with the curious fact that it moves with the earth.'
'What's that?' Noldt was puzzled.
'If this were a black hole born in space,' Runyan explained, 'there is little chance that it could get trapped in the puny gravity of the earth. For that to happen, it would have to be moving very slowly with respect to the earth. But what with the earth's motion around the sun and the sun's motion around the galaxy and the galaxy's motion off to god knows where, the relative speed between the earth and any random astronomical body would be much greater than the escape velocity from the earth. The earth could not possibly attract and hold anything moving past it so rapidly.
'Do you remember the Tungus event?' he asked Noldt. Noldt had to think for a second, "fungus? Russia. Siberia ! Big explosion?'
'Right,' Runyan replied. 'Still rather mysterious. Some explosion in Siberia in 1919. Burned and flattened trees for miles around. But no crater. That ruled out a large meteorite. Any piece of space rock big enough to do the damage done would have to have left a crater rivalling the old one in Arizona. The best idea seems to be a comet. Comets are thought to be very loose fragmentary icy structures. Such a thing could deliver a hell of an impact but be sufficiently diffuse not to gouge a crater.'
'So?' Noldt did not see the point.
'Well, whenever something strange happens somewhere, someone is going to suggest a black hole.' He broke off and looked at Leems scowling at him. 'I know what you're thinking, Harvey. If the shoe fits... But hear me out.
'There was a suggestion that the Tungus event was caused by a small black hole. Then it would just dig a small tunnel as I've described, not make a large crater.
'This idea was quickly ruled out though, for just the reason I said. Any black hole coming in from space would have to be moving at a huge velocity, at least a hundred times greater than we're dealing with here. The question earl raised a minute ago is pertinent. Such velocities are supersonic and the hole arrives with a large shock wave. That's what was supposed to cause the Tungus blast itself. But then when the hole went through the earth it would have generated seismic waves that would have pinned seismographs all over the earth, and while the 'Fungus event itself was registered, nothing like the passage of a supersonic black hole occurred.
'Finally, you can trace the angle of impact from the pattern of flattening of the trees. Any such black hole should have reemerged in the Baltic Sea and blown Norwegian fishing boats out of the water. From all reports, they fished peacefully that day.
'So the hypothesis of a black hole from space ultimately made no sense there.' Runyan looked directly at Noldt again. 'And it makes no sense here either for the same reasons. The velocity would be too high. But whereas a low speed black hole would not have caused the Tungus event, a low speed black hole fits what we've seen here.' He nodded towards Isaacs and Danielson.
Noldt thought for a moment. 'Well,' he said, 'suppose the universe is littered with these things, and we just happened to have the bad luck to finally overtake one slowly, and it settled in.'
'We don't know anything about the distribution of such holes in space, of course,' said Runyan. 'No evidence for them has ever been observed. To have enough small black holes to make the interaction you describe probable, I would think they would have to be so densely distributed that we would have noticed many other astronomical effects.'
'I don't understand what you are saying,' stated Noldt.
'What is the alternative? Surely such a thing doesn't occur spontaneously on earth?'
'No, I don't see how it possibly could,' agreed Runyan.
'I don't see how it could have occurred naturally on or off of the earth.' He paused, unable to avoid sounding portentous, and somewhat embarrassed at doing so. He was determined not to speak next.
After a moment, Leems spoke up with an edge in his voice. 'If we accept your arguments up to this point, then we're forced to the conclusion that this thing was manufactured. Is that what you're saying?'
Runyan nodded, but remained silent as all eyes shifted towards him. At last he said, 'That's the second conclusion I've reached. I think we must allow for the possibility unless it can be rigorously ruled out.'
Again Runyan became silent as he exchanged glances with his colleagues, desiring to support, but not lead the discussion at this critical juncture.
'There are two possibilities then, aren't there?' asked Fletcher. 'It's man-made or...' He paused and finally said in a flat voice, 'Or it's not.'
'Omigod!' exclaimed Noldt. 'You mean this thing could have been manufactured by extraterrestrials and... and planted here?'
Several voices were raised in simultaneous protest.
'This is getting out of hand!'
'UFO's again! That's very hard to believe!'
Isaacs had a flash of memory of the AFTAC headquarters in Florida where he had first heard of the seismic signal. He couldn't believe what he was hearing. How could that simple little rattle in the earth be related to the insanity that was being expressed in this room! Then he thought of Zamyatin. Whatever was going on, he couldn't feature explaining black holes to the KGB chief, never amid trying to convince him they were being fired by nasty little green men from outer space. He shook his head and pinched his eyes with thumb and finger. This discussion just had no connection whatever with the real world of geopolitical confrontation with which he dealt every day.
Runyan cut in. 'I'm sure we agree that the whole situation is hard to believe!'
'The energy requirements to make such a thing must be gigantic,' said Leems. 'Surely the suggestion that it's artificial is absurd.'
'It would take a lot of energy,' Runyan agreed. 'Don't you think it's fair to conclude then,' Leems pressed, 'that such a thing would be exceedingly difficult, if not impossible, to create? I have a strong suspicion we're on the wrong track altogether despite your argument here.'
'I don't deny that point,' replied Runyan. 'It's very difficult to conceive how such a thing could be done.'
'Still,' argued Noldt, 'it's not that it's impossible, just that we can't see how it could be accomplished technologically. Isn't that correct?'
'I think that's correct,' said Runyan. 'We're talking about very large amounts of energy, but not an infinite amount. In principle, it could be done. After all, we're fairly comfortable with the notion of it happening spontaneously in an astronomical context. Also, the large energy you're thinking about is based on brute force compression. There may be more elegant means to the end.'
'Then,' said Noldt with a barely suppressed excitement, 'since we see no way to do it on earth, aren't we forced to consider the possibility that such a thing was made by extra-terrestrials and put in the earth for some purpose?'
'Before we invoke some malevolent intent, terrestrial or otherwise,' Leems said with scarcely veiled sarcasm, 'I must say I'm not satisfied that we really know enough to rule out a natural origin. Even if we accept that we're dealing with a black hole, and I'm as yet far from convinced of the necessity, how can we eliminate the possibility that this thing started out exceedingly small a long time ago? Maybe the earth even condensed around it, and it took all this time, five billion years, for it to grow to its present size.'
'I have two responses to that,' Runyan said. 'One is that the universe was already quite old when the earth was born. There were no special conditions at the time to create small black holes, and any born in the Big Bang should have long since evaporated.'
'Well then, figure out a way to prevent evaporation,'
Leems said harshly. 'That still seems more likely than insisting on some intelligent plot at work.'
'Maybe so, maybe so,' Runyan said slowly. 'The other thing that bothers me is that the growth time for this thing is relatively long. I find it peculiar that this phenomenon has only just been discovered, since the technology to detect it has been around for some time.'
'Are you saying that this dung has just been put here recently?' asked Noldt. He half-glanced over his shoulder as if expecting to catch a glimpse of an alien presence.
After a moment's hesitation, Runyan spoke again. 'I'm disturbed that we're skirting a bit close to the edge of reason here with too few facts to support us.' He cleared his throat, then continued. 'Perhaps we should set aside for a while the issue of how such a dung could come to be and try to consider some other factors. We should discuss what we can do to learn more about this object.'
'I've been thinking about that,' said Fletcher, 'as a remedy for incipient hysteria.'
Pat Danielson had been following the discussion intently. She had felt herself becoming more edgy as the tension in the room increased. She had read some popular accounts of astronomy and their discussions of black holes and thought she was beginning to make some sense from Runyan's remarks, but the idea that he would leap from the evidence she had compiled to this conclusion still left her stunned. And now talk of manufacturing such a dung. That just couldn't be. She joined the nervous laughter after Fletcher's remark and could sense the more relaxed mood that spread through the room.
Fletcher continued, 'There should be quite a bit one could do by adopting your hypothesis as a working assumption and constructing appropriate models. If we could predict the behaviour of a small black hole, or whatever, orbiting through the earth, we could compare such predictions with the seismic data and other observations and perhaps get a much better idea of just what we are dealing with. Ideally, we should be able to prove your hypothesis true — or false.'
'Ah, a voice of reason,' said Leems, in a more lively tone. 'I don't know much about seismic waves, but it still seems to me that they should be modelled as well, to see whether the data that have been reported can be accounted for as some natural seismic phenomenon. The data are admittedly quite bizarre, but surely our seismologist friends don't know everything about the workings of the inner earth. Maybe there are special fissures or lattice works that channel waves in this special way.
'I do concede, though, Alex,' Leems continued, 'that since you have let this particular genie of yours out of the bottle, it should be pursued.'
'That's right,' agreed Noldt, 'if we are, in fact, dealing with a black hole and it originated on the earth's surface, then, if I have the picture correctly, it should return roughly to its point of origin.'
'I wish you wouldn't assume it was made on the earth's surface,' interrupted Leems.
Noldt gave him a befuddled glance and continued, gesturing towards Isaacs and Danielson. 'We already have reasonably accurate predictive capabilities. We can predict when and where the thing is due to come up and, well, of course you don't just grab it, but surely we could learn more about it then.'
'In fact,' added Fletcher, 'shouldn't an orbit tell us just where the origin was with respect to the surface?' Leems frowned again, but did not say anything.
'Yes, exactly right,' said Runyan. 'If we compare the apogee, the point farthest from the centre of the earth, to the earth's topography, that should give us some pertinent information. We already have an interesting indication from the Dallas event so nicely predicted by Dr Danielson.' He nodded at Danielson and she smiled quickly in return. 'About forty seconds elapsed from the first episode in the bar to the destruction of the building across the alley. An object in free fall could not have risen and then fallen more than a few thousand feet. So apparently apogee is somewhat above sea level, but not far. The point at which the orbit peaks will occur deep under mountains of any height, the Rockies or the Himalayas. More precise information of this sort could be most useful.'
'If we can tell where this thing comes out of the earth, what sort of test can we run?' asked Noldt. 'You can't see such a thing can you?'
'No,' answered Runyan, 'it's about the size of an atomic nucleus. You surely couldn't see it directly. It's most distinctive characteristic, of course, would be its gravitational field. That should be quite appreciable. Gravimeters set up in the vicinity should be able to tell us precisely what the mass of the object is, whether or not it comes to or through the surface. A simple seismic wave will have no effect on the local strength of gravity. A massive, orbiting object, on the other hand, should give a definite signature.
'I propose that this be our first move, and that since Gantt is our resident seismologist, he's the man to mount such an expedition.' Runyan turned to Gantt. 'What do you say, Ellison? If Dr Danielson can predict where the event will approach the surface at a given time, won't you be able to measure or set stringent limits on the fluctuations of the gravitational field?'
'That's an excellent ideal' responded Gantt with enthusiasm. 'I'll start planning immediately.'
Runyan glanced at Leems and then inquired, 'What do you think of that, Harvey ?'
Leems clasped his fingers together and stared at them for a moment. 'The gravity seems to be an effective discriminant. By all means, let's put your idea to the test.'
Gantt raised a finger and inquired, 'How well can you predict the point of surfacing? Can Dr Danielson's estimates be improved?'
'I think there's much to be done with computer models,' responded Runyan. 'I sketched a crude hypothetical orbit on the board. There will be many perturbations to an idealized orbit, but to work those out in detail can be done with sufficient effort. In addition, there may be some effect from the sun and moon, and perhaps the larger planets. With the exception of the effect of the structure of the inner earth, which is not known precisely, computation of a detailed hypothetical orbit should be possible.'
'Who would do these orbit calculations?' inquired Noldt.
'The people with the expertise,' replied Runyan, 'are those who calculate satellite orbits. They've already developed techniques to handle inhomogeneities in the earth's gravitational field as well as perturbations of the sun, moon, and planets. The effect of irregularities in the interior of the earth have not, of course, been studied in that context. Incorporating the effects of structure on the orbit should be possible in some approximation, though. There will also be drag forces, since the orbiting object will be accreting and, if nothing else, losing energy into the seismic waves we are detecting.'
There was a pause as these various practical considerations were pondered.
'At the risk of leading us back to the brink of insanity,' began Fletcher after a moment, 'I think we should at least touch upon one more item. I know we would all rather go after experimental results than to speculate with insufficient data, but I think we are charged here with exploring all avenues, at least in a preliminary fashion.' He looked sharply at Runyan. 'What should be done if you're correct, Alex?'
This query plunged the room back into an uncomfortable silence. The relief that had come with the discussion of the dispassionate collection of data was replaced with general discomfort. No one was anxious to contemplate what could only be a dreadful prospect.
Leems spoke first. 'Surely it's premature, but, yes, let's play the game out.'
'Perhaps I should lead off,' Runyan spoke quietly.
'Though I confess I have nothing definite, and certainly nothing positive, to say on the subject.' He paused, collecting his thoughts, sensing again the yawning chasm.
'Black holes are notoriously one-way affairs. They get bigger. A black hole will eat and grow like a cancer in the bowels of the earth. Where it does orbit above the surface, it becomes accessible in a sense, but it's not clear that that does us much good. As Ted remarked earlier, you don't just load something the size of an atomic nucleus and the weight of a small mountain in the back of a truck and haul it off. We have two choices: destroy it, or remove it from the earth. The hell of it is, I don't see any way of doing either.'
After a moment's quiet, Fletcher spoke. 'There's a third choice, isn't there?' He looked around at his colleagues. 'Evacuate the earth.'
'Good lord!' ejaculated Leems. 'Let's not get morbid.' 'earl's not trying to be morbid,' said Noldt with some heat. 'We need to explore all the possibilities, and he's just being honest.'
Fletcher gave a quick nod of acknowledgement in Noldt's direction and then addressed himself to Runyan. 'If it is a hole, Alex, how fast is it growing?'
'That depends rather sensitively on how massive it is and the structure of the material it passes through,' Runyan remarked. 'The time to double in mass could be several thousand years.'
'As short as that!' exclaimed Noldt.
'I could easily be off by a factor of ten. It could be longer.' He looked Noldt in the eye. 'Or it could be shorter.' He glanced around at the group. 'This is a crucial point that earl has raised. Any estimate of the time scale will require a knowledge of the mass, which makes the effort to measure the mass even more important. In any case, if we are dealing with a black hole, it will only grow at an ever increasing rate. We'll never have any longer to figure out what to do about it than we have right now.'
'Do you have any idea how quickly it will become dangerous?' Fletcher wanted to know.
'Again, I can make some guesses as to what will happen,' replied Runyan, 'but I can't say just when without more information.
'If it is a black hole and we can't get rid of it, it will continue to consume the matter of the earth. We'll have to look at the details more closely. This will be part of the orbit calculations I just mentioned. It may, for instance, eat the liquid core faster than the solid mantle, although it's travelling faster in the core and that may mute the effect. In any case, it's riddling the mantle with small holes. Either consuming the core or weakening the mantle will induce earthquakes of increasing magnitude. The drag associated with its motion will eventually cause it to settle into the centre of the earth. Not only will it then be irrevocably out of reach, but the core will be rapidly consumed.
'As the molten core of the earth is consumed, the earth will shrink. That in turn will remove the pressure support that holds up the giant continental plates. They will begin to rapidly shift and collide, in turn giving rise to another source of destructive earthquakes. All of this seismic activity will cause severe volcanic activity and tidal waves. As the hole gets to be near the mass of the earth, the earth will begin to oscillate in orbit, as it revolves around a common centre of mass with the hole. This will drastically enhance the destruction.
'Finally, the hole will grow so large that it will rapidly ingest the last of the core and large chunks of mantle. The outcome will be a black hole with the mass of the present earth, but only the size of my thumb.' He made a fist with extended thumb for illustration. 'In the end there will be nothing but the moon orbiting a small black nothingness, maybe along with a ring of rocks that managed to avoid being pulled in.'
The group of people in the room sat silently, mesmerized by this gloomy prediction. Caught up in the story he was spinning, Runyan paused, but then proceeded on an afterthought.
'I'm sure it's of only academic interest, but one can carry the story to its end. This small black hole and its moon would continue to orbit the sun. After several billion years, the sun will swell to become a red giant and will engulf the hole. If the earth still existed at that point it would be vaporized in the fire. But if the black hole has done its work, the tables will be turned. The process will begin again but with the sun the victim. The hole will slowly spiral down through the matter of the sun. It will settle to the centre and consume the whole sun in the space of a few years. That black hole, now immensely massive but only a few miles across, and its remnant planets, if any, will then proceed through space until the end of time.'