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.'