Gantt stripped the printed computer output off the machine and examined it more carefully. He swore quietly as sweat dripped off his brow onto the paper, obscuring a few numbers. He stopped to wipe his forehead and neck and then returned his attention to the rows of numbers. The seismic waves stopped several miles below the surface. After a minute or so, the source of the waves began again, moving nearly vertically down into the earth. Gantt felt a nervous tightening across his abdomen. An ordinary seismic wave could be reflected, but it did not wait a minute while making up its mind. Such a delay might occur if the source of the waves moved up into light surface layers which were not conducive to the production of waves and then fell back again. Runyan's hole could do that. Deep in thought, Gantt sat for some minutes striving for an explanation in terms of the normal behaviour of the earth as he knew it. Nothing occurred to him, but he told himself that Runyan need not be right on that basis, perhaps it was just his own lack of imagination or lack of sufficient information. The mysterious interior of the earth had surprised him more than once and might be doing so again. Taking solace from that thought, he proceeded to a close study of the data acquired during the event.
Wednesday morning Pat Danielson clambered down from the rear seat of the jet-black F-16 which was rigged for tactical reconnaissance. She was aided by the pilot and a ground technician. Her legs were a little unsteady from the excitement of the Mach 2 flight from Washington — over two thousand miles to the Yuma Air Station in an hour and a half. She followed a young marine to a waiting helicopter and stood there while he went into a nearby utilitarian terminal building. He reemerged in a moment followed by Alex Runyan. Runyan was halfway across the tarmac when he looked up and saw her. The look of surprise and pleasure on his face was delicious to her.
'Pat!' He ran forward, grabbed her hand in both his and gave her a spontaneous peck on the cheek, oblivious to the watching servicemen. 'What a delight. I didn't expect to see you here.'
'After you pleaded with Bob Isaacs yesterday,' Danielson said gaily, 'we decided to coordinate the trips, save a helicopter ride.'
'That's great. When did you leave? It's a long way.' She laughed with obvious glee. 'Crossing three time zones helps, but so does that,' she pointed towards the fighter.
'We landed before we took off.'
'Holy cowl' Runyan exclaimed. 'Now I know who has the real clout. I thought I was Mr Big with the puddle jumper your boss arranged for me this morning. Well, let's get on with the adventurer
He helped her through the passenger hatch in the side of the helicopter, banded up her light bag, then his and finally swung himself up and in with a single easy motion.
'What did you think of Gantt's preliminary report?' Danielson shouted over the whine of the cranking engine, as they budded themselves in.
'Too soon to tell,' he shouted back, 'but I'm afraid there was nothing to prove I was wrong.'
After they took off, the flight noise made conversation difficult. Danielson watched the country flash by the open hatch, vividly aware of Runyan's long lean thigh next to hers.
Gantt was engrossed in making some changes in the computer analysis routines when he heard the chopping roar of the approaching helicopter. He approached the landing site and stood a hundred yards off as the machine circled once around the area and then settled slowly to the ground. As die rotor speed decreased and the whine of the turbojet ceased, he saw a man get out and then turn to help his companion. Gantt squinted into the sun and then finally waved a greeting as he recognized the approaching figures.
'Hello!' shouted Gantt. 'Alex! What a surprise. I didn't expect an extra guest at our little party here.'
He shook hands with Runyan and then with Danielson. He grabbed the young woman's hand with both of his and gave an extra shake. He suddenly wanted Danielson to feel welcome as a colleague, rather than a visiting government official.
'Do you have baggage to unload?' he inquired.
'Just a couple of bags,' replied Runyan. 'Lord, it's hot here! What's the temperature?'
'About a hundred and fifteen in the shade,' Gantt laughed. 'Cools off in the evenings, though. Not so bad then.'
Gantt looked back and saw the pilot unloading two small cases from the passenger compartment. He called to one of the young marines who had been recruited for the project to lend a hand and then ushered the pair into the mess tent.
'Can I get you something? Coffee? Iced tea? Lemonade? Lunch won't be ready for a while, but we might scare up a snack.'
Both declined anything to eat. Gantt got a cup of coffee for himself and showed the others where to help themselves to iced tea. They sat at a table under the outstretched flap of the tent, shielded from the sun but open to the fitful breeze.
'Well, Alex, I needn't ask what brings you here, but it is a pleasant surprise.'
Runyan wiped his brow with the back of his hand and scratched his hot beard.
'I've been living with the computer at the Jet Propulsion Laboratory, adapting their orbital programs to calculate the path of a black hole through the earth. When you radioed your results from yesterday to CIA headquarters, Isaacs relayed the essence of it to me. I'd calculated so many orbital eccentricities that I was getting a bit eccentric myself. I'm afraid I was rather obvious about my desire to be out here where the action is, even though that wasn't on the programme. Lord knows I'll just be a fifth wheel.'
'In any case,' continued Runyan, 'I was picked up by an Air Force plane this morning and, much to my pleasant surprise, met Pat here in Yuma.'
'Well, I'm glad to see you both,' admitted Gantt. 'I confess I've been bothered by not having anyone here to talk to about this business. How are your calculations going?' he asked Runyan.
'The model basically fits the data. But there are lots of loose parameters. We don't know enough about the detailed structure of the inner earth and how a small black hole would interact with it to predict small subtle shifts in the orbit with any degree of confidence. A little extra rock, like the roots of a mountain range, can perturb the orbit slightly, depending on angle of approach, a bunch of things. You can get slow cumulative effects, or an occasional finite perturbation. Hard to pin down. The data you're collecting now should allow us to fix some of those parameters. That still won't be the same as proving my picture is right.'
'Actually,' interjected Gantt, 'if we are going to discuss this matter, and I surely want to, we should move over to my tent. It's a little less public there.'
They picked up their drinks and moved off to Gantt's tent which was set off somewhat from the main compound. Gantt went off to gather up two more folding chairs and returned to arrange them in the small patch of shade available.
'Have you learned anything new?' he inquired of Danielson.
'I've collated some more data from the Large Seismic Array and various other monitoring stations. There have been some refinements in our estimations, but nothing qualitatively new.' She took a sip other tea. 'In fact, there's been one major frustration. We had hoped to get the Navy to make systematic measurements of the sonar signal. That would have given us much better positions. Unfortunately, their old data isn't much good now, and they couldn't or wouldn't respond fast enough to get any new data this last week. As a result, the measurements of positions you got yesterday are probably the best we have.'