The basic location had suggested itself
naturally enough. Gantt had briefly considered a shipboard
experiment in the ocean west of San Diego, but he concluded that
the delicate measurements he hoped to make would be virtually
impossible with the present equipment on board a pitching ship.
Even on this solid land where he now stood, the natural tremors of
the Earth could mask any small effect, and he did not really know
what effect to anticipate.
He mentally surveyed the layout. Arrayed over
several miles of barren rolling desert were a series of
seismometers to measure the ordinary activity of the Earth, and the
special seismic waves that were due to be superposed. There were
also the special instruments designed to detect any accelerations
that might occur if a significant gravitational pull, in addition
to that of the Earth, were to occur. All these instruments were
connected to a small but powerful computer energized by the
portable generator the noise of which disturbed the otherwise quiet
early afternoon. This computer would provide an instant analysis of
the data. It not only recorded the strength of the signals but,
using information from instruments spaced at a distance, it could
also triangulate and determine the direction and distance to the
source of the waves or gravitational acceleration.
All was now in readiness. Gantt felt a small
chill despite the heat. In a little over an hour the seismic waves
should broach the surface about two hundred miles away in eastern
Arizona, registering on the seismometers but perhaps only
marginally on the accelerometers even with Runyan’s most extreme
estimates. Eighty and a half minutes later the source of the waves
would again approach the surface but a thousand miles to the west,
over seven hundred miles off the Pacific coast. Since the
incommensurate period of rotation of the Earth made the surfacings
appear to shift one hundred ninety miles every twenty-four hours,
tomorrow at nearly the same time the waves should impinge on the
surface very close to their present location.
Gantt turned his back on the encampment and
looked out across the shallow hills. He had great difficulty
accepting the picture proposed by Runyan, and yet he could not
resist a morbid temptation to imagine what was proceeding if the
hypothesis were correct. A small speeding object was now plunging
down through the deepest basalt layers of the Earth’s crust. In
fifteen minutes it would enter the molten core, picking up speed as
it went. Sensing the change in gravitational pull as it passed the
Earth’s center, it would begin to slow as it shot back toward the
surface, where it would peak with majestic slowness before crashing
back into the dirt and rock.
Gantt shook his head and strode back to the
main tent of the encampment. The interior of the tent was a little
cooler because of the air conditioner installed to service the
computer, but it was still stifling. Gantt became too engrossed to
notice.
At five minutes before the appointed time, he
focused his attention on the needles of the seismometers. They
jiggled steadily, but with nearly constant amplitude, tuned to the
basic constant sounds of the Earth. In a couple of minutes he saw
the effect he was looking for. The swings of the needles on all
three seismometers began to slowly grow in amplitude. Danielson’s
seismic waves were real enough all right. The question was what
caused them. Even to Gantt’s trained eye the signals on the three
instruments looked identical. Only the computer could distinguish
the minute differences due to the slightly different distances of
the instruments from the source of the waves. Gantt turned to the
computer, typing rapidly on the keyboard and then scrutinizing the
screen in front of him as the printer to one side began to roll out
the same data on a chain of paper sheets. The distance was about
one hundred ninety miles, a little closer than their best guess,
but within the expected errors. Gantt’s gaze then swung to take in
the readings from the accelerometers that might detect some
variation in gravitational force. He thought he could make out the
briefest fluctuation, but could not be sure. Again he keyed the
computer and found his impression confirmed. There might be an
effect, but it was only marginally above the noise level. A more
sophisticated analysis that could only be done with time and a
bigger computer might dig something out, but for now there was no
firm conclusion to be reached. Still, he mused, an effect of the
size Runyan predicted could not be ruled out. If the minute
fluctuation were real, then something massive had just surfaced two
hundred miles away, and in three quarters of an hour it would do so
again on the far side of the Earth.
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 that 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 behavior 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 that 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 toward the
fighter. “We landed before we took off.”
“Holy cow!” 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
adventure!”
He helped her through the passenger hatch in
the side of the helicopter, handed 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 buckled 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 the 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 program. 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 of her 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.”
“Did you explain Alex’s hypothesis to the
Navy?” Gantt wanted to know.
“No,” replied Danielson, “the decision was
made not to spread that notion any further than necessary until the
results of this expedition are in.” She leaned toward Gantt. “What
about this cessation of the signal below the surface that you
reported yesterday? My data have never shown a signal from the
upper mantle, but you reported a definite time delay. That would be
a small effect in my data that have poor time resolution, but it
might be present. I didn’t have time to look carefully before
hopping the plane. Don’t you think it’s reminiscent of the sonar
signal stopping at the surface of the ocean, just that it starts
earlier and lasts a bit longer?”
“Yes, that’s my impression,” said Gantt.
“It’s strange behavior for a normal seismic wave, but it might be
consistent with Alex’s beast as we discussed in La Jolla.” He
paused to scratch his head and shuffle his toe in the dirt. “Still,
I can’t help wondering whether we could be dealing with some
special fissuring that focused normal seismic waves, and those
fissures could terminate below the surface.”
“But that wouldn’t explain the delay in the
return of the waves,” Runyan pointed out, “nor the holes drilled in
Nagasaki and Dallas.”
“Well, maybe the energy is temporarily stored
as a mechanical stress in the rock and then released. I admit I
don’t have a real physical picture of such a process, but neither
do I see how to rule out the possibility. The holes? Well, you’re
right; I can’t account for them easily either. Coincidental
imperfections in the concrete?”