The Krone Experiment (31 page)

“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 blotched 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 millimeters to a centimeter. 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 us 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 loathe 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 that 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
foundations 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 that 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
super- sonically?”

“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 center, though. I’ll have to think some more
about that.”

“Gentlemen,” cut in Phillips 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 that 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 thing
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
times. 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. “Tungus?
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 rivaling the old one in Arizona.
The best idea seems to be a comet. Comets are thought to be very
loose filamentary 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 Carl 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 Tungus 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 toward 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.”