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发信人: bhfbao (嗖嗖与嗖嗖), 信区: SFworld
标  题: Contact I-5
发信站: 哈工大紫丁香 (Wed Feb  2 15:23:09 2000), 转信

发信人: isabel (伊莎贝尔~戒网中), 信区: SFworld
发信站: BBS 水木清华站 (Thu Jan 27 00:52:54 2000)

发信人: Sandoval (Companion Protector), 信区: SciFiction
标　题: Contact Part I - 5
发信站: The unknown SPACE (Tue Jan 25 01:02:22 2000) WWW-POST

CHAPTER 5
Decryption Algorithm

Oh, speak again, bright angel...
-William Shakespeare
Romeo and Juliet
The visiting scientists' quarters were now all occupied,
indeed overcrowded, by selected luminaries of the SETI
community. When the official delegations began arriving from
Washington, they found no suitable accommodations at the
Argus site and had to be billeted at motels in nearby
Socorro. Kenneth der Heer, the President's Science Adviser,
was the only exception. He had arrived the day after the
discovery, in response to an urgent call from Eleanor
Arroway. Officials from the National Science Foundation, the
National Aeronautics and Space Administration, the
Department of Defense, the President's Science Advisory
Committee, the National Security Council, and the National
Security Agency trickled in during the next few days. There
were a few government employees whose precise institutional
affiliations remained obscure.
The previous evening, some of them stood at the base
of Telescope 101 and had Vega pointed out to them for the
first time. Obligingly, its blue-white light flickered
prettily.
"I mean, I've seen it before, but I never knew what
it was called," one of them remarked. Vega appeared brighter
than the other stars in the sky, but in no other way
noteworthy. It was merely one of the few thousand naked-eye
stars.
The scientists were running a continuous research
seminar on the nature, origin, and possible significance of
the radio pulses. The project's public affairs office-larger
than in most observatories because of widespread interest in
the search for extraterrestrial intelligence-was assigned
the task of filling in the lower-ranking officials. Every
new arrival required an extensive personal briefing. Ellie,
who was obliged to brief the senior officials, supervise the
ongoing research, and respond to the entirely proper
skeptical scrutiny being offered with some vigor by her
colleagues, was exhausted. The luxury of a full night's
sleep had eluded her since the discovery.
At first they had tried to keep the finding quiet.
After all, they were not absolutely sure it was an
extraterrestrial message. A premature or mistaken
announcement would be a public relations disaster. But worse
than that, it would interfere with the data analysis. If the
press descended, the science would surely suffer. Washington
as well as Argus was keen to keep the story quiet. But the
scientists had told their families, the International
Astronomical Union telegram had been sent all over the
world, and still rudimentary astronomical data-basing
systems in Europe, North America, and Japan were all
carrying news of the discovery.
Although there had been a range of contingency plans
for the public release of any findings, the actual
circumstances had caught them largely unprepared. They
drafted as innocuous a statement as they could and released
it only when they had to. It caused, of course, a sensation.
They had asked the media's forbearance, but knew
there would be only a brief period before the press would
descend in force. They had tried to discourage reporters
from visiting the site, explaining that there was no real
information in the signals they were receiving, just tedious
and repetitive prime numbers. The press was impatient with
the absence of hard news. "You can only do so many sidebars
on `What is a prime number?'" one reporter explained to
Ellie over the telephone.
Television camera crews in fixed-wing air taxis and
chartered helicopters began making low passes over the
facility, sometimes generating strong radio interference
easily detected by the telescopes. Some reporters stalked
the officials from Washington when they returned to their
motels at night. A few of the more enterprising had
attempted to enter the facility unobserved-by beach buggy,
motorcycle, and in one case on horseback. She had been
forced to inquire about bulk rates on cyclone fencing.
Immediately after der Heer arrived, he had received
an early version of what was by now Ellie's standard
briefing: the surprising intensity of the signal, its
location in very much the same part of the sky as the star
Vega, the nature of the pulses.
"I may be the President's Science Adviser," he had
said, "but I'm only a biologist. So please explain it to me
slowly. I understand that if the radio source is twenty-six
light-years away, then the message had to be sent twenty-six
years ago. In the 1960s, some funny-looking people with
pointy ears thought we'd want to know that they like prime
numbers. But prime numbers aren't difficult. It's not like
they're boasting. It's more like they're sending us remedial
arithmetic. Maybe we should be insulted."
"No, look at it this way," she said, smiling. "This
is a beacon. It's an announcement signal. It's designed to
attract our attention. We get strange patterns of pulses
from quasars and pulsars and radio galaxies and
God-knows-what. But prime numbers are very specific, very
artificial. No even number is prime, for example. It's hard
to imagine some radiating plasma or exploding galaxy sending
out a regular set of mathematical signals like this. The
prime numbers are to attract our attention."
"But what for?" he had asked, genuinely baffled.
"I don't know. But in this business you have to be
very patient. Maybe in a while the prime numbers will turn
off and be replaced by something else, something very rich,
the real message. We just have to keep on listening."
This was the hardest part to explain to the press,
that the signals had essentially no content, no meaning-just
the first few hundred prime numbers in order, a cycling back
to the beginning, and again the simple binary arithmetic
representations: 1, 2, 3, 5, 7, 11, 13, 17, 19, 23, 29,
31... Nine wasn't a prime number, she'd explain, because it
was divisible by 3 (as well as 9 and 1, of course). Ten
wasn't a prime number because 5 and 2 went into it (as well
as 10 and 1). Eleven was a prime number because it was
divisible only by 1 and itself. But why transmit prime
numbers? It reminded her of an idiot savant, one of those
people who might be grossly deficient in ordinary social or
verbal skills but who could perform mind-boggling feats of
mental arithmetic-such as figuring out, after a moment's
thought, on what day of the week June first in the year
11,977 will fall. It wasn't for anything; they did it
because they liked doing it, because they were able to do
it.
She knew it was only a few days after receipt of the
message, but she was at once exhilarated and deeply
disappointed. After all these years, they had finally
received a signal-sort of. But its content was shallow,
hollow, empty. She had imagined receiving the Encyclopedia
Galactica.
We've only achieved the capacity for radio astronomy
in the last few decades, she reminded herself, in a Galaxy
where the average star is billions of years old. The chance
of receiving a signal from a civilization exactly as
advanced as we are should be minuscule. If they were even a
little behind us, they would lack the technological
capability to communicate with us at all. So the most likely
signal would come from a civilization much more advanced.
Maybe they would be able to write full and melodic mirror
fugues: The counterpoint would be the theme written
backwards. No, she decided. While this was a kind of genius
without a doubt, and certainly beyond her ability, it was a
tiny extrapolation from what human beings could do. Bach and
Mozart had made at least respectable stabs at it.
She tried to make a bigger leap, into the mind of
someone who was enormously, orders of magnitude, more
intelligent than she was, smarter than Drumlin, say, or Eda
the young Nigerian physicist who had just won the Nobel
Prize. But it was impossible. She could muse about
demonstrating Fermat's Last Theorem or the Goldbach
Conjecture in only a few lines of equations. She could
imagine problems enormously beyond us that would be old hat
to them. But she couldn't get into their minds; she couldn't
imagine what thinking would be like if you were much more
capable than a human being. Of course. Nor surprise. What
did she expect? It was like trying to visualize a new
primary color or a world in which you could recognize
several hundred acquaintances individually only by their
smells.... She could talk about this, but she couldn't
experience it. By definition, it has to be mighty hard to
understand the behavior of a being much smarter than you
are. Buy even so, even so: Why only prime numbers?



The Argus radio astronomers had made progress in the last
few days. Vega had a known motion-a known component of its
velocity toward or away from the Earth, and a known
component laterally, across the sky, against the background
of more distant stars. The Argus telescopes, working
together with radio observatories in West Virginia and
Australia, had determined that the source was moving with
Vega. Not only was the signal coming, as carefully as they
could measure, from where Vega was in the sky; but the
signal also shared the peculiar and characteristic motions
of Vega. Unless this was a hoax of heroic proportions, the
source of the prime number pulses was indeed in the Vega
system. There was no additional Doppler effect due to the
motion of the transmitter, perhaps tied to a planet, about
Vega. The extraterrestrials had compensated for the orbital
motion. Perhaps it was a kind of interstellar courtesy.
"It's the goddamnedest most wonderful thing I ever
heard of. And it's got nothing to do with our shop," said an
official of the Defense Advanced Research Projects Agency,
preparing to return to Washington.
As soon as the discovery had been made, Ellie had
assigned a handful of the telescopes to examine Vega in a
range of other frequencies. Sure enough, they had found the
same signal, the same monotonous succession of prime
numbers, beeping away in the 1420 megahertz hydrogen line,
the 1667 megahertz hydroxyl line, and at many other
frequencies. All over the radio spectrum, with an
electromagnetic orchestra, Vega was bleating out prime
numbers.
"It doesn't make sense," said drumlin, casually
touching his belt buckle. "We couldn't have missed it
before. Everybody's looked at Vega. For years. Arroway
observed it from Arecibo a decade ago. Suddenly last Tuesday
Vega starts broadcasting prime numbers? Why now? What's so
special about now? How come they start transmitting just a
few years after Argus starts listening?"
"Maybe their transmitter was down for repairs for a
couple of centuries," Valerian suggested, "and they just got
it back on-line. maybe their duty cycle is to broadcast to
us just one year out of every million. There are all those
other candidate planets that might have life on them, you
know. We're probably not the only kid on the block." But
Drumlin, plainly dissatisfied, only shook his head.
Although his nature was the opposite of
conspiratorial, Valerian thought he had caught an
undercurrent in Drumlin's last question: could all this be a
reckless, desperate attempt by Argus scientists to prevent a
premature closing down of the project? It wasn't possible.
Valerian shook his head. As der Heer walked by, he found
himself confronted by two senior experts on the SETI problem
silently shaking their heads at one another.
Between the scientists and the bureaucrats there was
a kind of unease, a mutual discomfort, a clash of
fundamental assumptions. One of the electrical engineers
called it an impedance mismatch. The scientists were too
speculative, too quantitative, and too casual about talking
to anybody for the tastes of many of the bureaucrats. The
bureaucrats were too unimaginative, too qualitative, too
uncommunicative for many of the scientists. Ellie and
especially der Heer tried hard to bridge the gap, but the
pontoons kept being swept downstream.
This night, cigarette butts and coffee cups were
everywhere. The casually dressed scientists, Washington
officials in light-weight suits, and an occasional flag-rank
military officer filled the control room, the seminar room,
the small auditorium, and spilled out of doors, where,
illuminated by cigarettes and starlight, some of the
discussions continued. But tempers were frayed. The strain
was showing.



"Dr. Arroway, this is Michael Kitz, Assistant Secretary of
Defense for C3I."
Introducing Kitz and positioning himself just a step
behind him, der Heer was communicating... what? Some
unlikely mix of emotions. Bemusement in the arms of
prudence? He seemed to be appealing for restraint. Did he
think her such a hothead? "C3I"-pronounced
cee-cubed-eye-stood for Command, Control, Communications,
and Intelligence, important responsibilities at a time when
the United States and the Soviet Union were gamely making
major phased reductions in their strategic nuclear arsenals.
It was a job for a cautious man.
Kitz settled himself in one of the two chairs across
the desk from Ellie, leaned forward, and read the Kafka
quote. He was unimpressed.
"Dr. Arroway, let me come right to the point. We're
concerned about whether it's in the best interest of the
United States for this information to be generally known. We
were not overjoyed about your sending that telegram all over
the world."
"You mean to China? To Russia? To India?" Her voice,
despite her best effort, had a discernible edge to it. "You
wanted to keep the first 261 prime numbers secret? Do you
suppose, Mr. Kitz, the extraterrestrials intended to
communicate only with Americans? Don't you think that a
message from another civilization belongs to the whole
world?"
"You might have asked our advice."
"And risk losing the signal? Look, for all we know,
something essential, something unique might have been
broadcast after Vega had set her in New Mexico but when it
was high in the sky over Beijing. These signals aren't
exactly a person-to-person call to the U.S. of A. They're
not even a person-to-person call to the Earth. It's
station-to-station to any planet in the solar system. We
just happened to be lucky enough to pick up the phone."
Der Heer was radiating something again. What was he
trying to tell her? That he liked that elementary analogy,
but ease up on Kitz?
"In any case," she continued, "it's too late.
Everybody knows now that there's some kind of intelligent
life in the Vega system."
"I'm not sure it's too late, Dr. Arroway. You seem
to think there'll be some information-rich transmission, a
message, still to come. Dr. der Heer here"-he paused to
listen to the unexpected assonance-"Dr. der Heer says you
think these prime numbers are an announcement, something to
make us pay attention. If there is a message and it's
subtle-something those other countries wouldn't pick up
right away-I want it kept quiet until we can talk about it."
"Many of us have wants, Mr. Kitz, she found herself
saying sweetly, ignoring der Heer's raised eyebrows. There
was something irritating, almost provocative, about Kitz's
manner. And probably hers as well. "I, for example, have a
want to understand what the meaning of this signal is, and
what's happening on Vega, and what it means for the Earth.
It's possible that scientists in other nations are the key
to that understanding. Maybe we'll need their data. Maybe
we'll need their brains. I could imagine this might be a
problem too big for one country to handle all by itself."
Der Heer now appeared faintly alarmed. "Uh, Dr.
Arroway. Secretary Kitz's suggestion isn't all that
unreasonable. It's very possible we'd bring other nations
in. All he's asking is to talk about it with us first. And
that's only if there's a new message."
His tone was calming but not unctuous. She looked at
him closely again. Der Heer was not a patently handsome man,
but he had a kind and intelligent face. He was wearing a
blue suit and a crisp oxford shirt. His seriousness and air
of self-possession were moderated by the warmth of his
smile. Why, then, was he shilling for this jerk? Part of his
job? Could it be that Kitz was talking sense?
"It's a remote contingency anyway." Kitz sighed as
he got to his feet. "The Secretary of Defense would
appreciate your cooperation." He was trying to be winning.
"Agreed?"
"Let me think about it," she replied, taking his
proffered hand as if it were a dead fish.
"I'll be along in a few minutes, Mike," der Heer
said cheerfully.
His hand on the lintel of the door, Kitz had an
apparent afterthought, removed a document from his inside
breast pocket, returned, and placed it gingerly on the
corner of her desk. "Oh yes, I forgot. Here's a copy of the
Hadden Decision. You probably know it. It's about the
government's right to classify material vital to the
security of the United States. Even if it didn't originate
in a classified facility."
"You want to classify the prime numbers?" she asked,
her eyes wide in mock incredulity.
"See you outside, Ken."
She began talking the moment Kitz left her office.
"What's he after? Vegan death rays? World blower-uppers?
What's this really about?"
"He's just being prudent, Ellie. I can see you don't
think that's the whole story. Okay. Suppose there's some
message-you know, with real content-and in it there's
something offensive to Muslims, say, or to Methodists.
Shouldn't we release it carefully, so the United States
doesn't get a black eye?"
"Ken, don't bullshit me. That man is an Assistant
Secretary of Defense. If they're worried about Muslims and
Methodists, they would have sent me an Assistant Secretary
of State, or-I don't know-one of those religious fanatics
who preside at presidential prayer breakfasts. You're the
President's Science Adviser. What did you advise her?"
"I haven't advised her anything. Since I've been
here, I've only talked to her once, briefly, on the phone.
And I'll be frank with you, she didn't give me any
instructions about classification. I thought what Kitz said
was way off base. I think he's acting on his own."
"Who is he?"
"As far as I know, he's a lawyer. He was a top
executive in the electronics industry before joining the
Administration. He really knows C3I, but that doesn't make
him knowledgeable about anything else."
"Ken, I trust you. I believe you didn't set me up
for this Hadden Decision threat." She waved the document in
front of her and paused, seeking his eyes. "Do you know that
Drumlin thinks there's another message in the polarization?"
"I don't understand."
"Just a few hours ago, Dave finished a rough
statistical study of the polarization. He's represented the
Stokes parameters by Poin-car� spheres; there's a nice movie
of them varying in time."
Der Heer looked at her blankly. Don't biologists use
polarized light in their microscopes? she asked herself.
"When a wave of light comes at you-visible light,
radio light, any kind of light-it's vibrating at right
angles to your line of sight. If that vibration rotates, the
wave is said to be elliptically polarized. If it rotates
clockwise, the polarization is called right-handed;
counterclockwise, it's left-handed. I know it's a dumb
designation. Anyway, by varying between the two kinds of
polarization, you could transmit information. A little right
polarization and that's a zero; a little left and it's a
one. Follow? It's perfectly possible. We have amplitude
modulation and frequency modulation, but our civilization,
by convention, ordinarily just doesn't do polarization
modulation.
"Well, the Vega signal looks as if it has
polarization modulating. We're busy checking it out right
now. But Dave found that there wasn't an equal amount of the
two sorts of polarization. It wasn't left polarized as much
as it was right polarized. It's just possible that there's
another message in the polarization that we've missed so
far. That's why I'm suspicious about your friend. Kitz isn't
just giving me general gratuitous advice. He knows we may be
onto something else."
"Ellie, take it easy. You've hardly slept for four
days. You've been juggling the science, the administration,
and the press. You've already made one of the major
discoveries of the century, and if I understand you right,
you might be on the verge of something even more important.
You've got every right to be a little on edge. And
threatening to militarize the project was clumsy of Kitz. I
don't have any trouble understanding why you're suspicious
of him. But there's some sense to what he says."
"Do you know the man?"
"I've been in a few meetings with him. I can hardly
say I know him. Ellie, if there's a possibility of a real
message coming in, wouldn't it be a good idea to thin out
the crowd a little?"
"Sure. Give me a hand with some of the Washington
deadwood."
"Okay. And if you leave that document on your desk,
someone'll be in here and draw the wrong conclusion. Why
don't you put it away somewhere?"
"You're going to help?"
"If the situation stays anything like what it is
now, I'll help. We're not going to make our best effort if
this thing gets classified."
Smiling, Ellie knelt before her small office safe,
and punched in the six-digit combination, 314159. She took
one last glance at the document that was titled in large
black letters the united states vs. hadden cybernetics, and
locked it away.



It was a group of about thirty people-technicians and
scientists associated with Project Argus, a few senior
government officials, including the Deputy Director of the
Defense Intelligence Agency in civilian clothes. Among them
were Valerian, Drumlin, Kitz, and der Heer. Ellie was the
only woman. They had set up a large television projection
system, focused on a two-meter-by-two-meter screen set flush
against the far wall. Ellie was simultaneously addressing
the group and the decryption program, her fingers on the
keyboard before her.
"Over the years we've prepared for the computer
decryption of many kinds of possible messages. We've just
learned from Dr. Drumlin's analysis that there's information
in the polarization modulation. All that frenetic switching
between left and right means something. It's not random
noise. It's as if you're flipping a coin. Of course, you
expect as many heads as tails, but instead you get twice as
many heads as tails. so you conclude that the coin is loaded
or, in our case, that the polarization modulation isn't
random; it has content.... Oh, look at this. What the
computer has just now told us is even more interesting. The
precise sequence of heads and tails repeats. It's a long
sequence, so it's a pretty complex message, and the
transmitting civilization must want us to be sure to get it
right.
"Here, you see? This is the repeating message. We're
now into the first repetition. Every bit of information,
every dot and dash-if you want to think of them that way-is
identical to what it was in the last block of data. Now we
analyze the total number of buts. It's a number in the tens
of billions. Okay, bingo! It's the product of three prime
numbers."
Although Drumlin and Valerian were both beaming, it
seemed to Ellie they were experiencing quite different
emotions.
"So what? What do some more prime numbers mean?" a
visitor from Washington asked.
"It means-maybe-that we're being sent a picture. You
see, this message is made of a large number of bits of
information. Suppose that large number is the product of
three smaller numbers; it's a number times a number times a
number. So there's three dimensions to the message. I'd
guess either it's a single static three-dimensional picture
like a stationary hologram, or it's a two-dimensional
picture that changes with time-a movie. Let's assume it's a
movie. If it's a hologram, it'll take us longer to display
anyway. We've got an ideal decryption algorithm for this
one."
On the screen, they made out an indistinct moving
pattern composed of perfect whites and perfect blacks.
"Willie, put in some gray interpolation program,
would you? Anything reasonable. And try rotating it about
ninety degrees counterclockwise."
"Dr. Arroway, there seems to be an auxiliary
sideband channel. Maybe it's the audio to go with the
movie."
"Punch it up."
The only other practical application of prime
numbers she could think of was public-key cryptography, now
widely used in commercial and national security contexts.
One application was to make a message clear to dummies; the
other was to keep a message hidden from the tolerably
intelligent.
Ellie scanned the faces before her. Kitz looked
uncomfortable. Perhaps he was anticipation some alien
invader or, worse, the design drawings of a weapon too
secret for her staff to be trusted with. Willie looked very
earnest and was swallowing over and over again. A picture is
different from mere numbers. The possibility of a visual
message was clearly rousing unexamined fears and fantasies
in the hearts of many of the onlookers. Der Heer had a
wonderful expression on his face; for the moment he seemed
much less the official, the bureaucrat, the presidential
adviser, and much more the scientist.
The picture, still unintelligible, was joined by a
deep rumbling glissando of sounds, sliding first up and then
down the audio spectrum until it gravitated to rest
somewhere around the octave below middle C. Slowly the group
became aware of faint but swelling music. The picture
rotated, rectified, and focused.
Ellie found herself staring at a black-and-white
grainy image of... a massive reviewing stand adorned with an
immense art deco eagle. Clutched in the eagle's concrete
talons...
"Hoax! It's a hoax!" There were cries of
astonishment, incredulity, laughter, mild hysteria.
"Don't you see? You've been hoodwinked," Drumlin was
saying to her almost conversationally. He was smiling. "It's
an elaborate practical joke. You've been wasting the time of
everybody here."
Clutched in the eagle's concrete talons, she could
now see clearly, was a swastika. The camera zoomed in above
the eagle to find the smiling face of Adolf Hitler, waving
to a rhythmically chanting crowd. His uniform, devoid of
military decorations, conveyed a modest simplicity. The deep
baritone voice of an announcer, scratchy but unmistakably
speaking German, filled the room. Der Heer moved toward her.
"Do you know German?" she whispered. "What's it
saying?"
"The Fuehrer," he translated slowly, "welcomes the
world to the German Fatherland for the opening of the 1936
Olympic Games."

--
... In 2345, on the 10th anniversary of the Shivan attack
on Ross 128, the Vasudan emperor Khonsu II addressed the
newly formed GTVA General Assembly. The emperor inaugurated
an ambiguous and unprecedented joint endeavor: the GTVA
Colossus...

※ 来源:．The unknown SPACE bbs.mit.edu．[FROM: 204.91.54.100]

--

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☆ 来源:．哈工大紫丁香 bbs.hit.edu.cn．[FROM: baohf.bbs@smth.org]

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