Rama 2 by Arthur C. Clarke and Gentry Lee

General O’Toole waved his arms at the large cavern around him. “There must be some reason, some grand plan for all this. Why were all those fake human objects left in the White Room? Why did the Ramans invite us to communicate with them? Who and what are the avians and the octospiders?” He shook his head, frustrated by all the unanswered questions. “I was uncertain about destroying Rama; but I’m equally uncertain about sending the warning. What if Rama escapes the nuclear attack because of us and then destroys the Earth anyway?”

“That’s extremely unlikely, Michael. The first Rama sailed through the solar system—”

“Just a minute, Nicole, if you don’t mind,” Richard interrupted softly. “Let me try to answer the general.”

He walked over and put his arm on General O’Toole’s shoulder. “Mi­chael,” Richard said, “what has impressed me the most about you since the first time we met has been your ability to understand the difference between the answers we can know, as a result of deduction or the scientific method, and those questions for which there is not even a valid logical approach. There is no way whatsoever that we can understand what Rama is all about at this juncture. We don’t yet have enough data. It’s like trying to solve a system of simultaneous linear equations when there are many more variables than constraints. Multiple hypersurfaces of correct solutions exist.”

O’Toole smiled and nodded his head. “What we do know/’ Richard con­tinued, “is that a fleet of missiles is now approaching Rama. They are proba­bly armed with nuclear warheads. We have a choice, to warn or not to warn, and we must make it based on the information available to us at this mo­ment.”

Richard pulled out his small computer and walked over beside O’Toole. “You can represent this entire problem as a three-by-two matrix,” he said. “Assume there are three possible descriptions of the Raman threat; never hostile, always hostile, and hostile only if attacked. Let these three situations represent the rows of the matrix. Now consider the decision facing us. We can either warn them, or choose not to. Note that it is only a successful warning that matters. So there are two columns to the matrix, Rama warned and Rama not warned.”

O’Toole and Nicole both looked over Richard’s shoulder as he constructed the matrix and displayed it on his small monitor. “If we now look at the outcomes of the six events represented by the individual elements in this matrix, and try to assign some probabilities wherever we can, we will have all the information we need to make our decision. Do you agree?”

General O’Toole nodded, impressed by how quickly and concisely Richard had structured their dilemma. “The outcome of the second row is always the same,” Nicole now offered, “independent of whether or not we warn them. If Rama is truly hostile, with their more advanced technology it makes no difference whether we warn them or not. Sooner or later, with this vehicle or one that comes in the future, they will either subjugate or destroy the human race.”

Richard paused a moment to ensure that O’Toole was following the conversation, “Similarly,” he then said slowly, “if Rama is never hostile, it can­not be wrong to warn them. In neither case, warned or unwarned, is the Earth in danger. And if we are successful in telling them about the nuclear missiles, then something extraordinary will have been saved.”

The general smiled. “So the only possible problem, O’Toole’s Anxiety, if you want to call it that, comes if Rama was not originally intending to be hostile, but will change its mind and attack the Earth once it learns that nuclear missiles have been launched against it.”

“Precisely,” said Richard. “And I would argue that our warning itself would probably be a mitigating factor in that potentially hostile case. After all—”

“All right. AD right,” O’Toole replied. “I see where you’re headed. Unless a very high probability is assigned to the case I’m worried about, the overall analysis suggests a better result from warning the Ramans.” He suddenly laughed. “It’s a good thing you don’t work for COG military headquarters, Richard. You might have convinced me with logic to activate the code—”

“I doubt it,” Nicole said. “Nobody could have made a solid case for that kind of paranoia.”

“Thank you.” The general smiled. “I’m satisfied. You were very persua­sive. Let’s go back to work.”

Driven by the relentless approach of the missiles, the threesome worked tirelessly for hours. Nicole and Michael O’Toole designed the warning mes­sage in two discrete segments. The first segment, much of which was back­ground to establish the basic communication technique, presented all the trajectory mechanics, including the Rama orbit as the vehicle entered the solar system, the two Newton craft leaving the Earth and joining just before rendezvous with the alien ship, the two Raman maneuvers changing its trajectory, and finally the sixteen missiles blasting off from the Earth toward a Rama intercept. Richard, his long hours of work at the keyboard and black screen now paying off, transformed all these orbital events into graphic line drawings while the other two cosmonauts struggled with the complexity of the remainder of the message.

The second segment was exceedingly difficult to design. In it the humans wanted to explain that the incoming missiles carried nuclear warheads, that the explosive power of the bombs was generated by a chain reaction, and that the heat, shock, and radiation resulting from the explosion were all enormously powerful. Presenting the fundamental picture was not the chal­lenge; quantifying the destructive power in any terms that could be under­stood by an extraterrestrial intelligence was a formidable obstacle.

“It’s impossible,” an exasperated Richard exclaimed when both O’Toole and Nicole insisted that the warning was not complete without some indica­tion of the explosion temperature and the magnitude of the shock and radia­tion fields. “Why don’t we just indicate the quantity of fissionable material in the process? They must be great at physics. They can compute the yield and other parameters.”

Time was running out and all three of them were becoming exhausted. In the final hours, General O’Toole succumbed to fatigue and, at Nicole’s insis­tence, took a substantial nap. His biometry output had indicated that his heart was in stress. Richard even slept for ninety minutes. But Nicole never allowed herself the luxury of rest. She was determined to figure out some way to depict in pictures the destructive power of the weapons.

When the men awakened, Nicole convinced them to append to the sec­ond segment an additional short section demonstrating what would happen to a city or forest on Earth if a one-megaton nuclear bomb exploded in the vicinity. For these pictures to make any sense, of course, Richard had to expand his earlier glossary, in which he had defined the chemical elements and their symbols with mathematical precision, to include some more mea­sures of size. “If they understand this,” he grumbled as he laboriously in­cluded scale tick marks beside his line drawings of buildings and trees, “then they’re smarter than even I gave them credit for.”

Finally the message was completed and stored. They reviewed the entire warning one last time and made a few corrections. “Of the commands that I have never been able to understand/’ Richard said, “there are five that I have reason to suspect may be links to a different level processor. Of course, I am only guessing, but I believe it’s an educated guess. I will transmit our message five times, using each of these particular commands a single time, and hope that our warning somehow reaches the central computer.”

While Richard entered all the proper commands into the keyboard, Ni­cole and General O’Toole went for a walk. They climbed up the stairway and wandered around the skyscrapers of New York. “You believe that we were meant to board Rama and find the White Room, don’t you?”

“Yes,” Nicole answered.

“But for what purpose?” asked the general. “If the Ramans just wanted to make contact with us, why did they go to such elaborate lengths? And why are they risking our misinterpretation of their intent?”

“I don’t know,” Nicole said. “Maybe they’re testing us in some way. To find out what we’re like.”

“Goodness,” O’Toole replied, “what a terrible thought. We may be cata­logued as the creatures who launch nuclear attacks against visitors.”

“Exactly,” said Nicole.

Nicole showed O’Toole the bam with the pits, the lattice where she had rescued the avian, the stunning polyhedrons, and the entrances to the other two lairs. She was becoming very tired, but she knew that she would not sleep until everything was resolved.

“Should we head back?” O’Toole said after he and Nicole had walked down to the Cylindrical Sea and verified that the sailboat was still intact where they had left it.

“All right,” Nicole answered wearily. She checked her watch. It was ex­actly three hours and eighteen minutes until the first nuclear missile would arrive at Rama.