«No message,» I said.
Rizzo shrugged elaborately.
«If you leave the ’scope on for two days, you’ll find that the line makes a full swing from peak to null,» I informed him. «The star pulsates every two days, bright to dim.»
«Let’s turn up the gain,» he said, and he flicked a few knobs on the front of the ’scope.
The line didn’t change at all. «What’s the sweep speed?» I asked.
«One nanosecond per centimeter.» That meant that each centimeter-wide square on the screen’s face represented one billionth of a second. There are as many nanoseconds in one second as there are seconds in thirty-two years.
«Well, if you don’t get a signal at that sensitivity, there just isn’t any signal there,» I said.
Rizzo nodded. He seemed slightly disappointed that his joke was at an end. I turned back to the meteorological instruments, but I couldn’t concentrate on them. Somehow I felt disappointed, too. Subconsciously, I suppose, I had been hoping that Rizzo actually would detect a signal from the star. Fool! I told myself. But what could explain that bright emission line? I glanced up at the oscilloscope again.
And suddenly the smooth steady line broke into a jagged series of millions of peaks and nulls!
I stared at it.
Rizzo was back on his bunk again, reading one of his magazines. I tried to call him, but the words froze in my throat. Without taking my eyes from the flickering ’scope, I reached out and touched his arm.
He looked up.
«Holy Mother of God,» Rizzo whispered.
For a long time we stared silently at the fluttering line dancing across the oscilloscope screen, bathing our tiny dome in its weird greenish light. It was eerily fascinating, hypnotic. The line never stood still; it jabbered and stuttered, a series of millions of little peaks and nulls, changing almost too fast for the eye to follow, up and down, calling to us, speaking to us, up, down, never still, never quiet, constantly flickering its unknown message to us.
«Can it be … people?» Rizzo wondered. His face, bathed in the greenish light, was suddenly furrowed, withered, ancient: a mixture of disbelief and fear.
«What else could it be?» I heard my own voice answer. «There’s no other explanation possible.»
We sat mutely for God knows how long.
Finally Rizzo asked, «What do we do now?»
The question broke our entranced mood. What do we do? What action do we take? We’re thinking men, and we’ve been contacted by other creatures that can think, reason, send a signal across seven hundred lightyears of space. So don’t just sit there in stupified awe. Use you’re brain, prove that you’re worthy of the tag sapiens.
«We decode the message,» I announced. Then, as an after thought, «But don’t ask me how.» We should have called McMurdo, or Washington. Or perhaps we should have attempted to get a message through to the United Nations. But we never even thought of it. This was our problem. Perhaps it was the sheer isolation of our dome that kept us from thinking about the rest of the world. Perhaps it was sheer luck.
«If they’re using lasers,» Rizzo reasoned, «they must have a technology something like ours.»
«Must have had,» I corrected. «That message is seven hundred years old, remember. They were playing with lasers when King John was signing the Magna Charta and Genghis Khan owned most of Asia. Lord knows what they have now.»
Rizzo blanched and reached for another cigaret.
I turned back to the oscilloscope. The signal was still flashing across its face.
«They’re sending out a signal,» I mused, «probably at random. Just beaming it out into space, hoping that someone, somewhere will pick it up. It must be in some form of code … but a code that they feel can be easily cracked by anyone with enough intelligence to realize that there’s a message there.»
«Sort of an interstellar Morse code.»
I shook my head. «Morse code depends on both sides knowing the code. There’s no key.»
«Cryptographers crack codes.»
«Sure. If they know what language is being used. We don’t know the language, we don’t know the alphabet, the thought processes … nothing.»
«But it’s a code that can be cracked easily,» Rizzo muttered.
«Yes,» I agreed. «Now what the hell kind of a code can they assume will be known to another race that they’ve never seen?»
Rizzo leaned back on his bunk and his face was lost in shadows.
«An interstellar code,» I rambled on. «Some form of presenting information that would be known to almost any race intelligent enough to understand lasers …»
«Binary!» Rizzo snapped, sitting up on the bunk.
«What?»
«Binary code. To send a signal like this, they’ve gotta be able to write a message in units that’re only a billionth of a second long. That takes computers. Right? Well, if they have computers, they must figure that we have computers. Digital computers run on binary code. Off or on … go or no-go. It’s simple. I’ll bet we can slap that signal on a tape and run it through our computer here.»
«To assume that they use computers exactly like ours.»
«Maybe the computers are completely different,» Rizzo said excitedly, «but the binary code is basic to them all. I’ll bet on that! And this computer we’ve got here—this transistorized baby—she can handle more information than the whole Army could feed into her. I’ll bet nothing has been developed anywhere that’s better for handling simple one-plus-one types of operations.»
I shrugged. «All right. It’s worth a trial.»
It took Rizzo a few hours to get everything properly set up. I did some arithmetic while he worked. If the message was in binary code, that meant that every cycle of the signal—every flick of the dancing line on our screen—carried a bit of information. The signal’s wavelength was 5000 Angstroms; there are a hundred million Angstrom units to the centimeter; figuring the speed of light … the signal could carry, in theory at least, something like 600 trillion bits of information per second.
I told Rizzo.
«Yeah, I know. I’ve been going over the same numbers in my head.» He set a few switches on the computer control board. «Now let’s see how many of the 600 trillion we can pick up.» He sat down before the board and pressed a series of buttons.
We watched, hardly breathing, as the computer’s spools began spinning and the indicator lights flashed across the control board. Within a few minutes, the printer chugged to life.
Rizzo swivelled his chair over to the printer and held up the unrolling sheet in a trembling hand.
Numbers. Six digit numbers. Completely meaningless.
«Gibberish,» Rizzo snapped.
It was peculiar. I felt relieved and disappointed at the same time.
«Something’s screwy,» Rizzo said. «Maybe I fouled up the circuits …»
«I don’t think so,» I answered. «After all, what did you expect out of the computer? Shakespearean poetry?»
«No, but I expected numbers that would make some sense. One and one, maybe. Something that means something. This stuff is nowhere.»
Our nerves must have really been wound tight, because before we knew it we were in the middle of a nasty argument—and it was over nothing, really. But in the middle of it:
«Hey, look,» Rizzo shouted, pointing to the oscilloscope.
The message had stopped. The ’scope showed only the calm, steady line of the star’s basic two-day-long pulsation.
It suddenly occurred to us that we hadn’t slept for more than 36 hours, and we were both exhausted. We forgot the senseless argument. The message was ended. Perhaps there would be another; perhaps not. We had the telescope, spectrometer, photocell, oscilloscope, and computer set to record automatically. We collapsed into our bunks. I suppose I should have had monumental dreams. I didn’t. I slept like a dead man.