Part 2

"Why is the hydrogen weight 1.008?" Before Rizzo could answer, I went on, "For two reasons. The system we use arbitrarily rates oxygen as 16-even. Right? All the other weights are calculated from oxygen's. And we also give the average weight of an element, counting all its isotopes. Our weight for hydrogen also includes an adjustment for tiny amounts of deuterium and tritium. Right? Well, suppose _they_ have a system that rates hydrogen as a flat one: 1.00000. Doesn't _that_ make sense?"

"You're getting punchy," Rizzo grumbled. "What about the isotopes? How can they expect us to handle decimal points if they don't tell us about them ... mental telepathy? What about...."

"Stop arguing and start calculating," I snapped. "Change that list of numbers to agree with our periodic table. Change 1.00000 to 1.008-whatever-it-is and tackle the next few elements. The decimals shouldn't be so hard to figure out."

Rizzo grumbled to himself, but started working out the calculations. I stepped over to the dome's microspool library and found an elementary physics text. Within a few minutes, Rizzo had some numbers and I had the periodic table focused on the microspool reading machine.

"Nothing," Rizzo said, leaning over my shoulder and looking at the screen. "They don't match at all."

"Try another list. They're not all the same."

He shrugged and returned to his desk. After a while he called out, "their second number is 3.97123; it works out to 4.003-something."

It checked! "Good. That's helium. What about the next one, lithium?"

"That's 6.940."

"Right!"

Rizzo went to work furiously after that. I pushed a chair to the desk and began working up from the end of the list. It all checked out, from hydrogen to a few elements beyond the artificial ones that had been created in the laboratories here on Earth.

"That's it," I said. "That's the key. That's our Rosetta Stone ... the periodic table."

Rizzo stared at the scribbled numbers and jumble of papers. "I bet I know what the other lists are ... the ones that don't make sense."

"Oh?"

"There are other ways to identify the elements ... vibration resonances, quantum wavelengths ... somebody named Lewis came out a couple years ago with a Quantum Periodic Table...."

"They're covering all the possibilities. There are messages for many different levels of understanding. We just decoded the simplest one."

"Yeah."

I noticed that as he spoke, Rizzo's hand--still tightly clutching the pencil--was trembling and white with tension.

"Well?"

Rizzo licked his lips. "Let's get to work."

* * * * *

We were like two men possessed. Eating, sleeping, even talking was ignored completely as we waded through the hundreds of sheets of paper. We could decode only a small percentage of them, but they still represented many hours of communication. The sheets that we couldn't decode, we suspected, were repetitions of the same message that we were working on.

We lost all concept of time. We must have slept, more than once, but I simply don't remember. All I can recall is thousands of numbers, row upon row, sheet after sheet of numbers ... and my pencil scratching symbols of the various chemical elements over them until my hand was so cramped I could no longer open the fingers.

The message consisted of a long series of formulas; that much was certain. But, without punctuation, with no knowledge of the symbols that denote even such simple things as "plus" or "equals" or "yields," it took us more weeks of hard work to unravel the sense of each equation. And even then, there was more to the message than met the eye:

"Just what the hell are they driving at?" Rizzo wondered aloud. His face had changed: it was thinner, hollow-eyed, weary, covered with a scraggly beard.

"Then you think there's a meaning behind all these equations, too?"

He nodded. "It's a message, not just a contact. They're going to an awful lot of trouble to beam out this message, and they're repeating it every seven hours. They haven't added anything new in the weeks we've been watching."

"I wonder how many years or centuries they've been sending out this message, waiting for someone to pick it up, looking for someone to answer them."

"Maybe we should call Washington...."

"No!"

Rizzo grinned. "Afraid of breaking radio silence?"

"Hell no. I just want to wait until we're relieved, so we can make this announcement in person. I'm not going to let some old wheezer in Washington get credit for this.... Besides, I want to know just what they're trying to tell us."

It was agonizing, painstaking work. Most of the formulas meant nothing to either one of us. We had to ransack the dome's meager library of microspools to piece them together. They started simply enough--basic chemical combinations: carbon and two oxygens yield CO_{2}; two hydrogens and oxygen give water. A primer ... not of words, but of equations.

The equations became steadily longer and more complex. Then, abruptly, they simplified, only to begin a new deepening, simplify again, and finally become very complicated just at the end. The last few lines were obviously repetitious.

Gradually, their meaning became clear to us.

The first set of equations started off with simple, naturally-occurring energy yielding formulas. The oxidation of cellulose (we found the formula for that in an organic chemistry text left behind by one of the dome's previous occupants), which probably referred to the burning of plants and vegetation. A string of formulas that had groupings in them that I dimly recognized as amino acids--no doubt something to do with digesting food. There were many others, including a few that Rizzo claimed had the expression for chlorophyll in them.

"Naturally-occurring, energy-yielding reactions," Rizzo summarized. "They're probably trying to describe the biological set-up on their planet."

It seemed an inspired guess.

* * * * *

The second set of equations again began with simple formulas. The cellulose-burning reaction appeared again, but this time it was followed by equations dealing with the oxidation of hydrocarbons: coal and oil burning? A long series of equations that bore repeatedly the symbols for many different metals came up next, followed by more on hydrocarbons, and then a string of formulas that we couldn't decipher at all.

This time it was my guess: "These look like energy-yielding reactions, too. At least in the beginning. But they don't seem to be naturally occurring types. Then comes a long story about metals. They're trying to tell us the history of their technological development--burning wood, coal and eventually oil; smelting metals ... they're showing us how they developed their technology."

The final set of equations began with an ominous simplicity: a short series of very brief symbols that had the net result of four hydrogen atoms building into a helium atom. Nuclear fusion.

"That's the proton-proton reaction," I explained to Rizzo. "The type of fusion that goes on in the Sun."

The next series of equations spelled out the more complex carbon-nitrogen cycle of nuclear fusion, which was probably the primary energy source of their own Cepheid variable star. Then came a long series of equations that we couldn't decode in detail, but the symbols for uranium and plutonium, and some of the heavier elements, kept cropping up.

Then came one line that told us the whole story: the lithium-hydride equation--nuclear fusion bombs.

The equations went on to more complex reactions, formulas that no man on Earth had ever seen before. They were showing us the summation of their knowledge, and they had obviously been dealing with nuclear energies for much longer than we have on Earth.

But interspersed among the new equations, they repeated a set of formulas that always began with the lithium-hydride fusion reaction. The message ended in a way that wrenched my stomach: the fusion bomb reaction and its cohorts were repeated ten straight times.

* * * * *

I'm not sure of what day it was on the calendar, but the clock on the master control console said it was well past eleven.

Rizzo rubbed a weary hand across his eyes. "Well, what do you think?"

"It's pretty obvious," I said. "They have the bombs. They've had them for quite some time. They must have a lot of other weapons, too--more ... advanced. They're trying to tell us their history with the equations. First they depended on natural sources of energy, plants and animals; then they developed artificial energy sources and built up a technology; finally they discovered nuclear energy."

"How long do you think they've had the bombs?"

"Hard to tell. A generation ... a century. What difference does it make? They have them. They probably thought, at first, that they could learn to live with them ... but imagine what it must be like to have those weapons at your fingertips ... for a century. Forever. Now they're so scared of them that they're beaming their whole history out into space, looking for someone to tell them how to live with the bombs, how to avoid using them."

"You could be wrong," Rizzo said. "They could be boasting about their arsenal."

"Why? For what reason? No ... the way they keep repeating those last equations. They're pleading for help."

Rizzo turned to the oscilloscope. It was flickering again.

"Think it's the same thing?"

"No doubt. You're taping it anyway, aren't you?"

"Yeah, sure. Automatically."

Suddenly, in mid-flight, the signal winked off. The pulsations didn't simply smooth out into a steady line, as they had before. The screen simply went dead.

"That's funny," Rizzo said, puzzled. He checked the oscilloscope. "Nothing wrong here. Something must've happened to the telescope."

Suddenly I knew what had happened. "Take the spectrometer off and turn on the image-amplifier," I told him.

I knew what we would see. I knew why the oscilloscope beam had suddenly gone off scale. And the knowledge was making me sick.

Rizzo removed the spectrometer set-up and flicked the switch that energized the image-amplifier's viewscreen.

"Holy God!"

The dome was flooded with light. The star had exploded.

"They had the bombs all right," I heard myself saying. "And they couldn't prevent themselves from using them. And they had a lot more, too. Enough to push their star past its natural limits."

Rizzo's face was etched in the harsh light.

"I've gotta get out of here," he muttered, looking all around the cramped dome. "I've gotta get back to my wife and find someplace where it's safe...."

"Someplace?" I asked, staring at the screen. "Where?"

THE END