Free Factoring Humanity by Robert J. Sawyer Page A

at a group of frequencies called “the water hole”—between the emission frequency for hydrogen, at 1420 megahertz, and for hydroxyl, at 1667 megahertz. Hydrogen (H) and hydroxyl (OH) are the components of water (H 2 0), and Earth’s atmosphere is most transparent to radio waves at that range of frequencies, while interstellar space is largely free of interference there. Since all life as we know it began in water, this area of the spectrum seemed a natural gathering place for those species looking to undertake interstellar communications.
    But the Centauri signals weren’t anywhere near the water hole—another example of what we expected to be a shared view of reality not turning out to be shared at all.
    Could there, Heather wondered, be other water holes—other common grounds that would have to be shared by any being that existed in the same universe we did, regardless of its biology or the nature of its planet?
    She was supposed to meet her friend Judy for lunch at the Faculty Club at 12:15. She’d stick around until today’s message began to arrive, then head off.
    Still ten minutes to go. Heather wasn’t one to waste time. She had the latest issue of The Journal of Jungian Studies on her datapad; she started working her way through it.
    After a while, the phone rang. Heather finished the paragraph in front of her, then absently reached for the handset. “Hello?”
    “Heather? Did you forget?”
    Heather glanced at her watch. “Oh, God! Sorry, Judy!” She looked over at her computer. “I was waiting for today’s message—I was going to leave as soon as the incoming-message signal sounded.” She moved over to her computer and told it to go directly to the Alien Signal Center homepage. Nothing.
    “Judy, I can’t make it. The alien message is late today.”
    “Are you sure you’ve got the right time?”
    “Positive. Look, I’ve got to go. Maybe lunch tomorrow?”
    “Sure, I’ll call you.”
    “Thanks.” Heather replaced the handset. As soon as she did, the phone rang again. She picked it up. “Hello?”
    “Heather,” said a different female voice, “it’s Salme van Horne.”
    “Salme! Where are you? Here in Canada?”
    “No, I’m still in Helsinki. Have you tried to download today’s message?”
    “Yes. There doesn’t seem to be one coming through.”
    “This has never happened before, has it? The Centaurs have never missed a day, have they?”
    “Never. They’ve never even been late.”
    “Do you suppose the problem is at our end?” asked Salme. “Whose turn is it to receive the message?”
    “Arecibo is designated prime, isn’t it? But there are backups, and—oh, wait. Something’s going up on the Web page.”
    “I see it, too.”
    “Damn holograms—ah, here it is: ‘No technical malfunction at receiving end. Apparently no message was sent.’ ”
    “That can’t be the end of the transmissions,” said Salme. “There has to be a key.”
    “Maybe they got tired of waiting for us to reply,” said Heather. “Maybe they won’t send again until we do reply.”
    “Or maybe—”
    “What?” asked Heather.
    “Drake equation, final term.”
    Heather was quiet for a moment. “Oh,” she said softly.
    The Drake equation estimated the number of radio-broadcasting civilizations in the galaxy. It had seven terms:
     
    R * f p n e f l f i f c L
     
    The rate of star formation, times the fraction of stars with planets, times the number of those planets that are suitable for life, times the fraction of such planets on which life actually appears, times the fraction of life forms that are intelligent, times the fraction of such life forms that actually develop radio, times . . .
    Times big L: the lifetime of such a civilization.
    A civilization that had radio probably also had nuclear weapons, or other equally dangerous things.
    Civilizations could be wiped out in a matter of moments—certainly in less than a single thirty-one-hour day.
    “They can’t be dead,” said