Contact - Carl Sagan [30]
"Finally, what's being sent seems to be a long sequence of prime numbers, integers that can't be divided by any other number except themselves and one. No astrophysical process is likely to generate prime numbers. So I'd say-we want to be cautious, of course-but I'd say that by every criterion we can lay our hands on, this looks like the real thing.
"But there's a problem with the idea that this is a message from guys who evolved on some planet around Vega, because they would have had to evolve very fast. The entire lifetime of the star is only about four hundred million years. It's an unlikely place for the nearest civilization. So the proper motion study is very important. But I sure would like to check out that hoax possibility some more."
"Look," said one of the quasar survey astronomers who had been hovering in the back. He inclined his jaw to the western horizon where a faint pink aura showed unmistakably where the Sun had set. "Vega is going to set in another couple of hours. It's probably already risen in Australia. Can't we call Sydney and get them looking at the same time that we're still seeing it?"
"Good idea. It's only middle afternoon there. And together we'll have enough baseline for the proper motion study. Give me that summary printout, and I'll telefax it to Australia from my office."
With deliberate composure, Ellie left the assembled group crowded around the consoles and returned to her office. She closed the door very carefully behind her.
"Holy shit!" she whispered.
* * *
"Ian Broderick, please. Yes. This is Eleanor Arroway at Project Argus. It's something of an emergency. Thanks, I'll hold on… Hello, Ian? It's probably nothing, but we have a bogey here and wonder if you could just check it out for us. It's around nine gigahertz, with a few hundred hertz bandpass. I'm telefaxing the parameters now… You have a feed good at nine gigahertz already on the dish? That's a bit of luck… Yes, Vega is smack in the middle of the field of view. And we're getting what looks like prime number pulses… Really. Okay, I'll hold on."
She considered again how backward the world astronomical community still was. A joint computer data-basing system was still not on-line. Its value for asynchronous telenetting alone would…
"Listen, Ian, while the telescope finishes slewing, could you set up to look at an amplitude-time plot? Let's call the low-amplitude pulses dots and the high-amplitude pulses dashes. We're getting… Yes that's just the pattern we've been seeing for the last half hour… Maybe. Well, it's the best candidate in five years, but I keep remembering how badly the Soviets got fooled with that Big Bird satellite incident around '74. Well, the way I understand it, it was a U.S. radar altimetry survey of the Soviet Union for cruise missile guidance… Yes, a terrain mapper. And the Soviets were picking it up on omnidirectional antennas. They couldn't tell where in the sky the signal was coming from. All they knew was they were getting the same sequence of pulses from the sky at about the same time every morning. Their people assured them it wasn't a military transmission, so naturally they thought it was extraterrestrial… No, we've excluded a satellite transmission already.
"Ian, could we trouble you to follow it for as long as it's in your sky? I'll talk to you about VLBI later. I'm going to see if I can't get other radio observatories, distributed pretty evenly in longitude, to follow it until it reappears back here… Yes, but I don't know if it's easy to make a direct phone call to China. I'm thinking of sending an IAU telegram… Fine. Many thanks,