Contact - Carl Sagan [33]
She knew it was only a few days after receipt of the message, but she was at once exhilarated and deeply disappointed. After all these years, they had finally received a signal-sort of. But its content was shallow, hollow, empty. She had imagined receiving the Encyclopedia Galactica.
We've only achieved the capacity for radio astronomy in the last few decades, she reminded herself, in a Galaxy where the average star is billions of years old. The chance of receiving a signal from a civilization exactly as advanced as we are should be minuscule. If they were even a little behind us, they would lack the technological capability to communicate with us at all. So the most likely signal would come from a civilization much more advanced. Maybe they would be able to write full and melodic mirror fugues: The counterpoint would be the theme written backwards. No, she decided. While this was a kind of genius without a doubt, and certainly beyond her ability, it was a tiny extrapolation from what human beings could do. Bach and Mozart had made at least respectable stabs at it.
She tried to make a bigger leap, into the mind of someone who was enormously, orders of magnitude, more intelligent than she was, smarter than Drumlin, say, or Eda the young Nigerian physicist who had just won the Nobel Prize. But it was impossible. She could muse about demonstrating Fermat's Last Theorem or the Goldbach Conjecture in only a few lines of equations. She could imagine problems enormously beyond us that would be old hat to them. But she couldn't get into their minds; she couldn't imagine what thinking would be like if you were much more capable than a human being. Of course. Nor surprise. What did she expect? It was like trying to visualize a new primary color or a world in which you could recognize several hundred acquaintances individually only by their smells… She could talk about this, but she couldn't experience it. By definition, it has to be mighty hard to understand the behavior of a being much smarter than you are. Buy even so, even so: Why only prime numbers?
* * *
The Argus radio astronomers had made progress in the last few days. Vega had a known motion-a known component of its velocity toward or away from the Earth, and a known component laterally, across the sky, against the background of more distant stars. The Argus telescopes, working together with radio observatories in West Virginia and Australia, had determined that the source was moving with Vega. Not only was the signal coming, as carefully as they could measure, from where Vega was in the sky; but the signal also shared the peculiar and characteristic motions of Vega. Unless this was a hoax of heroic proportions, the source of the prime number pulses was indeed in the Vega system. There was no additional Doppler effect due to the motion of the transmitter, perhaps tied to a planet, about Vega. The extraterrestrials had compensated for the orbital motion. Perhaps it was a kind of interstellar courtesy.
"It's the goddamnedest most wonderful thing I ever heard of. And it's got nothing to do with our shop," said an official of the Defense Advanced Research Projects Agency, preparing to return to Washington.
As soon as the discovery had been made, Ellie had assigned a handful of the telescopes to examine Vega in a range of other frequencies. Sure enough, they had found the same signal, the same monotonous succession of prime numbers, beeping away in the 1420 megahertz hydrogen