Carl sagan — contact. chapter 3 — white noise
The pulses had been journeying for years through the great dark between the stars. Occasionally, they would intercept an irregular cloud of gas and dust, and a little of the energy would be absorbed or scattered. The remainder continued in the original direction. Ahead of them was a faint yellow glow, slowly increasing in brightness among the other unvarying lights. Now, although to human eyes it would still be a point, it was by far the brightest object in the black sky.
The pulses were encountering a horde of giant snowballs.
Entering the Argus administration building was a willowy woman in her late thirties. Her eyes, large and set far apart, served to soften the angular bone structure of her face. Her long dark hair was loosely gathered by a tortoise barrette at the nape of her neck. Casually dressed in a knit T-shirt and khaki skirt, she strolled along a hallway on the first floor and entered a door marked “E. Arroway, Director.” As she removed her thumb from the fingerprint deadlock, and observer might have noticed a ring on her right hand with an oddly milky red stone unprofessionally set in it. Turning on a desk lamp, she rummaged through a drawer, finally producing a pair of earphones. Briefly illuminated on the wall beside her desk was a quotation from the Parables of Franz Kafka:
“Now the Sirens have a still more fatal weapon than their song, namely their silence…
Someone might possibly have escaped from their singing;
but from their silence, certainly never.”
Extinguishing the light with a wave of her hand, she made for the door in the semidarkness.
In the control room she quickly reassured herself that all was in order. Through the window she could see a few of the 131 radio telescopes that stretched for tens of kilometers across the New Mexico scrub desert like some strange species of mechanical flower straining toward the sky. It was early afternoon and she had been up late the night before. Radio astronomy can be performed during daylight, because the air does not scatter radio waves from the Sun as it does ordinary visible light. To a radio telescope pointing anywhere but very close to the Sun, the sky is pitch black. Except for the radio sources.
Beyond the Earth's atmosphere, on the other side of the sky, is a universe teeming with radio emission. By studying radio waves you can learn about planets and stars and galaxies, about the composition of great clouds of organic molecules that drift between the stars, about the origin and evolution and fate of the universe. But all these radio emissions are natural — caused by physical processes, electrons spiraling in the galactic magnetic field, or interstellar molecules colliding with one another, or the remote echoes of the Big Bang red-shifted from gamma rays at the origin of the universe to the tame and chill radio waves that fill all of space in our epoch.
In the scant few decades in which humans have pursued radio astronomy, there has never been a real signal from the depths of space, something manufactured, something artificial, something contrived by an alien mind. There have been false alarms. The regular time variation of the radio emission from quasars and, especially, pulsars had at first been thought, tentatively, tremulously, to be a kind of announcement signal from someone else, or perhaps a radio navigation beacon for exotic ship that plied the spaces between the stars. But they had turned out to be something else — equally exotic, perhaps, as a signal from beings in the night sky.