Contact - Carl Sagan [157]
"Do we have time for some questions before…whatever it is we have to do next?"
"Sure. One or two anyway." `Tell me about your transportation system."
"I can do better than that," he said. "I can show you. Steady now."
An amoeba of blackness leaked out from the zenith, obscuring Sun and blue sky. "That's quite a trick," she gasped. The same sandy beach was beneath her feet. She dug her toes in. Overhead…was the Cosmos. They were, it seemed, high above the Milky Way Galaxy, looking down on its spiral structure and falling toward it at some impossible speed. He explained matter-of-factly, using her own familiar scientific language to describe the vast pinwheel-shaped structure. He showed her the Orion Spiral Arm, JH which the Sun was, in this epoch, embedded. Interior to it, in decreasing order of mythological significance, were the Sagittarius Arm, the Norma/Scutum Arm, and the Three Kiloparsec Arm.
A network of straight lines appeared, representing the transportation system they had used. It was like the illuminated maps in the Paris Metro. Eda had been right. Each station, she deduced, was in a star system with a low-mass double black hole. She knew the black holes couldn't have resulted from stellar collapse, from the normal evolution of massive star systems, because they were too small. Maybe they were primordial, left over from the Big Bang, captured by some unimaginable starship and towed to their designated station. Or maybe they were made from scratch. She wanted to ask about this, but the tour was pressing breathlessly onward.
There was a disk of glowing hydrogen rotating about the center of the Galaxy, and within it a ring of molecular clouds rushing outward toward the periphery of the Milky Way. He showed her the ordered motions in the giant molecular cloud complex Sagittarius B2, which had for decades been a favorite hunting ground for complex organic molecules by her radio-astronomical colleagues on Earth. Closer to the center, they encountered another giant molecular cloud, and then Sagittarius A West, an intense radio source that Ellie herself had observed at Argus.
And just adjacent, at the very center of the Galaxy, locked in a passionate gravitational embrace, was a pair of immense black holes. The mass of one of them was five million suns. Rivers of gas the size of solar systems were pouring down its maw. Two colossal-she ruminated on the limitations of the languages of Earth-two super massive black holes are orbiting one another at the center of the Galaxy. One had been known, or at least strongly suspected. But two? Shouldn't that have shown up as a Doppler displacement of spectral lines? She imagined a sign under one of them reading ENTRANCE and under the other EXIT. At the moment, the entrance was in use; the exit was merely there.
And that was where this Station, Grand Central Station, was-just safely outside the black holes at the center of the Galaxy. The skies were made brilliant by millions of nearby young stars; but the stars, the gas, and the dust were being eaten up by the entrance black hole. "It goes somewhere, right?" she asked. "Of course."
"Can yon tell me where?"
"Sure. All this stuff winds up in Cygnus A." Cygnus A was something she knew about. Except only for a nearby supernova remnant in Cassiopeia, it was the brightest radio source in the sides of Earth. She had calculated that in one second Cygnus A produces more energy than the Sun does in 40,000 years. The radio source was 600 million light-years away, far beyond the Milky Way, out in the realm of the galaxies. As with many extragalactic radio sources, two enormous jets of