2001_ A Space Odyssey - Arthur C. Clarke [42]
There was, as had long been known, a trace of atmosphere. When the dark edge of the satellite passed across a star, it dimmed briefly before the moment of eclipse. And in some areas there was a hint of cloud — perhaps a mist of ammonia droplets, borne on tenuous methane winds.
As swiftly as it had rushed out of the sky ahead, Europa dropped astern; and now Jupiter itself was only two hours away. Hal had checked and rechecked the ship’s orbit with infinite care, and there was no need for further speed corrections until the moment of closest approach. Yet, even knowing this, it was a strain on the nerves to watch that giant globe ballooning minute by minute. It was difficult to believe that Discovery was not plunging directly into it, and that the planet’s immense gravitational field was not dragging them down to destruction.
Now was the time to drop the atmospheric probes — which, it was hoped, would survive long enough to send back some information from below the Jovian cloud deck. Two stubby, bomb-shaped capsules, enclosed in ablative heat-shields, were gently nudged into orbits which for the first few thousand miles deviated scarcely at all from that of Discovery.
But they slowly drifted away; and now, at last, even the unaided eye could see what Hal had been asserting. The ship was in a near-grazing orbit, not a collision one; she would miss the atmosphere. True, the difference was only a few hundred miles — a mere nothing, when one was dealing with a planet ninety thousand miles in diameter — but that was enough.
Jupiter now filled the entire sky; it was so huge that neither mind nor eye could grasp it any longer, and both had abandoned the attempt. If it had not been for the extraordinary variety of color — the reds and pinks and yellows and salmons and even scarlets — of the atmosphere beneath them, Bowman could have believed that he was flying low over a cloudscape on Earth.
And now, for the first time in all their journeying, they were about to lose the Sun. Pale and shrunken though it was, it had been Discovery’s constant companion since her departure from Earth, five months ago. But now her orbit was diving into the shadow of Jupiter; she would soon pass over the night side of the planet.
A thousand miles ahead, the band of twilight was hurtling toward them; behind, the Sun was sinking swiftly into the Jovian clouds. Its rays spread out along the horizon like two flaming, down-turned horns, then contracted and died in a brief blaze of chromatic glory. The night had come.
And yet — the great world below was not wholly dark. It was awash with phosphorescence, which grew brighter minute by minute as their eyes grew accustomed to the scene. Dim rivers of light were flowing from horizon to horizon, like the luminous wakes of ships on some tropical sea. Here and there they gathered into pools of liquid fire, trembling with vast, submarine disturbances welling up from the hidden heart of Jupiter. It was a sight so awe-inspiring that Poole and Bowman could have stared for hours; was this, they wondered, merely the result of chemical and electrical forces down there in that seething caldron — or was it the by-product of some fantastic form of life? These were questions which scientists might still be debating when the newborn century drew to its close.
As they drove deeper and deeper into the Jovian night, the glow beneath them grew steadily brighter. Once Bowman had flown over northern Canada during the height of an auroral display; the snow-covered landscape had been as bleak and brilliant as this. And that arctic wilderness, he reminded himself, was more than a hundred degrees warmer than the regions over which they were hurtling now.
“Earth signal is fading rapidly,” announced Hal. “We are entering the first diffraction zone.”
They had expected this — indeed, it was one of the mission’s objectives, as the absorption of radio waves would give valuable information about the Jovian atmosphere.