Chapter 19 Passing Jupiter

Even from thirty million kilometres away, Jupiter was already the biggest object in the sky ahead. The planet was now a pale pink circle, about half the size of the Moon when seen from the Earth. Moving around its middle were the bright stars of Io, Europa, Ganymede and Callista. Each one of them was as big as a planet, but here they were just satellites of an enormous master.

In fact, Bowman had not really understood how big Jupiter was until, one day in the electronic library, he saw a picture. It showed the surface of Earth taken off, then fixed like the skin of an animal on the shape of Jupiter. Against this background, all the continents and oceans of Earth appeared smaller than India on a map of the world.

When Bowman used the ship's telescope, he saw only racing clouds that had been pulled out into long bands by the planet's fast turning speed. Hidden beneath those clouds was more material than in all of the other planets of the Solar System. And what else, Bowman wondered, was also hidden there? Over the radio connection with Earth, the information was going back in a constant stream. They were now so far from home that, even travelling at the speed of light, their signals were taking fifty minutes for their journey. Though the whole world was looking over their shoulders, watching through their eyes and their instruments as Jupiter approached, it would be almost an hour before the news of their discoveries reached home.

Discovery passed within thirty thousand kilometres of Europa, and all instruments were aimed at the approaching world. Here were twenty-two million square kilometres of land which, until this moment, had never been more than a tiny spot in the best telescope. From a distance it had seemed like an enormous snowball, and closer observation showed that it really was a brilliant white. Unlike the dusty Moon, its surface was covered with shining objects that looked like large pieces of ice. Almost certainly these were formed mainly from water that Jupiter's gravity had somehow failed to capture.

As quickly as it had rushed out of the sky ahead, Europa dropped behind the ship, and now Jupiter itself was only two hours away. Even though Hal constantly checked and rechecked the ship's orbit, it was difficult to believe they were not flying straight into the enormous planet.

Now was the time to drop the atmospheric probes which, it was hoped, would continue to operate long enough to send back some information from below the clouds. As they slowly fell away, it was possible to see that the ship was in a steady orbit and would circle the planet safely.

And now, for the first time, they were going to lose the Sun. Though it was much smaller now, it had been with them for the whole of their five-month journey. As their orbit dived into the shadow of Jupiter, they watchedit sink into the great clouds. There was a moment of flashinglire all along the horizon, then night came.

But the great world below was not wholly dark. Faint rivers of light moved from horizon to horizon. Here and there they gathered into pools of liquid fire, always moving, constantly changed by what was happening below. It was a wonderful sight, and it held Poole and Bowman's attention.

' Earth signal is dying rapidly' announced Hal.' We are entering the first silent area.'

They had been expecting this, but they felt a great loneliness. The radio silence would only last for an hour, but that hour would be the longest of their lives.

Jupiter was now an enormous wall of fire, stretching out of sight above them — and the ship was climbing straight up the side of it. Though they knew they were moving far too quickly for even Jupiter's gravity to capture them, it was hard to believe that Discovery had not become a satellite of this enormous world.

At last, far ahead, there was light along the horizon. They were leaving the shadow, heading out towards the Sun. And then Hal announced,' I am in radio contact with Earth. I am also happy to say that the orbit has been successful. Our time to Saturn is one hundred and sixty-seven days, five hours, eleven minutes.'

That was within a minute of the original calculation. Discovery had successfully used the enormous gravity of Jupiter to increase her own speed by several thousand kilometres an hour. She had drawn energy from the great planet itself, which was now carrying it deeper into space.

But the laws of nature remained unbroken. As the speed of the ship had increased, Jupiter had slowed down, but by such a small amount that it could never be measured. The time had not yet come when Man could leave his mark on the Solar System.

As the light grew quickly around them, and the small Sun lifted again into Jupiter's sky, Poole and Bowman reached out silently and shook each other's hands.

Though they could hardly believe it, the first part of the mission was safely over.