It came in vertically, punching a hole 10 km wide through the atmosphere, generating temperatures so high that the air itself started to burn. When it hit the ground near the Gulf of Mexico, rock turned to liquid and spread outward in mountainous waves, not freezing until it had formed a crater 200 km across.
That was only the beginning of disaster: now the real tragedy began. Nitric oxides rained from the air, turning the sea to acid. Clouds of soot from incinerated forests darkened the sky, hiding the sun for months. Worldwide, the temperature dropped precipitously, killing off most of the plants and animals that had survived the initial cataclysm. Though some species would linger on for millenniums, the reign of the great reptiles was finally over.
The clock of evolution had been reset; the countdown to Man had begun. The date was, very approximately, 65 million B.C.
CAPTAIN ROBERT SINGH never tired of walking in the forest with his little son Toby. It was, of course, a tamed and gentle forest, guaranteed to be free of dangerous animals, but it made an exciting contrast to the rolling sand dunes of their last environment in the Saudi desert -- and the one before that, on Australia's Great Barrier Reef. But when the Skylift Service had moved the house this time, something had gone wrong with the food-recycling system. Though the electronic menus had fail-safe backups, there had been a curious metallic taste to some of the items coming out of the synthesizer recently.
"What's that, Daddy?" asked the four-year-old, pointing to a small hairy face peering at them through a screen of leaves.
"Er, some kind of monkey. We'll ask the Brain when we get home."
"Can I play with it?"
"I don't think that's a good idea. It could bite. And it probably has fleas. Your robotoys are much nicer."
"But . . ."
Captain Singh knew what would happen next: he had run this sequence a dozen times. Toby would begin to cry, the monkey would disappear, he would comfort the child as he carried him back to the house . . .
But that had been 20 years ago and a quarter-billion kilometers away. The playback came to an end; sound, vision, the scent of unknown flowers and the gentle touch of the wind slowly faded. Suddenly, he was back in this cabin aboard the orbital tug Goliath, commanding the 100-person team of Operation ATLAS the most critical mission in the history of space exploration. Toby, and the stepmothers and stepfathers of his extended family, remained behind on a distant world which Singh could never revisit. Decades in space -- and neglect of the mandatory zero-G exercises -- had so weakened him that he could now walk only on the Moon and Mars. Gravity had exiled him from the planet of his birth.
"One hour to rendezvous, captain," said the quiet but insistent voice of David, as Goliath's central computer had been inevitably named. "Active mode, as requested. Time to come back to the real world."