There were, to be sure, traces of other "civilizations" that were gone. A planet here and there had refined metal structures, not yet completely rusted away; others showed that somebody, sometime, had gone so far as to pollute its environment with certainly artificial radionuclides.
That was it.
And the more they found, the more the wonder grew. Where were the old civilizations? The ones who had reached Earth's stage of culture a million or a billion years before? Why hadn't they survived?
It was as though the first explorers into, say, the Amazon jungle had found huts, farms, villages, but instead of living denizens only corpses. The explorers would certainly wonder what had killed all the people off.
So wondered the Gateway prospectors. They could have accepted it if they had found no traces of any other intelligence (always, of course, not counting the Heechee themselves). Those members of the human race who cared about such things had been braced for that all along: the SETI searches and the cosmological
estimates had prepared them for a lonely universe. But there had been other creatures that appeared to have been capable of as much technology and as much wisdom as the human race. They had existed, and now they were gone.
What had happened?
It was a long time before the human race found out the answer to that, and then they didn't like it at all.
While human beings were beginning to thread their way across the immensity of the galaxy, the world they had left behind was beginning to change. It took a long time, but at last the Heechee wonders the Gateway prospectors had brought home were beginning to make a real change for the better in the condition of the peoples of the Earth-even the poorest ones.
One key discovery unlocked all the rest. That was learning how to read the Heechee language. The hardest part of that was finding any Heechee language to read, because the Heechee did not seem to have been familiar with things like pencils, paper, or printing. It was a sure-thing bet in the opinion of everybody who ever gave it a thought that the Heechee must have had some way of recording things, but where was it?
When the answer turned up it was obvious enough: the longmysterious "prayer fans" were actually Heechee "books." That is, it was obvious after the fact-though the tricky bit was that the things couldn't be read without some high-tech aid.
Once the records were identified as records, the rest was up to
linguists. It wasn't all that hard. It certainly was no harder, say, than the long-ago decipherment of "Linear B," and it was made easier by the fact that places were discovered, on "Heechee Heaven" and elsewhere, where parallel texts could be found in both languages.
When the prayer fans were interpreted, some of the most intractable Heechee mysteries became crystal clear. Not the least of them was how to reproduce the Heechee faster-than-light drive. Then colonization could really begin. The great ship that had been called "Heechee Heaven" was the first to be used for that purpose, because it was already there. It ferried thousands of poverty-stricken emigrants at a time to new homes on places like Peggy's Planet, and that was only the beginning. Within five years that ship was joined by others, now human made-just as fast; even bigger.
And on the home planet itself...
On the home planet itself, it was the CHON-food factories that made the first big difference.
Simply put, what they did was end human starvation forever. The Heechee's own CHON-food factories orbited in cometary space-that was the reason for the long-baffling Heechee fascination with Oort clouds, now answered at last. The human-made copies of
these factories could be sited anywhere-that is, anywhere there was a supply of the basic four elements. The only other raw material they needed was enough of a salting of impurities to fill out the dietary needs.
So before long the CHON-food factories sat on the shores of the Great Lakes in North America and Lake Victoria in Africa and everywhere else where water and the four elements were present and people wanted to eat. They were along the beaches of every sea. No one starved anymore.
No one died of hunger before his time-and before long it was almost true that no one died at all. This was for two reasons. The first of them had to do with surgery, and, peculiarly, with the CHON-food factories, as well.
For a long time human beings had known how to substitute transplants for any worn-out organ. Now the replacement parts no longer had to be butchered out of cadavers. The same system that made CHON-food, considerably refined, could be induced to manufacture tailor-made human organs to implant into people in need. (A whole wicked industry of assassinations for the marketplace collapsed overnight.) Nobody had to die because a heart, lung, kidney,
