COSMIC BACKGROUND HISTORY. This is the overall history of the
KNOWN GALAXY. Not just since
EARTH HUMANS started running around there (see
FUTURE HISTORY), but from when intelligent life first appeared.
Cosmic Background History is usually touched over very lightly. No, actually it tends to be ignored altogether. This is for a good reason: it is basically impossible to write, or even to imagine in any convincing way. Making up a few hundred or thousand years of history is one thing; making up ten billion years of it is quite another.
Even if you assume that the earliest intelligent races took nearly as long to evolve as we did - say, arriving on the scene only 5 percent sooner, in cosmic terms just barely ahead of us - that gives you a piddly 500 million years of their history to make up. At one paragraph per million years, a Brief Historical Sketch would run a hundred pages or so. And then there's the awkward question of
TECHLEVEL. Did the first arrivers close their patent office for that whole 500 million years? If not, they must be a tad ahead of us.
This is probably why
ALIENS have gone rather out of fashion in
SPACE SF. (Though not in
HOLLYWOOD SCIFI, whose audience is presumed not to worry about these things.) Get rid of Aliens and you don't have to worry about people 500 million years ahead of us. But even that doesn't get rid of all the problems. If the Known Galaxy is full of
HABITABLE PLANETS - and it usually is - life, even complex life, must be pretty common. Why then no other spacefaring civilizations? (And, if there's
FTL, which there also usually is, they can get around pretty easily; 500 million years is plenty of time to hop a few galaxies over.)
There is no good solution to all of this. Which is why most SF writers just brush Cosmic Background History aside and ignore the whole issue. You should do so, too. Go on to the next item, and forget you ever read this one. Thinking about it too much will only make your head spin.
