"Make a rough estimate."
Ball looked at the captain, knowing what was in his mind. He smiled
wryly and said: "Five thousand years? Ten thousand? I don't know."
Steffens whistled.
Ball pointed again at the wall. "Look at the striations. You can tell
from that alone. It would take even a brisk Earth wind _at least_
several thousand years to cut that deep, and the wind here has only a
fraction of that force."
The two men stood for a long moment in silence. Man had been in
interstellar space for three hundred years and this was the first
uncovered evidence of an advanced, space-crossing, alien race. It was
an historic moment, but neither of them was thinking about history.
Man had been in space for only three hundred years. Whatever had built
these had been in space for thousands of years.
Which ought to give _them_, thought Steffens uncomfortably, one hell of
a good head-start.
* * * * *
While the excav crew worked steadily, turning up nothing, Steffens
remained alone among the buildings. Ball came out to him, looked dryly
at the walls.
"Well," he said, "whoever they were, we haven't heard from them since."
"No? How can you be sure?" Steffens grunted. "A space-borne race was
roaming this part of the Galaxy while men were still pitching spears
at each other, _that_ long ago. And this planet is only a parsec from
Varius II, a civilization as old as Earth's. Did whoever built these
get to Varius? Or did they get to Earth? How can you know?"
He kicked at the sand distractedly. "And most important, where are they
now? A race with several thousand years...."
"Fifteen thousand," Ball said. When Steffens looked up, he added:
"That's what the geology boys say. Fifteen thousand, at the least."
Steffens turned to stare unhappily at the buildings. When he realized
now how really old they were, a sudden thought struck him.
"But why buildings? Why did they have to build in stone, to last?
There's something wrong with that. They shouldn't have had a need
to build, unless they were castaways. And castaways would have left
_something_ behind. The only reason they would need a camp would be--"
"If the ship left and some of them stayed."
Steffens nodded. "But then the ship must have come back. Where did it
go?" He ceased kicking at the sand and looked up into the blue-black
midday sky. "We'll never know."
"How about the other planets?" Ball asked.
"The report was negative. Inner too hot, outer too heavy and cold. The
third planet is the only one with a decent temperature range, but _it_
has a CO_{2} atmosphere."
"How about moons?"