[AntiGuv]

Because our space age civilization has fashioned innumerable items that we know should retain their basic form (sufficiently enough to establish their origin) longer than 2-3 billion years. Moreover, I can deduce this from reviewing what has in fact survived from 2-3 billion years ago, and comparing the resilience of that to the resilience of items that would evidence our civilization is not a difficult exercise.

PS. Unless a meteor strikes it, the flag on the moon will be enough.

[Nowhere Man]

Because our space age civilization has fashioned innumerable items that we know should retain their basic form (sufficiently enough to establish their origin) longer than 2-3 billion years. Moreover, I can deduce this from reviewing what has in fact survived from 2-3 billion years ago, and comparing the resilience of that to the resilience of items that would evidence our civilization is not a difficult exercise.

I've always wondered about things like that myself, like if we got nuked, how long will the buildings in the cities last (assuming they survived the nukes or were not targeted), the Interstate Highway system, and so forth. I'm currently in a "play by e-mail" Morrow Project role playing game and I remember the referee giving descriptions like "you're driving the V-150 (armored car) down the crumbling remains of I-64."

The Morrow Project is a post nuclear war/apocalyptic role playing game where the characters are frozen in order to wake up 3 to 5 years after the nuke war (or any other civilization busting catastrophe) in order to rebuild the United States. Things have gone wrong and you wake up to a changed world 150 +/- years later.