See also, the Long Now Foundation: https://en.wikipedia.org/wiki/Long_Now_Foundation
...I think this might have been meant for another comment/thread anyway.
I think it's plausible that things we say or do now will matter 7900 years from now. The languages we speak today, and the beef, pork, and wheat we eat, are to a significant extent the result of the Bug-Dniester culture 7900 years ago; and Voyager 2 will very likely still exist 7900 years from now unless we catch up with it. And the advent of writing has made it much easier for direct cultural influence to span vast gaps of time.
I think it's very likely that the human species will become extinct within a century, but quite possible that something will survive because of what we say and do today.