I've often thought if there has been previous advanced civilizations on earth
If it was long enough ago we could easily not have found real evidence. I’m talking millions of years ago. If they reached a level of advancement to reach the moon it would be the ideal place to leave a historic record. Would not have to worry about erosion like on earth, records could survive millions of years until someone else with a similar level of advancement came along.
Kick in to the DU tip jar?
This week we're running a special pop-up mini fund drive. From Monday through Friday we're going ad-free for all registered members, and we're asking you to kick in to the DU tip jar to support the site and keep us financially healthy.
As a bonus, making a contribution will allow you to leave kudos for another DU member, and at the end of the week we'll recognize the DUers who you think make this community great.