Okay, enough maudlin claptrap already. Sheesh.
My best friend in high school and I used to challenge each other with (often semi-idiotic) thought questions - if dinosaurs were resurrected would they be kosher, and that sort of thing. There's one I've been mulling over for a few years now, and I think the time has come for it to see the light of day:
Take earth (please!), as it is now. Remove all people from it. Remove all representations of people from it - no statues, no video, no images. I don't care why everyone is gone, we just are. Maybe there was a disaster, or maybe we heard there were good investment opportunities in the Andromeda Galaxy. Anyway, we're all gone, leaving infrastructure, cars, office buildings, etc. intact. Now imagine that someone from an alien civilization lands on earth. Would he/she/it be able to determine what we looked like just from the things we made and used? Would they be able to tell we had a torso, a head up top, and four appendages? Five fingers on each of two hands? My guess is that in very gross terms (approximate height, size, shape), it would be possible to reconstruct us physically. How many (if any) of the physical details of our existence would be irreproducible, though?
I really don't know how I struck upon this question. I think it came to me as I was driving a few years ago.
Also: happy belated 50th birthday to the Lego brick. I think I still have my Junior Builder's Club card from ~1979 somewhere. I should laminate it and put it in my wallet.