I was thinking about this some more last night. In a way, the past is really here with use. Every atom that made everything historical is here with us today on this Earth (With a few exceptions, like atoms blasted away by impactors, atoms that escape into in the upper atmosphere, and atoms us humans have sent off this Earth. And there are the atoms that have fallen to earth in meteors and space dust)

The very atoms that make you up have travel with the Earth since the Earth formed. A few may have come here from space since that time. It would be interesting if we new where our atoms have been since they were made in the heart of some long dead star (With the exception of those atoms that were formed from the Big Bang).