We have one piece of evidence (of the geological condition of the Sphinx) that links the remains of ancient civilizations to dates that precede conventional assumptions to such a degree that any more pieces of information found along these lines will prove to be the death sentence for mainstream Egyptology and Archaeology... as any science that no longer uses the other sciences, to verify it's work in whatever context it can be utilized for, is no longer a science but a cult.
In the following documentary, Robert Bauval talks about the astronomical alignments he uncovered in the pyramid complex at Giza that suggest that this site has been in use in some form or another since 10,500 BC. We already know Megalithic Cultures go back to at least 9500 BC (or longer if we take into account ocean rise) and we know many Megalithic cultures were obsessed with observing the sky, documenting it in stone and developing the site with more structures over time. (This is breaking news as far as the fields of Egyptology and Archaeology is concerned.)
Documentary: Egypt Exposed: The True Origin Of Civilizations with Robert Bauval
Summarizing some of the theories presented here:
2 major takeaways from this documentary for this blog post series
Other interesting discoveries concern the dating of two of the Indian classics using astronomical data to, what is basically, the stone age, i.e. 5561 BC for the Mahabharata war and the date of 7600 BC for the story of the Ramayana.
It may be that the stories accumulated astronomical data over the years randomly and they coincidentally coincide with those dates in history. It is also possible, given how mythology tends to remain constant over large epochs of time, that these astronomical details have always been a part of the story. We do have evidence of primitive tribes tracking the sky, for what appears to be, thousands of years AND the Megalithic Cultures seem to have emerged with advanced astronomical observations encoded in some of their structures.