I have read a handful of books that discuss various astronomical evidence (to crudely put it, various moon phases, eclipses, sighting of various stars and constellations in various parts of the sky etc as mentioned in these two epics). They place the Mahabharata happening and existence of some (historical) personality such as Krishna around 3100 BC and something of Ramayana kind around 5100/5000 BC. I believe the current government is turning vary sloppy in these matters and they forget they exist for the people and not the other way round!
