http://www.youtube.com/watch?v=bQNhQ7wxOvA
When colonial British got hold of these ancient texts (surya (sun) siddhanta (principles), their scientists concluded the text were written around 580bce.
Do watch this video on how he disagrees and deduces a time around 12000bce when the pole star was not Polaris but vegas in the north pole. Something many other non Hindu civilizations alluded to in their scriptures.
Graham Hancock has another proof for his books
Yes, the pyramids are much much older.
Wake up folks!!