So far history of the world, particularly of Indian subcontinent, is based on linguistic guesswork and religious beliefs/hearsay.
However, during last 30-40 years, several new scientific tools and techniques have been developed, which are capable to determining the dates of any ancient events in scientific and precise manner.
Also, most people believe that Buddha existed and that he actually lived.
Thousands of years later, when some of these Himalayan Rivers became non-perennial or started drying up, some of these people started moving towards Central Asia and Europe.
There could well be artificial structures that cannot be seen in the images.
1b) The continuity of the linear feature seen in the satellite images is an illusion caused by suspension of calcium carbonate sediment and cloud cover.
Consequently the civilizations of the world naturally and simultaneously started developing near the rivers which initially started flowing due to the melting of glaciers near the Equator e.g. When populations multiplied, these river waters became insufficient.
Therefore some people started travelling from south to north.