RE: Carl Sagan's video
The reason Sagan touts the blind luck of ancient Indian mystics in guessing certain facts about the universe is to demonstrate to the people in the West that their chosen superstitions are silly. Of course many of the tales that festivals such as Pongal are based on are just superstitions.
The one thing that we must keep in mind is that some superstitions become 'naturalized' over time because the core values that they express is vital to human celebration of life and nature. I think that Pongal is one of these festivals that may be possibly naturalized at some point in the future. But for this to happen a lot must change, and the easier answer may be to simply create a new naturalized celebration of the harvest festival. In the West, harvest festivals are considered pagan rites, and strangely enough, many of those who are pagans today are not believers in the supernatural. They just personify nature and use the myths as feel-good stories for sake of ritual. They really are pantheists. I don't like going that far, but if we want to "save" certain cultural celebrations that are distinctly Indian in flavor, we must strive to create naturalized social celebrations of our cultural heritage. In India we have the problem that the majority still looks at these celebrations of nature through superstitious eyes, which is why I think that in some cases creating entirely new festivals may be the answer.
"Fossil rabbits in the Precambrian"
~ J.B.S.Haldane, on being asked to falsify evolution.