Science History

 Fascinating talk by science historian Owen Gingerich about how Copernicus' heliocentrism book was received and understood based on his reading of the notations in 600 first and second editions of the book that he found on an international detective story.  This includes the censored version the Church allowed to circulate after adding it to the Index of Forbidden Books.  They did not reprint it.  They applied green ink to the "naughty" passages.