Some history from an NGram graphic

Does this community know about Google NGram? It charts the frequency of occurrence of any word or phrase in published literature -- books, magazines, government reports, etc. -- anything that Google can vacuum up. I created this chart from it that shows that from 1950 to 1980 the alignment of "unidentified flying objects" with "weather modification" seems not to be coincidental. So should weather modification be part of the UAP story? Note especially that both terms faded from attention about...