Why was Carl Sagan denied tenure at Harvard?

It was well-known in the science community back in the day that Carl Sagan was more than just a scientist or an academic researcher.

In the scientific community, it was perceived and is still prevalent to this day that a researcher must have one narrow topic that they can shed more light on the subject with their research. However, Carl Sagan was a scientist with multiple interests and was denied tenure by Harvard University in 1967.

It was alleged that an adviser from his early years during his undergraduate years even wrote to Harvard to deny tenure to the scientist.

Due to his role as a science communicator, he earned some raff from the established scientific society at the time.

Thirteen years later in 1980, Sagan co-wrote a scientific TV show that made science fun and accessible to millions who would watch television at the end of the day to pass some leisurely time with the family.

The 13-part television series by show narrated by Sagan, “Cosmos: A Personal Voyage”, became the highest  watched series in the history of American television till 1990.

At least half a billion people worldwide, in at least 60 countries, have watched the award-winning TV show that presented bite-sized science facts and trivias and helped inspire a generation of scientists and astronomers.

Following the success of the series, Sagan wrote a book by the same name to go along with it.