After a lifetime in this subject, I have concluded that the extraterrestrial hypothesis is one reasonable tentative approach to putting the best-documented and most puzzling UFO reports into a scientifically defensible conceptual framework. By such reports I mean those with… — Jerome Clark Copy Share Image
We can make a similar examination, but with greater uncertainty, of the extraterrestrial hypothesis that holds that a wide range of UFOs viewed on the planet Earth are space vehicles from planets of other stars. — Carl Sagan Copy Share Image
