Extracted from “Where are They?” copyright Arthur C. Clarke (1986):
“Nowadays, anyone who considers that alien supercivilisations may exist has to contend not with skepticism but with something much worse – credulity. Although the subject now effects me with uncontrollable fits of yawning, I would be failing in my duty if I did not say something on UFOs.
“So here, as briefly as possible, are the conclusions I’ve come to after more than fifty years of study:
“1. There may be strange and surprising meteorological, electrical, or astronomical phenomena still unknown to science, which may account for the very few UFOs that are both genuine and unexplained.
“2. There is no hard evidence that Earth has ever been visited from space.
“3. If that does happen, there are at least three independent global radar networks that will know within a matter of minutes. And in the unlikely event that the US, [Russian] and Chinese authorities instantly cooperate to suppress the news, they’ll succeed for a maximum of forty-eight hours. How long do you imagine such a secret could be kept? Remember how quickly Watergate unravelled.
“Having written thousands of words on the subject (and read millions) I refuse to go into further details. If anyone wants to argue, I’ll merely quote one of my favourite book titles: ‘Shut up, he explained.'”