On Halloween more than 40 years ago, Orson Welles broadcast a program that purported to tell about our being invaded by troops from Mars. I listened for a few minutes, found the drama too far-fetched, and turned to another program.

Later there was a big hullabaloo because millions of people thought the invasion reports were true.

A few days ago, an obscure FM station in this area put on a program during which an excited announcer broke in with the urgent message that the United States was under nuclear attack. "This is not a test," he said. "The United States is under attack!" Many who were tuned to the station thought -- quite understandably -- that their lives were in imminent danger.

I find myself wondering why I had been so sure the Welles broadcast was a hoax whereas the nuclear attack broadcast of last week would have frightened me out of my wits. The only answer that suggests itself is that in 1938 we could be reasonably sure Martians were not trying to conquer the earth, whereas in 1980 the possibility of a nuclear attack against the United States is very real.

A station that broadcasts material of this kind raises the question of whether it is being operated in the public interest. I doubt it.