The Air Force says no flying saucers landed in New Mexico 50 years ago, but don't tell that to the woman I love.
"I hope you're not going to write that there are no such things as alien spacecraft," she said the other day. "Because remember: I saw one."
It happened, she told me, during her student days at the University of Maryland College Park. One evening she and a group of friends were having a pizza party in the dorm. Suddenly there was a buzzing sound, and they all ran to the window. Outside, she said, a huge object appeared motionless in the sky, its sides lined with flashing lights of different colors.
The craft seemed to hang suspended for a moment. Then it zipped away at what seemed like incredible speed and vanished from view.
To me, there has always been a simple explanation for the strange happening that night: The pepperoni on the pizza was not quite fresh.
But I realize there are many people who will remain convinced that we are being visited by space aliens no matter what the government says.
Certainly, evidence of intelligent civilizations on planets orbiting distant stars would be an epochal event in human history. The scientific, political and religious implications would be profound.
Yet there's also a dark side to our fascination with life elsewhere in the cosmos, though it has nothing to do with little green men or UFOs.
It is simply that so magnificent a concept forces us to confront the tenuousness of our own hold on the universe as an intelligent species and the fragility of our civilization.
It is relatively easy, for example, to estimate the likelihood of intelligent species elsewhere in our galaxy. One first needs to consider the number of stars similar to our sun, then the proportion of those stars that have planetary systems, then the number of those systems likely to have planets similar to Earth, etc.
Based on such considerations, it appears likely that there are many millions of other places where the physical conditions for life are just as suitable as they are on Earth. The British astronomer Fred Hoyle and others have suggested that intelligent life could have evolved on as many as 1 million planets since the universe began some 15 billion years ago.
The probability of 1 million planets inhabited by intelligent creatures might at first seem cause for optimism. But then one has to consider the likelihood of any two intelligent civilizations existing at the same time, making communication possible between them.
It turns out that such communication is likely only among technologically advanced civilizations with an average life span of about 15,000 years. Industrial civilization on Earth, by contrast, is barely a century old.
In other words, even if there is intelligent life elsewhere in the universe, many more thousands of years may pass before we are likely to discover it.
This might be fine if we could be assured of a dozen or so more millenniums of uninterrupted development. Unfortunately, we may not have such a grace period.
Considering the huge growth in human populations, the accelerating pressure on natural resources, the menace of nuclear proliferation, we may well wonder whether our technical civilization can survive beyond a few more decades. Devastating crises may shortly overtake us, leading inevitably to a lapse into barbarism.
By the time the little green men finally arrive, we may well have reverted to a Stone Age existence, if we have not exterminated ourselves entirely.
Is this is too pessimistic a view? No more so than the popular image of menacing aliens in sci-fi fantasies like last summer's "Independence Day." The fearsome invaders in that film, after all, inflicted no evil on humanity that humanity had not already tried to inflict upon itself. Their unreasoning hostility and violence is merely a psychological projection of our own self-destructive impulses.
I would like to believe the human species will find a way to overcome the stupendous problems that threaten it today, and that intelligent life on Earth may survive to realize its astounding potential. If we fail, however, the fault will not have been in our stars, as the poet said, but in ourselves.