The astronomer Paul Davies has pointed to what might be literally the greatest conundrum in the universe. There is more reason than ever to believe that no matter how steep the odds, with the force of immense numbers of earth-like planets circling sun-like stars for billions of years, many of these planets are home to complex intelligence. And even though human space exploration has been in the doldrums, our tools for exploring space are breathtaking. Even in the Sputnik age, when they were far more modest, a generation grew up hoping or fearing contact. ("I want to meet an alien," one of them declared at a science fiction meeting where I spoke ten years ago, finding cyberspace a pale substitute for the real thing.) Over 75 percent of responding Journal readers believe in extraterrestrial intelligence.
I'm skeptical not so much about the existence of aliens -- I don't think any probabilistic speculation is meaningful -- as about the likelihood of detecting signals from them, let alone communicating. I also recognize that I could suddenly be proved totally wrong, especially by some new class of instrument. In fact, I'd love to be. So I say go SETI!
But if we want to get to know weird alternative forms of intelligence, we don't have to search the skies. They're swimming around us. Deep human diving has been neglected even more than human space exploration. The deep submersible record was set 50 years ago by Don Walsh and Jacques Picard. When the Navy recognized Walsh as a "national treasure" a week ago, The Washington Post reported:
On the surface, [Piccard and Walsh] had time to reflect. "How soon before somebody comes back?" Walsh said they wondered. "A year? Two years?"
He and Jacques Piccard were in the national spotlight for a time. Walsh wrote his version of the story for Life magazine; Piccard wrote his for National Geographic. Both men were invited to the White House to meet President Dwight D. Eisenhower.
But their moment faded, and the world's gaze was soon fixed on the heavens.
In 1961, Jacques Piccard predicted in his book that "within a few years the rush into outer space will be matched by an . . . invasion of inner space."
And over the years, other vessels have indeed visited Challenger Deep, but never with humans on board.
This week, a half-century after Trieste's famous descent, Walsh said they had been certain man would soon return.
"Never happened," he said.
Deep-sea vent exploration has continued, with constant discoveries of new exotic life forms -- which of course may have counterparts on other planets. But they have the advantage of being right here. As the Columbia University geophysicist Maya Tolstoy told The New York Times:
''We know more about the surface of the Moon and Mars than we do about our own planet because two-thirds of our planet is covered by ocean making it very hard to explore,'' she said.
''We've only seen a tiny fraction of the deep sea floor so there are undoubtedly many more vents and other amazing things to discover.''
My favorite alien is the octopus. Not that I'll try to compare its intelligence with our own, but it represents a radically different and superbly adapted body plan and brain, just what we might expect from a space visitor.
The classics of underwater alien-hunting remain the wonderfully weird films of Jean Painlevé, now available as a DVD. Who knows what new generations of submersibles, manned and unmanned, might find?