The thing to keep in mind is that we're still in the very early days when it comes to the search for extraterrestrial intelligence. Saying there's a silence is a bit like if Columbus, looking to discover a new continent, only sailed 10 miles off the coast of Spain before turning back to say, 'Nothing out there!'

Our computers double in capability on time scales of only a few years. It's hardly outrageous to believe that we will successfully develop thinking machines within a handful of decades, or at most a century or two. If that happens, these artificial sentients will quickly leave us behind.

The majority of my UFO diet consists of reports describing suspected encounters. This is not surprising, as there are thousands of sightings annually. The emailer has seen something unusual in the sky that he interprets as probable evidence of alien presence.

By 2020, most home computers will have the computing power of a human brain. That doesn't mean that they are brains, but it means that in terms of raw processing, they can process bits as fast as a brain can. So the question is, how far behind that is the development of a machine that's as smart as we are?

The fact that we can't easily foresee clues that would betray an intelligence a million millennia farther down the road suggests that we're like ants trying to discover humans. Ask yourself: Would ants ever recognize houses, cars, or fire hydrants as the work of advanced biology?

Humans have existed only for the last 0.001 percent of cosmic time. All of which says that - unless the Homo sapiens brain is the one-and-only instance of cogitating machinery - nearly all the intelligence that's out there is beyond our level. And that intelligence is more than just a little bit beyond.

Is E.T. out there? Well, I work at the SETI Institute. That's almost my name. SETI: Search for Extraterrestrial Intelligence. In other words, I look for aliens, and when I tell people that at a cocktail party, they usually look at me with a mildly incredulous look on their face. I try to keep my own face somewhat dispassionate.

'Dating Game' wasn't social commentary, political analysis, Shakespearean-level drama or even blunt-force comedy. It was just the televised equivalent of meeting someone at a bar. But it appealed to our most basic Darwinian instinct: selecting a good mate. You can't go wrong when a show's premise is hard-wired into human DNA.

The stars look the same from night to night. Nebulae and galaxies are dully immutable, maintaining the same overall appearance for thousands or millions of years. Indeed, only the sun, moon and planets - together with the occasional comet, asteroid or meteor - seem dynamic.

The math is dead simple: it seems that the frequency of planets able to support life is roughly one percent. In other words, a billion or more such worlds exist in our galaxy alone. That's a lot of acreage, and it takes industrial-strength credulity to believe it's all bleakly barren.

Neil Armstrong was no Christopher Columbus. In most respects, he was better. Unlike the famous fifteenth century seafarer, Armstrong knew where he landed. He also spent his time in public service, not in jail, and his passing was marked by world-wide encomiums. He ended his days as a celebrated explorer rather than a royal inconvenience.

While human space travel is daunting, machines - with their indefinitely long lifetimes - could travel the galaxy. It might make little difference to them that bridging the distance from one star to the next could take hundreds of thousands of years or more.

The principal reason for the universe's poker face is that its constituents are far away. Stars careen through space, and galaxies spin at speeds thousands of times faster than a jet plane. But given their distance, you'd need the patience of Job to notice much change in their appearance or position.

The cosmos is three times as old as Earth. During most of creation's 14 billion year history, our solar system wasn't around. Nonetheless, the early universe still had the right stuff for life, and contained worlds that were just as suitable for spawning biology and intelligence as our own.

The Moon stabilizes Earth's obliquity. Well, almost. The tilt actually varies between 22 and 24.5 degrees - and the variation is enough to induce such environmental inconveniences as the occasional ice age. Without the Moon, it might be much worse.

The math is dead simple: it seems that the frequency of planets able to support life is roughly one percent. In other words, a billion or more such worlds exist in our galaxy alone. That's a lot of acreage, and it takes industrial-strength credulity to believe it's all bleakly barren.