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By Seth Shostak

Is Earth being visited by space aliens? A lot of people think so, although few of them are scientists. Professional researchers are not easily persuaded by eyewitness testimony, blobby photos or claims that evidence for itinerant aliens has been stashed away by a paranoid government.

Put more succinctly, academia doesn’t put a whole lot of credence in the incessant claims that some of the thousands of UFOs sighted every year are actually alien craft. But at least one scientist has recently gone on record suggesting that the clipboard-carrying crowd should be a little less sure.

That scientist is Silvano Colombano, a computer expert and roboticist at NASA’s Ames Research Center in the heart of Silicon Valley. He was a presenter at a conference about new approaches in the search for extraterrestrial intelligence (SETI) held earlier this year at the SETI Institute in Mountain View, California. Colombano says the skeptical attitudes of most researchers might be too cramped. They could be throwing the infant out with the bath water.

He cited this example: If you approach your favorite astronomy professor and see what she has to say about interstellar rocketry, chances are she’ll roll her eyes. The energy required to accelerate an Enterprise-size starship to near the speed of light is greater than can be wrung from all the remaining fossil fuel on Earth. Fast travel between the stars is incredibly difficult (or impossible), she’ll say. So forget the idea of little gray guys piloting saucers in our airspace. Their home planet, wherever it might be, is just too far away.

But there’s an assumption here, as Colombano pointed out. Namely, that the aliens are biological, and require a fast transit between star systems to forestall dying en route. This small problem, after all, was the motive for Star Trek’s (fictional) warp drive.

However, there’s a fix for that: Get rid of intelligence that dies. Anyone who’s not a total troglodyte knows that artificial intelligence is on the way. By the end of this century, it’s possible that the smartest thing on Earth will be a machine. Since most star systems are billions of years older than our own, you can be sure that any clever inhabitants out there have long ago relegated biological brains to the history books, and are homes to very smart, and possibly very compact, thinking hardware.

As Colombano says in a new paper, “Given the fairly common presence of elements that might be involved in the origin of life… it is a reasonable assumption that life ‘as we know it’ was at least a common starting point, but our form of life and intelligence may just be a tiny first step in a continuing evolution that may well produce forms of intelligence that are far superior to our and no longer based on carbon ‘machinery.'”

Well, an obvious advantage of non-carbon machinery is that it needn’t be cursed with a short lifetime (this despite the experience you may have had with your laptop). Truly sophisticated devices can be self-repairing. Consequently, they can go great distances simply because they’re in no hurry to get to their destination.

This has a profound consequence. Earth has been trundling around the sun for more than 4 billion years. Even at the modest speed of a NASA rocket, that’s more than enough time to get to our planet from anywhere in the Milky Way Galaxy. If the passengers don’t mind spending billions of years in a middle seat, they could to it. Compact machines wouldn’t take much space, and wouldn’t groan at the long transit time.

So, what should we conclude? Clearly, it’s possible that some alien intelligence has decided to come to our solar system and check Earth off its bucket list. Doing so doesn’t violate physics. This might have happened 100 million years ago or a billion years ago, and we wouldn’t know.

But the more appealing thought for many people is that we’re being visited now. Of course, a scientist would consider such a suggestion of interest only if it could be corroborated by observation. Bright ideas are nice, but evidence rules.

So Colombano suggests that massive computers be applied to finding such evidence among the many thousands of UFO sightings. Maybe there’s a gold nugget in all those reports. As Colombano points out, if there’s something to be discovered, we won’t find it unless we look.

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