20 JULY 2006
ommunicating with extraterrestrial
civilizations has always been a far out idea.
And after decades of trying, the search for signals from extraterrestrials has produced precisely no breaking news. There have been no e-mails from Vulcans, Klingons or Ferengi. No sign of Klaatu and Gort. The X Files is still fiction, and E.T.'s home phone number remains unlisted.
Consequently
the famous question posed by the physicist Enrico Fermi in 1950 remains
unanswered. "Where is everybody?" he asked. If the galaxy is teeming with
sophisticated aliens, we should have heard from them by now.
A new response to the Fermi Paradox comes in a recent issue of the journal New Astronomy. The aliens, like the truth, may be out there -- but perhaps are so far out that there's no hope of receiving even a text message.
Fermi thought there just weren't any aliens, but today there's more reason than ever to believe in E.T.'s existence. Nobody knew back then that planets were so plentiful -- about 200 distant planets have been detected, just in the nearby regions of the galaxy. And evidence now suggests that life can originate fairly rapidly, given a planet in a comfortable climate with the necessary raw materials. Furthermore, recent analyses show that planets probably began to form billions of years before the Earth appeared, so most other planets would probably host more advanced civilizations.
"Fermi's paradox is not only still with us more than half a century later, but . . . it is more puzzling and disturbing than ever," say Milan Cirkovic, of the Astronomical Observatory of Belgrade, and Robert J. Bradbury, of the Aeiveos Corp. in Seattle.
In their New Astronomy article they offer a novel solution to the Fermi paradox, relying on the "intelligence principle" proposed a few years ago by NASA historian and astrobiologist Steven J. Dick.
Cosmic
evolution as depicted by Ames Research Center, NASA.
Dick argued that estimating the likelihood of alien life requires more than knowledge about the physical universe and biological evolution. Cultural evolution also comes into play. "We may in fact live in a post-biological universe, one that has evolved beyond flesh and blood intelligence to artificial intelligence that is a product of cultural rather than biological evolution," Dick wrote. And he proposed that the guiding principle of culture is the desire to perpetuate and improve knowledge and intelligence.
While current events on planet Earth argue strongly against the success of this cultural imperative, let's suppose that it works on other worlds. The implication is that biological civilizations will ultimately morph into machine worlds, since computers are so much better than people at processing information and exhibiting intelligence (assuming some substantial advances in software and hardware).
Consequently, Cirkovic and Bradbury say, astrobiology should adopt a "digital" perspective. "After a particular threshold complexity is reached, the relevant relations between existent entities are characterized by requirements of computation and information processing," they write.
In other words, while humans have passed from agricultural to industrial to post-industrial civilization, E.T. has gone on the to the post-biological age, replacing messy brains and bodies with state-of-the-future-art computer chips.
Now here's the rub. Computing requires energy (in practice, although not in principle), and so it's a problem to get rid of the heat that computers generate. To compute most efficiently, you'd want the coldest environment you can find. Therefore, say Cirkovic and Bradbury, extraterrestrial civilizations aren't around because they've all moved out of the neighborhood. They've migrated to the outer reaches of the Milky Way galaxy, the coldest environment imaginable. Just as the Earth occupies a "habitable zone" around its star, the outer edges of the galaxy offer the ideal "technological zone" for artificial brains.
It doesn't matter if aliens have become computers or merely own computers or are hybrid biocomputers. They'd seek the best place to compute (and to survive, they'd also want to get far away from those pesky exploding stars). Therefore if you want to find E.T., you should look about 50,000 light-years from the galaxy's center (the Earth isn't much more than half that far out). Radio reception is lousy from such distances, so it isn't surprising that searches for radio messages by the SETI project have failed.
"We conclude that the conventional radio SETI assuming beamed broadcasts from targets -- selected exclusively on the basis of the old fashioned biological paradigm -- within the vicinity of our Solar System is ill-founded and has minuscule chances of success," Cirkovic and Bradbury write.
From this perspective, aliens wouldn't send any signals our way, anyway. They probably left town more than a billion years ago, when Earth's collective intelligence was still on the amoeba level. Even if aliens are watching now, they'd just see the precivilized populations of 50,000 years ago. (If they saw what we're up to now, they'd think we're even dumber).
Of course, the whole idea could be all wrong, and aliens could be everywhere, just hiding from us. Still, the idea of a post-biological intelligence does have its attractions, particularly for transgalactic travel. In terms of the fuel needed to move masses of humanity, it's prohibitively expensive to transport a planet's population across space. But if everybody's brain is deposited in nanocomputers, intelligence could then travel freely throughout the cosmos, with no blackout dates.
And if such a superintelligence could go anywhere it wanted to, it's not very likely that it would want to come here.
E-mail: tsiegfried@nasw.org
