SETI Ponders the Silence
Since no clear signals from space aliens have yet arrived in 40 years of looking, SETI thinkers are asking why. They’re coming up with a variety of explanations. Here are three possibilities from recent articles.
- Too Soon to Tell. Seth Shostak of the SETI Institute, writing in the September cover story of Astronomy Magazine, isn’t ready to call it a failure. He gives the standard SETI response that we’re unsuccessful so far because the search has only just begun. Considering the number of stars to search, it may take centuries to cover the sky adequately. Sagan, Drake and others knew this and have been saying it all along. But new technologies are rapidly accelerating the search for extraterrestrial intelligence, and could give us an answer within 20 years. So remain optimistic, he says, and stay tuned to the stellar radio dial.
- Narrow Window. Frank Drake, SETI pioneer and author of the Drake Equation, surmises that the parameter L (lifetime of an intelligent civilization) may be the most telling factor, but it needs to be qualified by our recent human experience, according to an article on New Scientist August 4. Detectability was predicated on an assumption that radio “leakage” from earth would be visible to aliens, and vice versa. Our own leakage has dropped significantly, however, since cable TV and direct-broadcast satellites became popular. This means that when the last “I Love Lucy” broadcasts reach the aliens watching from a distant star, the earth may appear to go silent. The bad news is that maybe advanced civilizations only have a narrow window of time during which they would broadcast radio toward us, either on purpose or inadvertently through broadcast leakage. The good news is that SETI researchers don’t necessarily have to be discouraged at the silence. Perhaps a switch to optical SETI (searching for laser beacons) can fill in the gaps.
- Look Up, Look Down. Aussie astrobiologist Paul Davies, never shy about proposing ideas “at the extreme end of the spectrum of speculation,” has a new detection strategy. If aliens were trying to send us a message, radio would be a wasteful method, he claims in an August 10 piece in the Sydney Morning Herald. Why would aliens keep radio beacons going for centuries with little hope of them being detected? Leaving artifacts like plaques or big chunks of metal, on the other hand, would incur horrendous shipping costs, with no guarantee they would survive millions of years of erosion or burial. Get ready for his surprise solution, as he role-plays the alien messengers in council:
The ideal solution would be to encode the message inside a large number of self-replicating, self-repairing microscopic machines programmed to multiply and adapt to changing conditions.
Fortunately such machines already exist: they are called living cells.
Although this sounds uncannily like an argument used by Intelligent Design scientists,* Davies means something very different. That he’s not talking about evidence for a Creator God is clear from his next sentence: “The cells in our bodies, for example, contain genetic messages written by Mother Nature billions of years ago.” Like any good Darwinist, he believes cells and their genomes evolved in the usual Darwinian way. But, he speculates, aliens might have left messages in the so-called “junk DNA.” (See 06/03/2004 headline). He proposes, therefore, that SETI researchers should turn their attention to hidden messages in the large, non-coding regions of our own genomes: “There is plenty of room there for ET to etch a molecular message without damaging any vital genetic functions,” he claims, particularly because “scientists in the United States have discovered whole chunks of human and mouse junk DNA that seem to have remained virtually unchanged for tens of millions of years.” (See 05/27/2004 headline.) Those regions would be good places to store messages, he thinks, kind of like how we encoded messages in radio beams and on the Voyager record. What about the shipping cost? His tale gets curioser and curioser. Since viruses can insert genes into a host cell, “An alien civilisation could, for negligible cost, dispatch tiny packages across the galaxy, loaded with customised viral DNA.” We might just find that “The truth is inside us.”
*ID scientists have argued that if intelligence can be detected in coded messages from space, why cannot intelligent design be detected in coded messages within living cells? For example, see “Is Intelligent Design Testable?” by William A. Dembski on www.arn.org.
Welcome to the SETI Bizarre (intentional spelling), where a rainbow of imaginative speculations is colorfully displayed and dished out on the cheap. The Bizarre is popular because of all the free advertising provided by the gullible media. Isn’t science thrilling? Too bad those church-going fundamentalist types operate only on faith.
Remember an old childhood prank? A smart aleck walks up to a gullible kid and gets him to follow his hand: “Look up. Look down. Look at my thumb. Gee, you’re dumb.” Try it on the next astrobiologist you meet, except with the following interpretive expansion: Look up (at the heavens, the anthropic universe, and the cosmic order). Look down (at the earth, the lithology, the biosphere, and the improbable convergence of parameters that makes life possible). Look at my thumb (biology, anatomy, physiology, and all the molecular machines, organs and integrated systems that make muscular motion and vision function nearly instantaneously, and the consciousness that gives sense to the observations). Astoundingly, you appear philosophically challenged and willfully ignorant (if you think this all just happened by chance). Which leads to a suggested revision of the Davies proverb: not, “the truth is inside us,” but rather: “the thumbprint of the Truth is inside us.”