An interesting story on Seth Shostak’s recent appearances in Athens, OH ran today in The Athens News. In a pair of talks Shostak, senior astronomer for the SETI Institute (Mountain View, CA), explained to a general audience why he thinks extraterrestrial life is out there. He even gave a timeline for its discovery: within the next two dozen years (he went on to bet each member of the audience a cup of Starbuck’s coffee on the proposition). Each SETI experiment, Shostak added, gathers more data than all the previous ones combined.
Deep in the article are two Shostak suggestions for extending the SETI search. First, focus on the same area of sky for longer periods of time, instead of today’s common practice of looking at a star for a few minutes and then moving on. Keep a longer gaze and look for signals of short duration that may repeat every few hours or days.
The second tactic: work harder on binary systems. These may contain technological civilizations that have explored both sides of their twin solar systems (inevitably, Centauri A and B come to mind). If two members of a binary system line up properly from our vantage point — and if the two systems are talking to each other — then there is a possibility for detecting their powerful, tightly focused communications.
Centauri Dreams‘ take: Believing that technological civilizations are rare in our galaxy (and elsewhere, for that matter), I doubt either of these strategies will succeed. But I’m all for SETI proponents who say we won’t know until we try. If ever there was an argument I would be happy to lose, it’s this one, but I’ll let someone else take Shostak up on that two dozen year bet.
“Deep in the article are two Shostak suggestions for extending the SETI search. First, focus on the same area of sky for longer periods of time, instead of today’s common practice of looking at a star for a few minutes and then moving on. Keep a longer gaze and look for signals of short duration that may repeat every few hours or days.”
Um, doesn’t this contradict with his opinion of Loeb’s proposal? I would think that these intermittent signals are consistent with leakage and amenable to Loeb’s long-term integration method.
Note that I did not read Shostak’s article, so I am basing this comment on your description of it.
I had the same thought, Ron, though I suppose that by specifying short duration, he could be talking about a different kind of beacon as opposed to leakage. Still, it does seem like a less than likely scenario for an intentional, targeted signal.
I guess the binary hypothesis could be possible. I’d hate to think of how many times evolution would have “reset” upon planets in such systems. Consider the dance of a binary or trinary system and what it would do to the stability of the outer system materials. I would think cometary bombardment would be very high and continuose.
Actually, stable orbits turn out to be quite possible in binary systems, something we used to think couldn’t happen. Even Alpha Centauri turns out to have stable orbits around A and B out to Mars-like distances; the outer systems are another story. Greg Laughlin is doing lots of work on the Alpha Centauri situation these days, including the effects of Proxima on bombardment of possible inner worlds, thus delivering volatiles. Very interesting situation!
Putting an exact timeline on the discovery of extraterrestrial life is a risky proposition. Exobiologists are still debating and arguing over the exact true nature of the life hunting experiments from the Viking Lander Missions 30 years ago.
While a definate, undeniable signal from an extraterrestrial source would be definate proof of another intelligent species in the universe other than humanity, it should be noted that August 15, 2007 will be the 30th anniversary of the WOW! Signal – discovered by Professor Jerry R. Ehman at the Big Ear Radio Telescope at Ohio State University. Even Professor Ehman has flipped-flopped on what the nature of the WOW! Signal is over the years.
The basic flaw in Professor Shostak’s binary detection method is that he’s assuming ETs are going to exhibit non-human behavior when it comes to communication. Some ETs who colonize another habitable planet in a binary system may not speak to each other. Those ETs who colonize another planet in a binary system may be escaping from an intorrelable situation on their homeworld and may cut off all ties completely.
>If two members of a binary system line up properly from our vantage
>point — and if the two systems are talking to each other — then there
>is a possibility for detecting their powerful, tightly focused
>communications.
In 1960 Shklovskii commented ironically: “Three civilizations on one straight line ?”