The public has shown a tremendous interest in astrobiology, but I suspect a large part of this interest is with the implicit assumption that we’re all searching for this guy:
Not the guy pedaling the bike… The other guy.
At some level, most astrobiologists are working towards finding or constraining the possibilities for advanced life beyond Earth that we could one day have a conversation with. For example, I often think it’s useful to place astrobiology research into the context of the Drake equation, which is a tool to guesstimate the number of advanced civilizations in the galaxy. (Quick aside: I think that’s the main thing this equation is useful for: placing research into that specific context.)
The truth is that only a small portion of astrobiology research is focused directly on the search for advanced civilizations. And I think that’s the proper allocation of our resources. Until a short time ago, we had very little idea of where to look. And the most easily-detected signals would originate from huge satellite dishes that may not always be pointed our way. Plus, we must be listening to the right “channel” to receive or intercept any communications from another civilization. To summarize, to catch a signal we have to be listening in the right direction at the right time be tuned to the right channel. That’s a LOT of parameter space to cover.
The difficulty of the search is why I never really thought SETI* (the Search for Extraterrestrial Intelligence) was worth directing significant funds towards. However, that has changed over the last 10 years, and especially over the last 2-3. With the Kepler spacecraft in orbit, and with significant improvements in ground-based search strategies, we’re finding planets with properties that are increasingly Earth-like. And despite minor quibbles over some of the definitions of habitability, I think everyone agrees the objects found in the early parts of this decade have waaaay more potential to host civilizations than the ones previously discovered.
Those discoveries have significantly decreased the main challenge SETI has always faced. SETI activities can now focus on specific stars that are known to harbor planets in or near the habitable zone, or that have planetary systems that appear reasonably similar to the one we live in. And that’s going to continue getting better. I think the chances are quite high that at some point in 2013 Kepler and/or the ground-based observing community announce the presence of a planet that inarguably has the potential to support complex life. And I also expect that to be just the first of many such discoveries. Over the next decade, we should find – and hopefully begin to study – many more such planets.
I bring this all up not because it’s some epiphany I had that I wanted to share… but because this exact kind of search was recently in the news. Researchers from the SETI Institute** UC Berkley just announced the first set of results from one of these directed searches. The results were negative – otherwise you would have heard about this a LOT over the last week.
And here’s the great part – this is now being done as science acting on a fairly narrow hypothesis amenable to repeatable testing. There were no signals from their target stars during their search window. Why not? The simplest explanation is that there are no interstellar communications arising from any of those planetary systems. But maybe they’re communicating at a different wavelength. Maybe they only send us a signal once every 10 years, or 100 years, or π years. The point is that we can double-back and test these alternate explanations for the lack of a signal… something that was daunting (if not impossible) when the search had to cover the whole sky.
In my mind, that’s the right way to SETI.
An earlier version of this post mistakenly credited the SETI institute for this work. SETI Institute researchers were collaborators on this project, but it was led by scientists at UC Berkley. (Somewhere in the depths of my absent mind, I knew this, but forgot in a rush to get this posted before my laptop battery died earlier today.) The article I had previously linked to incorrectly attributed this, and I spread that info. Sorry ’bout that!
* For the most part in this post, I’m talking about SETI “the activity,” not SETI “the institute.”
** Here, i’m talking about SETI “the institute.”