March 14th, 2009
Not every scientist has an interest in science fiction or anything resembling the ability to think like a science fiction writer.
I was reminded of this again today in regard to this story about how to focus SETI searches.
Basically, the idea is that it is easier in principle to find and characterize Earth-like planets when you can see them eclipsing their system’s star. Therefore if we want to talk with ETIs, we should be targeting our searches in the plane of the ecliptic. “Plane of the ecliptic” is just a technical term for the directions in space that would see us eclipsing the Sun. The aliens living in star systems in the plane of the ecliptic, so the reasoning goes, would then be the ones most likely to have spotted us and be trying to communicate with us.
Maybe a teeny-tiny bit more likely, but overall a dumb reason to restrict searches in my opinion. (Somehow the article I linked to talks about using the idea to “broaden” searches, but that’s just bad reasoning or writing, in my opinion. The only way to use the idea is to restrict searches.) Let me explain why I think the idea isn’t very good or logical, setting aside my scientist cap for my science fiction writer cap.
We are at the dawn of the era of discovery of exoplanets. We haven’t quite found Earth-like planets yet, but we’re approaching the technology and time required to do so. We’ve gone from no exoplanets known 15 years ago to many hundreds now, and the eclipse-finding technique is just the latest step. We’ll be able to image Earth-like planets around other stars in the relatively near future, and in all likelihood, a century from now barring some catastrophe in our civilization, we’ll have the technology to do a whole lot more. A big enough space telescope could do the job of spotting Earth-like planets in principle, whether or not they are in eclipsing systems.
So, the only way I think this makes any sense as a strategy is if the aliens are essentially at the same technology level we are, and not a century or more advanced.
If you think that high-technological civilizations are short lived (centuries or less), the chances of finding one anywhere nearby is tiny, let alone in the highly-restricted plane of the ecliptic.
If they’re long-lived (much longer than centuries), they will have the technology to spot us whether or not we are an eclipsing system as seen from their world and we should be looking everywhere for their signals, if in fact they are sending us such signals.
This argument can be quantified, which would take time away from things more important to me that this flawed proposal, in order to say exactly how small the benefit would be from adopting this strategy, if in fact there is any benefit at all. It is not at all clear to me that it is one. In fact, I will go as far to say that I think the study is wrong. If civilizations are long-lived, we’d be idiots to restrict searches as there are a lot more systems outside the plane of the ecliptic than in it. There would only be a benefit for short-lived civilizations, which would be unlikely to be there and broadcasting anyway, and then it becomes a contest between the exact time-frame a civilization has advanced technology versus the number of stars in and out of the plane of the ecliptic.
Here is the original paper, by the way. The author seems to want to have it both ways, assuming an optimistic million-year lifetime for a civilization but claiming that finding Earth via direct imaging is unlikely for anyone except very nearby ETIs. The million-year lifetime, however, suggests that nearby ETIs are likely to exist, and that they are likely to have technology hundreds of thousands of years more advanced than our own. Hundreds of thousands of years. And only “nearby” ETIs are going to bother to do anything but eclipse studies to find Earth?
OK, he does try to respond to my point, even though his search restriction only improves search efficiency by a factor of “16-40.” Damn small gain to weigh against the competing issues. His counterargument relies on the assumption that it will take the aliens “hundreds of thousands of years” to find Earth via proper motion or other sorts of studies, which is ridiculous.
It’s like he can’t imagine technology or resources very much more advanced than our own, or, when he does, still claims eclipsing is easier and we should neglect searching 90+% of the sky.
Remember, according to some we’re supposed to have the Singularity in a couple of decades and get superpowers. I think a civilization just a thousand years more technological advanced than ours will not have any problems finding us if that’s what they want to do.
OK, done picking on a guy thinking in interesting ways about an interesting problem. He’s been very quantitative about some easy things, and neglected the hard questions like what is the lifetime of a civilization and would it really be hard for a much more advanced civilization to find us without eclipses. “Hundreds of thousands of years” seems like a laughable strawman to me. I mean, we went from an era 50 years ago where people got PhDs for studies of samples of a few objects, to today when people do projects studying millions of objects. The number of stars in the galaxy does not seem daunting to me in the face of advancing technology.
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Very good blogitem, Mike. May I have your permission to post this as a Guest Editorial on The SETI League website? Credit will of course be given, and a link back to your site provided.
Thanks, Paul
(Executive Director Emeritus, The SETI League, Inc.)
Sure. Post away. Glad you found it of interest.
I wonder why we havent found any alien civ so far. Or we do indeed live on an Asimovian galaxy and we are alone on the Milky Way, or (entering sci-fi realm here) it just happens that civilizations communicate in radio and other electromagnetic frequencies for a brief period of time, before switching to more efficient communication systems necessary when you control several star systems. I mean FTL comms. (I said i was entering sci-fi realm)
Another possibility is that, just like humans do war and are also paranoid about it (the possibility of being exterminated by vastly superior civilizations), most aliens in the galaxy, which beings ALSO EVOLVED and thus have animal instincts of survival, etc, start camouflaging and coding their comms thus making it difficult or near impossible for other intelligent life in the galaxy to find them. Every alien civ trying to find others, but hiding themselves from fear of the unknown.
Pure speculation I know, but how can anything be but speculation in this subject?
A few years ago here in Ireland , a fairly high ranking member of SETI gave a lecture at University College Cork about how the search was going .When asked how long the search for intelligent life should continue , this person stated about a hundred years, if after a hundred years no signals were found then it would be proof there was no life in the Galaxy.
When I and several other people in the crowd tried to point out the the nearest planet with life could be either stone age or could be so advanced it no longer uses the frequencies or methods SETI does ( I even jokingly said the nearest world could be full of intelligent plants) what we got was a response that no , no all civilizations must be on the same technological level and then some claptrap about the theory that any civilization that reaches a certain technological level is doomed to destroy itself. I am afraid to agree that for some reason a lot of scientists are limited in their ability to imagine possibilities.
Pretty incredible response.
I’ve seen a number of variations of what you describe myself. I think it’s because most scientists are trained to tear down ideas than construct them, and certain topics require a lot of creativity to reach anything but certain conclusions. For instance, UFOs. I’m skeptical about them being aliens from distant stars, but I don’t claim that they can’t be aliens from distant stars because the energy and time required is simply too much. Too much for us, as humans, with 21st century tech? Sure. Too much for aliens with a civilization a hundred million years old? I totally doubt it. I can see a dozen ways for us to do it on timescales of thousands of years, which is only a long time if you believe we are doomed faster than that. There’s a case, but it sure isn’t provable.
Ok , I read the paper and I will admit I am not the smartest man in the room but surely the answer to this is the answer the man on the street would give and that is space is really , really big , you don’t say there’s no one in if you only checked the outhouse
On U.F.O’S I believe that it is possible , I have a cousin in the R.A.F and as a pilot he has seen things that cannot be explained….however I will Digress and give an example of what they can be .My Father was at a racecourse in Co Wexford back in the Sixties( I am Irish) and he and a group of trainers and riders early in the morning saw a craft land take off and Hover before flying off towards the Irish Sea, The Gardai (The Irish Police) arrived and confirmed it was a U.F.O and said not to ask any more questions.
It wasn’t until ten years later that my father met one of those Garda officers ( now retired) who pointed out without confirming that the R.A.F just happened to have been test flying the prototype of the Harrier Jump Jet that day over the Irish Sea and that it might just have happened to have gotten lost.
JV, some UFO sightings are definitely real and have definitely been experimental military craft, without a doubt. There’s a bunch of related phenomena coming together, and it’s too easy to lump them all together as one thing.
Ah yes but if you read the post ,my dad said it was some sort of craft, it was the Gardai who used the cover of U.F.O and that is the problem , if you say you believe in Alien life that’s fine , if you say you believe in the possibility of manned Alien spacecraft, you will be lumped into the same group of people who claim Jesus was a spaceman , Area 51 and Hillbillys who claim to have had weird sexual experiments carried out on them!(The Question is would we really want to communicate with any species that gets a kick of having sex with Hillbillys?) But those who deride loudest again tend to be in the scientific community.Until you point out that if the Space Shuttle exsists , why is it so hard to believe that alien intelligence would be incapable of doing the same?
Anyway I have written too much, just saying what you wrote was intelligent and insightful.
Thanks, you too. And the “careers” of people like Paris Hilton and Britney Spears, with exclusive interviews and TV shows, indicates that we as a people are very interested in communicating with aliens that get a kick out of having sex with Hillbillys.