i agree!
----- Original Message ----- From: "Michael Turner" <[EMAIL PROTECTED]>
To: <europa@klx.com>
Sent: Monday, February 07, 2005 1:57 AM
Subject: Re: Active SETI Is Not Scientific Research - Europa relevance
What if most life in the universe evolves on worlds like Europa? I've called this the Common Europa Hypothesis.
Gas giants appear to be abundant. Water appears to be abundant. The main energy source for biochemistry in the universe might be tidal forces rather than stellar input. The main form of space radiation protection might be thick layers of ice, not magnetic fields and atmospheres.
Civilizations may become quite developed long before they discover the existence of space per se. They may rely on wired or optical fiber communication or something like it, in preference to radio communication, given how poorly radio signals travel through water. And when they finally penetrate to the ice surfaces of their worlds, having long since inferred the existence of a surface, and much empty space beyond it, they may also have long since hypothesized the Killer Star, and would avoid broadcast radio communications on the surface to the extent possible - not hard, given that it would probably be mainly a curiosity technology to them in the first place. The only Killer Star scenario they might be worried about would be some alien "defense" system that seeks out and relativistically bombs all ice-covered ocean worlds - many more candidate targets than would be revealed by assuming Rare Earths out there, with possible threats narrowed down by picking up radio wave broadcast activity. A Rare Earth is far more vulnerable to total ecosystem destruction by relativistic bomb impact. A world like Europa is protected by miles of ice. It would take many more bombs, and much larger bombs, a total shotgun approach. A world like Europa might also be more resistant to nanotech infections, given the enormous energy requirements for penetrating the ice shield.
Also, a world like Europa will have a vestigial atmosphere at best, and will probably rotate synchronously around its gas giant, so it might offer a better surface for hosting SETI efforts than the surfaces of planets like Earth. Their "space elevator" might largely amount to building a strong tube going to the surface. And they will, of course, look for life somewhat more like their own, on worlds somewhat like their own.
I think it's not unreasonable to suppose that they may be more likely to engage in their own Active SETI. After all, SETI presupposes Active SETI to a great degree. And they'd be facing less Killer Star risk, and have less reason to believe that the risk was significant in the first place.
If worlds like Europa are common, quite a few systems might have more than one. If intelligent, spacefaring life evolves on one such world, their first exploration target is likely to be the others in the local planetary neighborhood. With enough of a long-range view, they might forgo "Europaforming" the others and set up Active SETI on the other Europoids (maybe preferring one orbiting another gas giant, if there's another one orbiting their own), as bait for anyone's Killer Star defense system. If, after some decent interval, say a millenium, the decoy world still hasn't been relativistically bombed, they might reasonably assume that nobody is going to do it, and broadcast a signal to any neighbors saying that the coast seems to be clear. (Of course, that signal has to be credible. There's always a leap of faith somewhere, isn't there?)
Finding out whether there's life on (in?) Europa, and seeing how far it has developed, what the intrinsic limitations might be, could tell us a lot about how to conduct Active SETI safely. So might a focus on trying to find other likely Europas elsewhere, to see if they are common. First contact might be an expression of disbelief - "You live on the OUTSIDE of your planet, and breathe gases? You're the first world in 50 communicating so far to have intelligent life much different from ours. Only in science fiction ...."
-michael turner [EMAIL PROTECTED]
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