A follow up to Life as we don’t know it:
‘Nomad planets’ could carry bacterial life
According to the article there might be as many as 100,000x ‘nomad’ planets for each visible star which, if true, would almost require that a number of them harbor some sort of life.
As mentioned in my earlier post, in an infinite universe even events with very low probability must have happened an infinite number of times. According to our current understanding of astrophysics our universe is ‘only’ 13.5 billion years (and our solar system 4.5 billion years old) so quite a far bit from infinite, but still a really long time. If life is as common and ordinary as I believe (meaning just about anywhere there is water, thermal gradients and a certain minimum variety of chemical compounds results in some sort of life and from thence to evolutionary development) then we aren’t talking about any sort of vanishingly small probability that would require an infinite universe, we are talking about something that might happen dozens, if not thousands, of times in each solar system. Now, if life is indeed common, but the probability of intelligent life (giving us the benefit of the doubt ;-)) is very low, as the incidence of life increases so must the incidence of intelligent life. I was watching a show on whales and dolphins last night discussing their intelligence (or rather our ability to measure their intelligence as in my mind there is no question regarding their intelligence) and it seems clear to me that just our planet alone has evolved several intelligent life forms. As I mentioned a bit earlier if octopi and cuttlefish lived longer I figure there is a very high probability that they would have been the technologically advanced race on this planet and probably millions of years ago. Thus, to me it would seem that the paltry single example we have to evaluate has produced several (wildly different) life forms all capable of (or already exhibiting) sentience and intelligence. With our planet as an example I would have to say that intelligence is not rare and while the number of planets that can support multicellular life and have the evolutionary pressures that might produce intelligence could be relatively rare, I would have to say that as the probable incidence of life increases the probable incidence of intelligence increases such that we really have to question why we are not seeing any evidence of such intelligence.
Now, again using our planet as an example, we have at least two intelligent groups (whales and dolphins) that lack the ability to produce any sort of technology that would allow them to communicate off planet. If we were to posit intelligent octopi or cuttlefish, given their very soft bodies and requirement for immersion in water it is easy to imagine a technological society that fails to make any sort of radiation that could be detected off planet and lacks the technological skills to go to space (it is hard to imagine it would be easy to smelt metals under water) might be too much of a challenge for sea creatures. Thus there may be huge numbers of intelligent organisms in our universe that simply lack the ability to communicate past their planet. I am amused by Larry Niven’s Bandersnatch, a species created as both a food and a spy that resorted to selling hunting licenses on itself in exchange for technological tools. What if we monkey tool users ever develop the ability to explore the galaxy? Perhaps we can sell our technology to other species in exchange for knowledge.
Of course it would seem highly probable that if life is almost inevitable and intelligence is therefore fairly common it would seem that there should still be a number of species technologically advanced enough to communicate solar system to solar system. Why haven’t we heard from them? Perhaps there is some benign Federation that blocks access to undeveloped systems until some technological hurdle has been overcome. Perhaps the energy necessary to communicate and the lag between messages is such that very few species with the skills bother (most of our attempts to communicate outside our solar system are almost laughable).
Then again, perhaps there is no solution to faster-than-light (FTL) travel (all Star Trek wishes to the contrary) and there is no way to visit with other solar systems in a meaningful amount of time, which might be just the sort of disincentive that would keep any species from undertaking the organized effort communicate.
On the other, other hand (or on the gripping hand) perhaps we are being observed and the observers don’t want to communicate. I can easily imagine that if we had very long life spans (or develop that ability as I believe is feasible in the next 50 years or so) we could tolerate sending out probes that would report back after making the long sub-light speed journey to adjacent solar systems. With enough pre-programming I don’t see the requirement for two-way communication with the probes, they might only report back, so we might be being monitored by a plethora of different technological species even as I write this. If FTL travel really is impossible then there isn’t much concern with alien species attacking us as the effort necessary to travel between stars has to be so huge that it is probably more economical to just invest that energy in becoming self sufficient where they are. As I describe in my Trillions paper, by making use of a Dyson sphere we could support 440 quintillion people simply using the Sun’s energy. Surely any species technologically advanced enough to build craft capable of traveling between solar systems would also be advanced enough to maximize their utilization of their own system, so it seems to me that without FTL we have nothing to worry about. By taking advantage of objects in the Kuiper belt or even the Oort cloud it should be possible, presuming enough nuclear fuel is available (and if we ever sort out economic fusion that is a certainty) to completely populate a given solar system to the point that the measurements will be in millions or even billions of quintillions.
I would think, though, that with the energy situation resolved and such a huge population scattered throughout a solar system, that enough individuals would be interested enough in communication attempts that we would still see some signs. Perhaps there is some ‘Macroscope-esque‘ technology we are lacking that keeps us from communicating.