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There is a disconnect between these two statements: "No alien civilizations have substantially colonized our solar system or systems nearby. Thus among the bil
by Udo 12y ago
There is a disconnect between these two statements:
"No alien civilizations have substantially colonized our solar system or systems nearby. Thus among the billion trillion stars in our past universe, none has reached the level of technology and growth that we may soon reach."
While the article is in a way all about exploring that disconnect, it's a bit strange to find it written down so explicitly in the conclusion. We can ascribe a very high level of confidence to hypothesis that neither our own nor any of the directly neighboring star systems have been colonized. But to postulate that therefore the universe has not yet produced a civilization as technologically sophisticated as our own is still a non-sequitur, at least in my opinion. The article also makes a lot of assumptions (it has to!), some plausible, some seemingly arbitrary, which might in the end not be important factors at all. For example, any consideration about radio communication must be on very shaky grounds, in particular when charting the absence of it.
The reason why we're not seeing alien neighbors or predecessors (which would be "neighbors" in time), might well be a combination of factors. While we can exclude certain scenarios, such as a cloud of Von Neuman Probes eating the galaxy, it still leaves room for a lot of little factors that can change the galactic stage for us in a fundamental way - especially if they work in conjunction.
For example, the average duration of the technologically recognizable phase a civilization goes through may be smaller, and there may well be less of them than expected. In addition, willful avoidance or isolation may well play a role; the zoo hypothesis is an extreme example of this, but in a sparse cosmos the measures you have to undertake in order to isolate an emerging civilizations become less heroic.
It's also worth mentioning that we ourselves are not past the Filter by any means. In fact, as time progresses, it seems to become less likely we'll ever move off the Earth as an exclusive habitat. Part of this is due to psychology, we could have made it happen by now but didn't. The best bet at becoming an interstellar civilization right now seems to be to wait until we're pure computer systems, unburdened by aging and the passage of time, but that development, too, might end up being something we never elect to actually pursue.
Luckily, this whole thing is a mystery we can solve over time, just by gathering data about what's out there.
- Retra 12y agoThe 'soonness' of our interplanetary colonization is really not safe to assume. The obstacles to self-sustaining life on other worlds are not insignificant -- in fact, they are the explanation for why there is no life there to begin with.
- exratione 12y agoThe problem is that if you exclude the scenarios that obviously didn't happen you are still left with no likely scenarios given the present consensus understanding of biology and physics. The timescale for megascale engineering to occur throughout our galaxy as the result of the launch of one megascale engineering minded self replicating probe is small (1 million years) in comparison to the age of the galaxy (13 billion years). It is unlikely that we are sitting here while someone else is in the process of doing it; that's not the scenario to focus on. All it takes, remember, is one small group in one sufficiently advanced culture to start this going. Some (post)human group will clearly do it at some point if we as a species continue. Why hasn't someone already done it, where "it" is visibly engineer the totality of the future light cone? The problem is less one of why don't we see Dyson spheres and other similar type II projects within a few hundred light years of our position, and more one of why do we see no obviously altered galaxies among the hundreds of thousands cataloged to date. At this scale the zoo hypothesis looks stretched, and the simulation argument begins to look more plausible.
- thesteamboat 12y agoYour comment sparked an interesting question in my mind: If some entity is trying to colonize in every direction at near the speed of light what is the expected gap time between the light of the actions reaching us and them reaching and colonizing us? A partial answer to the Fermi paradox by appeal to the anthropic principle: there is a very small fraction of time between being able to observe an alien species and being consumed by it.
- Udo 12y agoGood points, but I'd like to offer some counter arguments to the megascale engineering idea, hopefully without sounding too pedantic. The need for megascale projects is not as obvious as it's sometimes made out to be. There might well be reasonable limits beyond which the maximizing of habitat space and energy consumption tapers off in utility. Even if our civilization continues on its present course, it's not certain that we will get to the point where we (or some of us) feel the need to change the face of the galaxy. If you go one step down from the galactic stage, the detectability of solar system-scale megatech is also open to debate, especially as you move beyond a couple hundred light years from here. You're right of course when you say all it takes is one civilization (or even one member of a sufficiently advanced society) to undertake projects that are liable to make all kinds of strange phenomena appear in our night sky. But the number if beings capable of doing so on a whim, multiplied by the chance they'd be interested in such things, might be very very small without breaking any of our current expectations about biology and physics. Finally, I'd like to address the simulation argument. There are two extreme ends of the simulation scenario spectrum. At the one extreme, we're talking about an artificial reality made especially for us, humans. This would be the popular "Matrix"-style simulation. No scientific argument I've heard so far makes it a convincing model for the reality we live in, except as a possible explanation for the Fermi paradox. At the other end of the spectrum, we have a full simulated universe. It's hard to argue for or against that notion, simply because either way it fits with our observable reality. The catch is of course that it's a neutral proposition with no impact on us at all. This variant does not offer any explanation for the Fermi paradox. As I see it, the simulation argument as pertinent to the Fermi problem offers two options, neither of which are intellectually appealing: one is a borderline-untenable just-so make-believe world where all rules are an illusion and anything can happen, and the other one is virtually undistinguishable from our "normal" world, up to and including an absence of any obvious explanation for the Fermi paradox.