rfmcdonald | [LINK] "Dyson Spheres Make the Fermi Paradox Worse" (Reply)

t his weblog, futurist Anders Sandberg links to an interesting if unsettling presentation to Oxford University's Physics department by one Stuart Anderson, co-authored by Sandberg himself, that suggests that the Fermi paradox--"Where are the aliens, they should be here already?"--is much more challenging a question that people have thought. Not just interstellar but intergalactic colonization seems technologically imaginable, making the question of where the extraterrestrials are that much more compelling.

The YouTube abstract:

The Fermi paradox is the contrast between the high estimate of the likelihood of extraterritorial civilizations, and the lack of visible evidence of them. But what sort of evidence should we expect to see? This is what exploratory engineering can tell us, giving us estimates of what kind of cosmic structures are plausibly constructable by advanced civilizations, and what traces they would leave. Based on our current knowledge, it seems that it would be easy for such a civilization to rapidly occupy vast swathes of the universe in a visible fashion. There are game-theoretic reasons to suppose that they would do so. This leads to a worsening of the Fermi paradox, reducing the likelihood of "advanced but unseen" civilizations, even in other galaxies.

Sandberg's abstract:

The main finding is that intergalactic expansion is likely doable using local resources and a very high branching factor, and that makes the solar neighbourhood accessible to at least millions of times more potential alien civilizations. So either alien civilizations have to be even rarer than we think, they have to approach some non-visible behavioural attractor with very high fidelity, or they are here and hiding efficiently (in this case likely because the first expanding civilization used its probes to enforce some set of rules for everybody else).