Monday, June 25, 2018

Has Fermi's Paradox been solved?

A paper for the Royal Society argues that the level of uncertainty about many of the assumptions we have made when trying to calculate the "Drake Equation" and work out how many other planets we would expect to develop intelligent life.

Previous attempts to do this have suggested that there are so many, many stars in the galaxy that even if the probability of a star developing one or more intelligent civilisations is very low, there should still be a fair number of them about, leading to the Fermi Paradox.

We have (perhaps very unwisely) made it likely that any high-energy civilisation within about seventy light-years knows that there is an emerging level one civilisation in the Sol system. If there was a civilisation at a remotely similar tech level to ours at Sirius or any of the other nearby stars the SETI programme would have found them. The Fermi Paradox is that we should have observed evidence of other emerging civilisations, and we haven't.

Hence the "Great Filter" - what stops most stars developing a civilisation which would change it's environment in ways we could observe - and are we past it, or yet to hit it?

The great filter could be anything from the benign - suppose for example that all civilisations wise enough to survive long learn to respect their environment, which might include not doing things like wasting vast amounts of energy beaming powerful signals around the universe or enclosing your star even if you could - to the things we might do to ourselves, e.g. most civilisations might blow themselves up in a nuclear war - to external threats - there might be a psychotic supercivilisation which obliterates any potential rivals, in which case we're probably done for.

The new paper argues that previous attempts to build Drake-like equations implicitly assumed certainty regarding highly uncertain parameters. The authors examined these parameters, incorporating models of chemical and genetic transitions on paths to the origin of life, and provide evidence that given extant scientific knowledge there are in fact uncertainties about these assumptions which span multiple orders of magnitude. When the model is recast to represent what the authors think are more realistic distributions of uncertainty, they find a substantial possibility of there being no other intelligent life in the part of the universe we can observe. If they are right that appears to resolve the Fermi Paradox.

The paper is called "Dissolving the Fermi Paradox" by Anders Sandberg, Eric Drexler, and Toby Ord and you can find a listing on the Cornell University site for it here.

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