"Eliezer S. Yudkowsky" <email@example.com> writes:
> What we should be looking for is byproducts - for example, a
> sphere-shaped region inside a galaxy that contains no stars of a certain
> type. Our telescopes aren't up to that, I think, but you get the idea.
> Does anyone have any ideas about what kind of involuntary signatures
> might be left by alien civilizations?
Dyson was likely first with his suggestion of looking for Dyson spheres.
We really need a better understanding of the limits of computation before we can say for certain what to look for. The above sphere is an anomaly that would be detectable even without this understanding; if we think that intelligence is only emerging right now, so we can see natural and colonised regions, then we can look for anomalies. If intelligence has been around for some time, then it is hard to tell what is natural (do stars really form naturally? :-)
Anders Sandberg Towards Ascension! firstname.lastname@example.org http://www.nada.kth.se/~asa/GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y