Depends on the scientist sentient barnacle's frame of reference; I'm sure it could posit naturalistic explanations for weather changes and distant things that move across the horizon and flash light at us. I'm not saying it's impossible for us to observe the activity of extraterrestrial lifeforms (that would be absurd), simply that traces of intergalactic activity might not be immediately obvious; surely one of the side-effects of a Dyson sphere, for instance, would be to render the star almost undetectable to our telescopes.
surely one of the side-effects of a Dyson sphere, for instance, would be to render the star almost undetectable to our telescopes.
No. A Dyson sphere would just emit a lot less radiation in the region that we happen to perceive as "visible". This is a special case of "Stealth is (close to) impossible in Space"
