IR from waste heat should cold to warm black bodies radiating a lot of heat over a large area. It should have relatively few spectral lines. It might look a bit like a brown dwarf, but the output from a normal star is huge compared to a brown dwarf, so it should look like a really huge brown dwarf, which our normal models don’t offer a natural explanation for.
You see IR and all kinds of other emissions from all kinds of sources, what would distinguish artificial from natural?
IR from waste heat should cold to warm black bodies radiating a lot of heat over a large area. It should have relatively few spectral lines. It might look a bit like a brown dwarf, but the output from a normal star is huge compared to a brown dwarf, so it should look like a really huge brown dwarf, which our normal models don’t offer a natural explanation for.
Consider that maybe existing brown dwarfs and the laws apparently governing them are the artifacts of an alien intelligence.
Or maybe dark matter are the waste left after all useful energy has been extracted from the normal matter.
Or maybe our current models of supernova explosions fail because they don’t account for the alien intelligences using them for their purposes.
How do you tell natural from artificial? What would be a generic artifact of any powerful optimizer?