This was actually covered in a book I read (I think it was The World Without Us). Summary: even our reactors leave clear traces that will be detectable about as long as the mass extinction event we’re causing. So a civilization and species-killing thermonuclear war would definitely be detectable by us.
This was actually covered in a book I read (I think it was The World Without Us). Summary: even our reactors leave clear traces that will be detectable about as long as the mass extinction event we’re causing. So a civilization and species-killing thermonuclear war would definitely be detectable by us.