[sten]

even at a single light year away, what the hell would they expect to find?

unless they’re making MASSIVE ships, you won’t see them

a dyson sphere? ring world?

just seems over the top for what would be needed.

of course, maybe the evidence of their existence ... is us

[CardCarryingMember.VastRightWC]

Or a more pessimistic possibility:

• Radio waves only exist for a microscopically tiny window of time, because...
• Not many years after civilizations learn to use radio waves, they develop nuclear bombs, with the potential to wipe out all life on their planet (cockroaches excepted).
• Not long after they *think* they have the nuclear proliferation monster under control, they develop the internet.
• The internet's overall effect is to drive people apart, hating each other, going psycho.
• The combination of hundreds of millions of nut cases plus the nukes, obliterates the civilization and stops all the radio waves, about a century after they first started.