For example this: can’t go faster than light, and because of that distances
are too huge argument do apply, but not in the way most people think IMO.
Just to have a little fun, who says they have to go faster than light?
Suppose some culture can get to 20% of light speed. What they do is hollow out an asteroid and use it for a space ship. Due to advanced biological sciences they have lifespans of 500 years and cold sleep technology that can slow their aging by 10 to 1. So that gives them an effective 5000 year travel time. At 20% of light speed they can cover 1000 light years.
So if they operate in shifts with 90% of the crew in cold sleep at any given time that would still be 900 light years and still does not take multigenerations into account.
So if an Interstellar civilisation sent out von Neumann probes and ships with live crews only went to interesting places then it is at least CONCEIVABLE that aliens could have found us hundreds or thousands of years ago and a ship with a live crew only showed up in the last few hundred years.
Sounds like a basis for a sci-fi story to me.
There could even be political factions among the crew. the PDs for Prime Directive versus the Uplifters who want to manipulate us, for our own good of course.
Almost anything can be imagined. Evidence is harder to come by.
OMG, old thread. Mentioned this in 2010.