Thank you! I'm glad I count on you to challenge my notions of reality and un-reality!

I don't know of you remember a later scene in the movie where someone defends that they had to dismiss Ellie's testimony because her on-board recorder only came back with static. And the other person in the room remarks "Yes, but it recorded 23 HOURS of static..." impossible for an event to took a few seconds to the visible eye.

The variable or "x-factor" in the idea of something being "verifiable" is inevitably TIME. Meaning, for example, that microwaves existed before we could detect and measure them. Simply because something is not visible, measurable or understandable isn't conclusive evidence that it doesn't exist, merely that we don't know... yet.