[user104658]

Originally Posted by James

Fermi paradox questions why we have no evidence of alien intelligence given the universe is billions of years old, and it would only take a fraction of that time for a sufficiently advanced civilisation to traverse, say, the Milky Way galaxy. Maybe we are the only instance in the universe of life or intelligence starting? We can't rule that out.

That's why I think FTL (faster than light) travel may well be entirely impossible at any level of technological capability. I think we more or less CAN rule out being the only instance of intelligent life. The universe is unimaginable in scale and, as you say, billions of years old. We know that life is possible, because we exist. Apply that possibility to near-infinity and the chances that it has only happened once are improbable to the point of impossibility.

And yet, as you say, zero evidence of other intelligent alien life... but that stops being a paradox if you take the bold part out of the equation. True that even at the fastest sub-light speeds you could cross the galaxy in a fraction of that time... but would it ever be feasible or desirable? Would any being intelligent enough to develop the technology to travel through space for generations, taking YEARS to even get from one star to the next, actually bother to do so? IMO the absence of "warp" or "wormhole" travel makes the exploration of anything but the "nearest" star systems impractical. It probably simply can't be done.