[James]

Originally Posted by Toy Soldier

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.

One of the reasons I have some doubts (now) about intelligent life existing elsewhere in the universe is that on Earth simple single-cell life started quite quickly, after conditions became right, but it took about 2 billion years for eukaryotic cells to come about which led to complex living organisms, and scientists think that this only happened because of a single chance encounter.

There's this Brian Cox video where he explains it - http://www.bbc.co.uk/programmes/p029n23h