Is Humanity Ready for First Contact?

[Anomalocaris]

As for colonizing other galaxies, nuclear impulse propulsion is too slow.  I'm not saying if we did fill up this galaxy we wouldn't want to do another, it's just that the technology to fill up a galaxy 100,000 lightyears across with handy places to stop and relax, refresh and refuel along the way isn't going to work very well on a nonstop flight of 2 million lightyears.

In the galaxy scenario, if flight times were limited to 1000 years, the task could still be accomplished as a multi-generation vessel at 0.10C would have a range of ~100 light years.  At 0,10C, getting to the Andromeda galaxy is going to take 20 million years.  That isn't feasible. Even building a single vessel for the 1000 year flight is quite a task.  Dyson thought building the first one might take 400 years.  I think subsequent vehicles would be built much faster.  And realize, if every established colony built another vessel relatively quickly after becoming established, and also refurbed their own vessel, then you get into an exponentiation of how quickly the entire galaxy can be explored.  

Don't think so much how fast an individual ship can travel in a straight line.  Instead consider how fast the volume of explored galactic space can increase if the number of even relatively slow ships doing the exploring doubles every 500 - 1000 years.

I'm just looking at how a Darwinianaly inspired, technologically capable society can fill up a galaxy.  It turns out it isn't insuperably difficult with technology humans developed 50 years ago.

And as for ETs that aren't Darwinianaly inspired, I guess I don't know what that would entail.  I think Darwin and his ideas describe all successful lifeforms in the universe.  Survival of the fittest is the defining trait of that which survives.

That it looks like humans are backsliding a bit (go watch the movie Idiocracy) doesn't mean the rest of our (possible) contenders are doing the same.

And a reminder, in all our galaxy, it just takes one civilization with what is now 50 year old earth technology and the will to employ it, to colonize our galaxy.

How long a trip an alien race would continence is an unknown.  We may well be too antropocentric in assuming a 20 million year trip would be a deal breaker under the conditions of alien life span, alien social and economic imperative, alien psychology, and alien technology and raw material.

We also may be too beholden to the limitation imposed by our own technology and organization in assuming exploration necessarily involve primarily a series of point a - point b transitions involving a physical spaceship.

It is sound to assume that what we can reasonably postulate is what seems plausible to us at the current time.  It is unsound to assume what we can reasonably postulate represent all that we should assume can be postulated.