And IMHO that's the main explanation for the Fermi paradox: we don't see aliens everywhere because they don't have a good reason to colonize other planets than their own either.
Travelling to another star would require a fully self-contained spaceship with energy, life support, food, medical facilities, even production facilities able to function for centuries or millenia. We simply don't know how to do that.
With a sustained nationwide effort comparable to WW2 we could most likely send a spaceship out if the solar system in ten years or so. But why would anyone do that?
Typical these things fall into one, two, many. Can you build one, two, many? These are very different propositions.
One means you know understand how to do it, mostly.
Two means you can repeat it, so you do understand it, it wasn't a fluke.
Many is scaling the process.
Its not 'if' question, just 'when'. You cant be space faring civilization and not know this.
Maybe they even live inside asteroids or ships orbiting a dwarf star, because they are mostly in a Matrix-like existence and don't have much of a physical life?
If someone provided a matrix world where you could live your dream life, I think a lot of us would choose to live in it. It would be so much better than real life. Our physical bodies could be maintained by robots, providing us with the perfect mix of sustenance and physical exercise to increase our life spans. Your body would eat healthy, but your mind would experience whatever food you would like.
Civilizations are made of individuals, who do not care about “race survival”. We know very well that global warming can wipe out most multicellular life out of our planet, and what do we do with this information?
That's insane to me that all theories about space colonization assume that alien societies would be rationally optimized towards the survival of the species when the only intelligent lifeform we know (us) behaves in the opposite fashion.
Nobody would chose to sacrifice themselves and their descendants (because that's what such an expedition is about), for mere curiosity. And nobody would fund an expedition that will not reach destination before multiple hundreds of years, even if the said expedition doesn't consume the entire industrial output of a major nation.
Space is BIG.
I bet if you had a one-way mission to Mars leaving in 12 months, you’d have a flood of applicants. Many hundreds minimum and probably several thousand.
Out of 8 billion people, assuming you had selection criteria that were even as strict as 1 in 1000 qualify, out of that 8 million, I think you’d easily be able to raise a crew.
This isn't interstellar travel, but I guess it'd work the if you consider it to be a one-way mission.
> Out of 8 billion people, assuming you had selection criteria that were even as strict as 1 in 1000 qualify, out of that 8 million, I think you’d easily be able to raise a crew.
Sure, it's always possible to hire enthusiastic youngsters for suicide missions, but after a year in captivity with no end in sight the suicide rate among the crew members would already be sky-high, if you haven't already faced a mutiny to try bringing the ship back to earth, that is.
That assumes reaching 5 light years in say 50 years
However once it's done a few times, then it can't be stopped. If you're going at say 1/1000th of the speed of light (50 years to travel, 450 years to settle and build the next wave is 1% the speed of light) then your successor species will have colonised the galaxy in 100 million years, and we know that hasn't happened.