Given our massive uncertainty about the endurance/motives/etc. of super-advanced starfaring civiliations, I don't think it's justified to say that alien interlopers are "vanishingly unlikely".
This statement comes up all the time as if it automatically wins any discussion of alien civilizations. It contains a number of huge possibly specious assumptions. The first and most obvious is that even a long-lived civilization could construct a technology allowing a non-trivial amount of mass to accelerate to 0.1c and more importantly decelerate at the destination to a relative velocity of zero to facilitate the colonization.
A species beginning colonization on one end of the galaxy might not be the same species at all by the time it reached the other end of the galaxy a million years later. There might be a whole spectrum of new species that emerged along the way.
We haven’t been back to the moon. Maybe some much more advanced civilization would do one star shot, found one colony, and be like awesome now we are in two solar systems and that’s enough.
A solar system is huge. It’s probably a lot easier to terraform terrestrial planets or build a living Dyson swarm of Stanford toruses than build a starship. Certainly easier than building more than one starship. The human race could probably expand for hundreds of thousands of years in this solar system before we would ever feel any actual pressure to go elsewhere.
There are over 100 billion stars in the Milky Way alone. Your statement might be true for 99% of civs, yet the remaining 1% are still gigacolonizers.
>It’s probably a lot easier to terraform terrestrial planets or build a living Dyson swarm of Stanford toruses than build a starship. Certainly easier than building more than one starship. The human race could probably expand for hundreds of thousands of years in this solar system before we would ever feel any actual pressure to go elsewhere.
If you're Kardashev type 2, what are you going to do with all of that energy anyways? Why not give your Stanford toruses sublight engines, and turn them into superfast interstellar cruise ships full of amenities? Lawnchair Larry said it well: "A man can't just sit around."
Is there any reason to believe this should be impossible, in principle?
Note my use of the word "impossible", as opposed to "extremely difficult". The colonization timeline is still the same order of magnitude if it takes 100,000 years of research and engineering to crack the problem. Think about what humanity has achieved in the past 50 years, then multiply by 2000.
It can equally be possible, impossible or not worth it.
Interstellar rocks crashing at you with velocity of 0.1c might hurt a lot.
I would not like my government spending 99% of everybodies income for 100 generations, just to send one human to proxima centauri.
Growth and efficiency gains are not guaranteed, and will eventually stop. (If you take the mass of universe, put it into mc^2, and assume 5% energy consumption increase per year you get 2k years to consume whole universe worth of energy)
We can’t just assume that humans will reach Proxima Centauri.
Also your timeline presumes self replicating spaceships exist or could exist. Have you ever thought about what kind of spaceship could mine metals, smelt them, make glass, build a chip fab etc?
The sort of technological capabilities we have today would sound laughable to people a mere thousand years ago. Who knows what will be doable in a few million years, which is a blink in the grand scheme of the cosmos.
We can’t say it’s likely or unlikely.
https://www.researchgate.net/publication/394040040_Aligned_m...
the crazy thing is that you are so biased against these researchers that you have even shut out the possibility that these (and the DC UFOs) are extremely high formation flying USAF vehicles (for example).
