> Colonizing the Milky Way only takes 1 million years if you can travel 10% of the speed of light.

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.

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asdff 8 days ago | parent | next [-]

Also a lot of assumptions about mutation rate. Anatomically modern humans appeared 300k years ago. Behaviorally modern humans appeared 50k years ago.

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.

	▲	0xDEAFBEAD 8 days ago \| parent \| next [-]
		It seems to me that such speciation supports the assumption of endurance. Over time you'd see selection for species which are patient, diligent, fecund star colonizers. Just like medieval Europeans spent decades or centuries building a cathedral, over time you'd select for species which spend centuries working on their next starshot.
	▲	grumbelbart2 8 days ago \| parent \| prev [-]
		I'd expect the first exploration to be done by machines, and digital transfer of the controlling instance would remove almost all drift.

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0xDEAFBEAD 8 days ago | parent | prev | next [-]

>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.

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.

	▲	earnestinger 8 days ago \| parent [-]
		It’s unknown. 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.

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api 8 days ago | parent | prev [-]

And then do that gargantuan feat more than once, with every colony growing exponentially until it can do it again.

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.

	▲	0xDEAFBEAD 8 days ago \| parent [-]
		>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. 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."