> 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.
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.