Are we not on an ark like this NOW?
“Are we not on an ark like this NOW?”
No, we are not. The Earth and like planetary bodies are too large to serve as interstellar transports. The asteroids to be used as the arks would require certain types of characteristics that cannot be accomplished with planetary bodies the size of the major terrestrial planets of this Solar System. They would have a mass small enough to be accelerated and decelerated with relatively practical methods of propulsion such as electric ion engines, solar sails, and so forth. They would have a mass large enough to provide the capacity to house an integrated economy for a substantial human community and self-sufficient economy inside the asteroid. They would need have a primarily nickel-iron composition with the strength to retain structural integrity despite internal mining, rotation for centrifugal simulated gravity, and accelerating forces for the voyages. These asteroidal transport craft would typically travel in convoy with other such craft to provide mutual support, and with smaller asteroidal service craft too small for a self-sufficient colony. The asteroidal transports would likely serve as permanent homes for most of their population, while some of the population would be expected to colonize other new asteroids and planetary bodies discovered on their journeys.