Or 7 (is it now?), based on a thread above, organic civilizations become machine civilizations, which can colonize much more efficiently because long journey ti

Or 7 (is it now?), based on a thread above, organic civilizations become machine civilizations, which can colonize much more efficiently because long journey times don't bother them, and more stealthily because they can make do with comets and moons and such that won't support organic life.