* All intelligent life goes extinct before achieving interstellar colonization, or is content to remain in their home stellar system.
* We are in the first generation of life in the galaxy capable of achieving interstellar colonization, due to the time scales required for sufficient heavy elements and evolutionary complexity to arrive.
* All intelligent life goes extinct before achieving interstellar colonization, or is content to remain in their home stellar system.
* We are in the first generation of life in the galaxy capable of achieving interstellar colonization, due to the time scales required for sufficient heavy elements and evolutionary complexity to arrive.