Life would be impossible on such a planet. It wouldn't get enough heat and light, and if it rotated there would be total darkness half of every day. There wouldn't be any native inhabitants. You couldn't expect life—which is fundamentally dependent on light—to develop under such extreme conditions of light deprivation. Half of every axial rotation spent in Darkness! No, nothing could exist under conditions like that.

Nightfall: and other stories (ed. Doubleday Books, 1969)