> "The intense IR radiation would have originated from the entire sky. Darkness would have been eliminated worldwide for several hours and shadows curtailed. Sh

> "The intense IR radiation would have originated from the entire sky. Darkness would have been eliminated worldwide for several hours and shadows curtailed. Shadowing effects would have been restricted to a direct proportion of the fraction of the sky blocked by a massive object. An organism at the foot of a lengthy vertical cliff, for example, would have been spared radiation from just under half the sky. It would not have been sufficient to shelter in a gully, under an isolated tree, or even under a sparsely forested canopy. Life confined to Earth’s surface would have perished well before incineration."