A solar or lunar eclipse can darken the sun and the moon, yet here the author’s mention also of the stars suggests we are not to think of an eclipse. Heavy cloud coverage can hide the sun, the moon, and/or the stars so that much of their light is darkened. The gloominess that comes with excessive cloud coverage hinders human thriving, leading to depression and feelings of melancholy. Volcanic eruptions can also put so much ash in the air that crops cannot thrive due to a shortage of light and heat, leading to hunger.
12 The fourth angel blew his trumpet, and a third of the sun was struck, and a third of the moon, and a third of the stars, so that a third of their light might be darkened, and a third of the day might be kept from shining, and likewise a third of the night.