|Nightfall 1990 edition|
Total darkness is unknown, and as a result so are stars outside the 6-star system. Their scientists predict that once every 2049 years a brief “night” will occur. Since the current population has never experienced universal darkness, the scientists conclude that the darkness itself would traumatize the people, and that the inhabitants of the planet must prepare accordingly.
But when night falls the scientists themselves get a surprise. Together with the rest of the population they are presented with the spectacle of a black sky filled with hitherto-invisible stars. The short story does not dramatize subsequent events, but in 1990 Asimov (with Robert Silverberg) adapted it into a novel, in which civil disorder breaks out, cities are destroyed in massive fires, competing groups try to seize control, and civilization collapses.
I've taken this from the plot summary in Wikipedia. I must get hold of this story.