"The Stars, Like Dust" states explicitly that the Earth is radioactive because of a nuclear war. Asimov later explained that the in-universe reason for this perception was that it was formulated by Earthmen many centuries after the event, and which had become distorted, due to the loss of much of their planetary history. This work is generally regarded as part of the "Empire" series, but does not directly mention either Trantor or the Spacer worlds. One character is seen with a visi-sonor, the same musical instrument that is played by the clown Magnifico in "Foundation and Empire". Based on details from the novel, such as Earth still being mostly habitable and the absence of a unified galactic government, it probably would fall during the early formation of the Empire (before it expanded to encompass the galaxy).