Popular books discussing the concept of emptiness include "The Book of Nothing" by John Barrow, "The Nothing That Is" by Robert Kaplan, and "Zero: The Biography of a Dangerous Idea" by Charles Seife. Brian Greene's "The Fabric of the Cosmos" explores the philosophy and science of empty space, particularly Newton's spinning bucket, providing insights into the perception of time and movement. However, it does not address the speed of spacetime in a truly empty universe. The discussion also touches on the accuracy of atomic clocks, particularly cesium atoms, and their relation to movement in space. Overall, while there are several accessible texts on the topic, specific inquiries about time in an absolute void remain less explored.