The Delphic Expanse was an area of space approximately 50 light years from Earth in the Alpha Quadrant. While its exact dimensions were unknown, Vulcan scientists estimated the Expanse to have been about 2,000 light years across in the 22nd century. At that time, it was also surrounded by thermobaric clouds that made it difficult to enter and exit the region. It was generally avoided by Vulcan ships because of various spatial anomalies existing inside; in some parts of the Expanse the known laws of physics did not seem to apply.