Part 7/11:
The notion of the integrated Sachs-Wolfe (ISW) effect posits that as photons from the CMB journey through cosmic voids, they experience energy alterations due to shifts in density across the void's landscape. As the universe expands, these voids grow larger, potentially leading photons to lose more energy than they gain when exiting. Under this premise, the cold spot may not be a primary feature of the early universe but rather an artifact created by our view through a substantial void.