What was the raisin bun theory And why was it called this?

The raisin bun theory is a model of the universe's structure that suggests galaxies are like raisins embedded in a rising dough, representing space itself. As the dough expands, the raisins move away from each other, illustrating how galaxies are receding as the universe expands. It is called the "raisin bun theory" because the analogy of a bun filled with raisins effectively visualizes the distribution of galaxies in an expanding universe. This model helps to explain the observed redshift of distant galaxies as evidence of cosmic expansion.