Cosmological transition periods (Q580760)

A method is given for continuously following a model of a universe that in its evolution makes a transition from one type of universe to another. As an illustration, a universe is considered that initially is radiation- dominated and then makes a transition to a final matter-dominated Einstein-de Sitter universe. The epoch when the universe changes from being radiation-dominated to being matter-dominated is found and is related to the epoch when radiation decouples from matter.