The dispensation of conscience, the time immediately after the fall of man when Adam and Eve were banished from the garden of Eden, we've also deduced was the first purification of heaven.
The history of creation is the working out of the process of purification. Eventually there will be absolute purity in heaven, and there will be only corruption left on Earth. At this time the Earth will be disposed of.
The creation of gravity caused the majority of the darkness and corruption in the universe to accumulate at the center of creation. This became the body of the Earth. The majority of light and purity accumulated in heaven.
If no man has ascended up to heaven, except Jesus Christ who came down from heaven, then we have a few questions to ask...