It wasnt a big bang. Its a slow and gradual expansion of the universe and its happening as we speak. Its so slow we dont notice it day to day.
The earth is growing in tandem with the universe. There was never a Pangea. It would not make sense to have all the landmass on one side due to the center of gravity shifting in that case and it does not make sense to just have landmass float around either.
Instead the earth was much smaller with practically no oceans, and all the landmass was able to cover the globe.
As the earth is growing the landmass is stretched thinner and thinner.
Eventually the earth may become a gas giant or something. Maybe even a sun. Who knows.