Pangaea and the arrival of the Oceans
The diameter of the Sun is about 1,392,000 km. In order to get a hot Sun the only thing we require is for a planet to become a certain size. In order to get a Sun made from Hydrogen we must strip away all neutrons.
We are then left with single protons and electrons. The Milky Way is 13,500 million years old. Mass of a Black Hole is 1,000 times less than the mass of the galaxy The Milky Way.
However a Black Hole is 4 million times the mass of our Sun.
The most promising place to look for Black Holes is in binary systems such as HDE 226868-CygnusX-1 There is an apparent observation of gravitational waves emanating from the centre of our own galaxy. This energy would be equivalent to a loss mass of many thousands of solar masses per year.
This is in gross conflict with other observations.