What are grammatical mistakes in my paragraph?

What are the grammer mistakes in my paragraph? We believe it true that a rare incident took place two billions years ago, a star was revolving in space blindly came near to the sun. As the sun and moon produce tides on the surface of the earth, in the same way that star would have produced tides on the surface of the sun but these tides would be quite different from those little tides which the small sized moon produces in our oceans. A stormy wave would have passed over the surface of the sun which , at last, gained the form of a huge mountain that can be hardly imagined. As the cause of the disturbance came closer and closer, this mountain became higher and higher.And before that ,the star began to recede(move) away , its force of gravity became so powerful that mountain of wave tore into pieces and it threw away small pieces in space. These small pieces have been revolving around the sun since that time. These are big and small planets, our earth is on of them.