In general they say what created the universe, was it a Big Bang ? Or something else ? Before the Big Bang existed in hindsight the universe has to exists before the Big Bang evolved. Thus the universe was already there, but the fundamental truth, what started it was it a combination of solar sytems.simulantiousely creating other solar Systems expanding the universe, there was no big bang, only a collision of a gigantic comet that has rock,ice and water that was enough to create planets in the solar system, and to produce life.
when the comet crashed into the sun, the debris of rock ,water, ice, and trace elements, started a process of accretion that helped built the planets in the solar system.this explains why comets in general have an elliptical orbit.around the sun.most ancient comets still do today, my guess that halleys comet could have helped created our solar Sytem.Before a comet arrived, there was only a sun and dark matter which came to be traversed and changed into electro magnetic waves after the collision, which helped all the planets keep in orbit around the sun.