Solar system acquired current configuration not long after its formation
(PHYSorg.com Space & Earth)

The hypothesis that the solar system originated from a gigantic cloud of gas and dust was first floated in the second half of the 18th century by German philosopher Immanuel Kant and further developed by French mathematician Pierre-Simon de Laplace. It is now a consensus among astronomers. Thanks to the enormous amount of observational data, theoretical input and computational resources now available, it has been continually refined, but this is not a linear process.