Retrograde and prograde motion impact stage, the thickness of a protoplanetary disk is far larger than the size of planetary embryos so collisions are equally likely to come from any direction in three dimensions. This results in the axial tilt of accreted planets ranging from 0 to 180 degrees with any direction as likely as any other with both prograde and retrograde spins equally probable. Therefore, prograde spin with small axial tilt, common for the solar system's terrestrial planets except for Venus, is not common for terrestrial planets in general. The pattern of stars appears fixed in the sky, but that is only because
History of Solar System formation and evolution hypotheses itself. Most of the mass collected in the centre, forming the Sun; the rest of the mass flattened into a protoplanetary disc, out of which the planets and other bodies in the Solar System formed. There are, however, arguments against this hypothesis. French philosopher and mathematician René Descartes was the first to propose a model for the origin of the Solar System in his "Le Monde" (ou Traité de lumière) which he wrote in 1632 and 1633 and for which he delayed publication because of the Inquisition and it was published only after his death in 1664. In his view,