The earliest material found in the Solar System is dated to 4.5672±0.0006 bya;[167] therefore, it is inferred that the Earth must have been formed by accretion around this time. By 4.54±0.04 bya[24] the primordial Earth had formed. The formation and evolution of the Solar System bodies occurred in tandem with the Sun. In theory a solar nebula partitions a volume out of a molecular cloud by gravitational collapse, which begins to spin and flatten into a circumstellar disk, and then the planets grow out of that in tandem with the star. A nebula contains gas, ice grains and dust (including primordial nuclides). In nebular theory planetesimals commence forming as particulate accrues by cohesive clumping and then by gravity. The assembly of the primordial Earth proceeded for 10–20 myr.[168] The Moon formed shortly thereafter, about 4.53 bya.[169]