I am interested in the minimum size of a rocky planetoid needed to "crush" it into spherical shape. I'm also interested in its initial temperature because liquid or plastic masses obviously need much less crushing. The Wikipedia article "Giant Impact Hypothesis" says, In 2007, researchers from the California Institute of Technology showed that the likelihood of Theia having an identical isotopic signature as the Earth was very small (less than 1 percent). They proposed that in the aftermath of the giant impact, while the Earth and the proto-lunar disk were molten and vaporized, the two reservoirs were connected by a common silicate vapour atmosphere, and that the Earth–Moon system became homogenized by convective stirring while the system existed in the form of a continuous fluid. Such an "equilibration" between the post-impact Earth and the proto-lunar disk is the only scenario capable of explaining the isotopic similarities of the Apollo rocks with rocks from the Earth's interior. For this scenario to be viable, however, the proto-lunar disk must exist for a time period of about 100 years. That makes me wonder about the ambient temperature around Earth orbit at that time and the rate of cooling of the initial Lunar ejecta. Ejecta staying molten for 100 years sounds like a long time in cold cold space. Are there articles for laymen about solid spherical vs non-spherical vs rubble pile planetoid formation?