Irene Klotz, for ABC Science:

Using advanced computer modelling, Mastrobuono-Battisti and colleagues ran dozens of simulations of later-stage planet formation, each time starting with 85 to 90 planetary embryos and 1,000 to 2,000 planetesimals extending from about halfway between the orbits of Mercury and Venus to within 50 million miles or so of Jupiter’s orbit.

Within 100 million to 200 million years, each simulation typically produced three to four rocky planets as a result of colliding embryos and planetesimals, the scientists found. Looking particularly at the last moon-forming impact scenarios, the scientists assessed the likelihood that Theia and Earth had the same chemical composition.

Do the Earth and Moon still carry genetic material of Theia? According to more and more accurate simulations, it’s quite possible. Interesting to ponder how things might have been different otherwise. (Also, I love the idea of planetary embryos and “planetesimals.”)