Edward D. Young, Issaku E. Kohl, Paul H. Warren, David C. Rubie, Seth A. Jacobson, and Alessandro Morbidelli
Science 29 Jan 2016:
Vol. 351, Issue 6272, pp. 493-496
Earth and the Moon are shown here to have indistinguishable oxygen isotope ratios, with a difference in Δ′17O of −1 ± 5 parts per million (2 standard error). On the basis of these data and our new planet formation simulations that include a realistic model for primordial oxygen isotopic reservoirs, our results favor vigorous mixing during the giant impact and therefore a high-energy, high-angular-momentum impact. The results indicate that the late veneer impactors had an average Δ′17O within approximately 1 per mil of the terrestrial value, limiting possible sources for this late addition of mass to the Earth-Moon system.