  Earth and Moon are shown here to be composed of oxygen isotope reservoirs
that are indistinguishable, with a difference in {\Delta}"17O of -1 +/- 5ppm
(2se). Based on these data and our new planet formation simulations that
include a realistic model for 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 {\Delta}"17O within approximately 1 per mil of the terrestrial
value, suggesting that these impactors were water rich.
