Related Experiment Video
Updated: Jul 16, 2026

Laboratory Drop Towers for the Experimental Simulation of Dust-aggregate Collisions in the Early Solar System
Published on: June 5, 2014
Oxygen isotopes and the moon-forming giant impact
U Wiechert1, A N Halliday, D C Lee
1Institute for Isotope Geology and Mineral Resources, Department of Earth Sciences, ETH Zentrum, Sonneggstrasse 5, 8092 Zürich, Switzerland. wiechert@erdw.ethz.ch
Abstract:
We have determined the abundances of 16O, 17O, and 18O in 31 lunar samples from Apollo missions 11, 12, 15, 16, and 17 using a high-precision laser fluorination technique. All oxygen isotope compositions plot within +/-0.016 per mil (2 standard deviations) on a single mass-dependent fractionation line that is identical to the terrestrial fractionation line within uncertainties. This observation is consistent with the Giant Impact model, provided that the proto-Earth and the smaller impactor planet (named Theia) formed from an identical mix of components. The similarity between the proto-Earth and Theia is consistent with formation at about the same heliocentric distance. The three oxygen isotopes (delta17O) provide no evidence that isotopic heterogeneity on the Moon was created by lunar impacts.
Related Concept Videos
Conditions on Early Earth
Conditions on Early Earth
Impulse
Additionally, it can be shown that the total...
Gravity between Spherical Bodies
This assumption can be proved easily by showing that the expression for gravitational potential energy between a hollow sphere of mass (M) and a point mass (m) is the same as it would be for a pair of extended...
Gravitation
Impact: Problem Solving
By designating the launch point as the origin and utilizing kinematic equations, the vertical component of the projectile's velocity at the point of impact is...

