Concept: Giant Impact Theory
A Perspective piece in Science on the Giant Impact Theory, as an introduction to two new papers with different simulation solutions. Paper gives background, explains two papers, competing theories, and future challenge to this question.
Any simulation needs to explain: [1] the Moon’s angular momentum, and [2] slightly lower density; [3] it’s apparent age given tungsten isotopes (30my after the start of the solar system); [4] the presence of old rocks that should originate in a magma ocean despite that being a time when heat-producing nuclides should be extinct; [5] the virtually identical oxygen isotope compositions of the Moon and Earth, [6] and similarly for refractory isotope compositions (esp. silicon, tungsten, titanium).
