From the Earth to the Moon: Resolving estimates of proto-Earth accretion with lunar-forming impact
(PhysOrg.com) -- One of the more challenging fields of scientific inquiry is planetary formation and most relevant is that of our own Earth and Moon. The current view, based on chronometry (scientific time measurement) of terrestrial rocks, is that (1) Earth formed via accretion some 30 million years after our solar system, and (2) the so-called Moon-forming Giant Impact (MGI) occurred immediately (in geological time) afterwards. However, simulations and lunar rock examination appear to possibly place MGI as much as 70 million years later. Recently, scientists in the Department of Earth and Planetary Sciences at Harvard University have proposed a model that explains this discrepancy using chronological isotopic analysis and formation partitioning of siderophile, or iron-living, elements. The researchers conclude that a late formation of the Moon is possible but requires very fast formation of the Earth prior to the late Moon-forming impact.