ABSTRACT When Warren Hamilton passed away in October 2018, he left behind the manuscript for a synthesis paper that was published in Earth-Science Reviews in 2019: “Toward a myth-free geodynamic history of Earth and its neighbors.” Integrating hundreds of detailed studies across four worlds and billions of years, the paper’s outlook is heterodox, presenting alternatives to conventional wisdom in every paragraph for almost 50 pages. During the last years of his life, Hamilton had worked steadily on this paper, which he viewed as the culmination of his long career. This chapter tells the story of how Hamilton wrote his last paper, summarizes a few of the many ideas it contains, and describes how, with help from his colleagues, the paper was posthumously completed and published.

ABSTRACT Lateral accelerations require lateral forces. We propose that force imbalances in the unique Earth-Moon-Sun system cause large-scale, cooperative tectonic motions. The solar gravitational pull on the Moon, being 2.2× terrestrial pull, causes lunar drift, orbital elongation, and an ~1000 km radial monthly excursion of the Earth-Moon barycenter inside Earth’s mantle. Earth’s spin superimposes an approximately longitudinal 24 h circuit of the barycenter. Because the oscillating barycenter lies 3500–5500 km from the geocenter, Earth’s tangential orbital acceleration and solar pull are imbalanced. Near-surface motions are enabled by a weak low-velocity zone underlying the cold, brittle lithosphere: The thermal states of both layers result from leakage of Earth’s internal radiogenic heat to space. Concomitantly, stress induced by spin cracks the lithosphere in a classic X-pattern, creating mid-ocean ridges and plate segments. The inertial response of our high-spin planet with its low-velocity zone is ~10 cm yr –1 westward drift of the entire lithosphere, which largely dictates plate motions. The thermal profile causes sinking plates to thin and disappear by depths of ~200–660 km, depending on angle and speed. Cyclical stresses are effective agents of failure, thereby adding asymmetry to plate motions. A comparison of rocky planets shows that the presence and longevity of volcanism and tectonism depend on the particular combination of moon size, moon orbital orientation, proximity to the Sun, and rates of body spin and cooling. Earth is the only rocky planet with all the factors needed for plate tectonics.

ABSTRACT Most differences in the gross surface morphologies, tectonic styles, overall geologic histories, and atmospheres of the rocky bodies in the solar system can be explained by contributions and dissipation of gravitational and radiogenic energy over geologic time. These two energy sources are large and measurable and can be extrapolated back in time. Accretion was likely cold, and directly converted gravitational potential energy into axial spin, a prominent feature of planets that is otherwise unexplained. Impact heating was mostly limited to planetary surfaces in the final stages of accretion. Frictional dissipation of spin contributed sufficient energy to ignite the primordial Sun and heated Earth and Venus by nearly as much as has the radioactive decay of K, U, and Th over geologic time. Energy inputs have been continuously offset by loss of heat to the surroundings. The magnitudes of most important energy contributions depend on the planet radius R and also on the distance r to the Sun. Quantitative, albeit approximate, relationships show that the net specific energy (kJ/kg) contributed to the rocky bodies over geologic time goes as: Earth ~ Venus >> Mars ~ Mercury ~ Moon >> asteroids. Net energy inputs increased the average internal temperatures of Earth and Venus by ~3000 K but heated asteroids by only a few hundred kelvins.

ABSTRACT The age of the Moon (1.55–1.78 b.y. old) as calculated from its regression as a function of geological time is much younger than the currently accepted age (ca. 4.52 Ga) determined by radiometric dating of lunar samples collected by Apollo astronauts. This discrepancy has posed a serious challenge for planetary scientists to account satisfactorily for the formation and subsequent breakup of Pangea. Conventional orbital models of the Earth-Moon system cannot explain why Pangea formed on only one hemisphere of Earth, whereas this study’s proposed two-stage rotation model can provide a plausible explanation. Calculations and a plot of the Earth-Moon separation distance against geologic age suggest that, during their first ~3.0 b.y., Earth and the Moon were mutually tidally locked, rotating as an integrated unit about a barycenter (designated as stage I rotation). Beginning 1.55 Ga, however, Earth disengaged from its tidal lock with the Moon and entered its current orbital mode (designated as stage II rotation). The dynamics associated with the two rotational modes of the Earth-Moon system throughout Earth’s history are hypothesized to constitute the driving forces for the migration and coalescence of landmasses during stage I rotation to create Pangea, and its ultimate breakup and drifting during stage II rotation.

ABSTRACT Suborbital analysis (SA) is presented here as the study of ballistics around a spherical planet. SA is the subset of orbital mechanics where the elliptic trajectory intersects Earth’s surface at launch point A and fall point B , known as the A -to- B suborbital problem, both launch and fall points being vector variables. Spreadsheet tools are offered for solution to this problem, based on the preferred simplified two-body model. Although simplistic in top-level description, this problem places essential reliance on reference frame transformations. Launch conditions in the local frame of point A and rotating with Earth require conversion to the nonrotating frame for correct trajectory definition, with the reverse process required for complete solution. This application of dynamics requires diligent accounting to avoid invalid results. Historic examples are provided that lack the requisite treatment, with the appropriate set of solution equations also included. Complementary spreadsheet tools SASolver and Helix solve the A -to- B problem for loft duration from minimum through 26 h. All provided spreadsheet workbook files contain the novel three-dimensional latitude and longitude plotter GlobePlot. A global ejecta pattern data set calculated using SASolver is presented. As visualized through GlobePlot, SASolver and Helix provide solutions to different forms of the A -to- B problem, in an effort to avoid errors similar to the historic misstep examples offered as a supplement. Operating guidelines and limitations of the tools are presented along with diagrams from each step. The goal is to enable mechanically valid interdisciplinary terrestrial ejecta research through novel perspective and quality graphical tools, so others may succeed where 1960s National Aeronautics and Space Administration researchers did not.