Simon J. Lock's research while affiliated with University of Bristol and other places

Publications (22)

Article
Full-text available
Tides and Earth-Moon system evolution are coupled over geological time. Tidal energy dissipation on Earth slows Earth's rotation rate, increases obliquity, lunar orbit semi-major axis and eccentricity, and decreases lunar inclination. Tidal and core-mantle boundary dissipation within the Moon decrease inclination, eccentricity and semi-major axis....
Article
Full-text available
A giant-impact origin for the Moon is generally accepted, but many aspects of lunar formation remain poorly understood and debated. Ćuk et al. proposed that an impact that left the Earth–Moon system with high obliquity and angular momentum could explain the Moon's orbital inclination and isotopic similarity to Earth. In this scenario, instability d...
Preprint
Full-text available
A giant impact origin for the Moon is generally accepted, but many aspects of lunar formation remain poorly understood and debated. \'Cuk et al. (2016) proposed that an impact that left the Earth-Moon system with high obliquity and angular momentum could explain the Moon's orbital inclination and isotopic similarity to Earth. In this scenario, inst...
Preprint
Full-text available
The Earth-Moon system is unusual in several respects. The Moon is roughly 1/4 the radius of the Earth - a larger satellite-to-planet size ratio than all known satellites other than Pluto's Charon. The Moon has a tiny core, perhaps with only ~1% of its mass, in contrast to Earth whose core contains nearly 30% of its mass. The Earth-Moon system has a...
Conference Paper
We discuss major challenges in modeling giant impacts between planetary bodies, focusing on the equations of state (EOS). During the giant impact stage of planet formation, rocky planets are melted and partially vaporized. However, most EOS models fail to reproduce experimental constraints on the thermodynamic properties of the major minerals over...
Article
Scientific visualization tools are currently not optimized to create cinematic, production-quality representations of numerical data for the purpose of science communication. In our pipeline Estra, we outline a step-by-step process from a raw simulation into a finished render as a way to teach non-experts in the field of visualization how to achiev...
Article
Full-text available
The Moon forming giant impact marks the end of the main stage of Earth’s accretion and sets the stage for the subsequent evolution of our planet. The giant impact theory has been the accepted model of lunar origin for 40 years, but the parameters of the impact and the mechanisms that led to the formation of the Moon are still hotly debated. Here we...
Preprint
Pressure is a key parameter in the physics and chemistry of planet formation and evolution. Previous studies have erroneously assumed that internal pressures monotonically increase with the mass of a body. Using smoothed particle hydrodynamics and potential field method calculations, we demonstrate that the hot, rapidly-rotating bodies produced by...
Preprint
Full-text available
Scientific visualization tools are currently not optimized to create cinematic, production-quality representations of numerical data for the purpose of science communication. In our pipeline \texttt{Estra}, we outline a step-by-step process from a raw simulation into a finished render as a way to teach non-experts in the field of visualization how...
Article
Full-text available
Giant impacts dominate the final stages of terrestrial planet formation and set the configuration and compositions of the final system of planets. A giant impact is believed to be responsible for the formation of Earth's Moon, but the specific impact parameters are under debate. Because the canonical Moon‐forming impact is the most intensely studie...
Preprint
Giant impacts dominate the final stages of terrestrial planet formation and set the configuration and compositions of the final system of planets. A giant impact is believed to be responsible for the formation of Earth's Moon, but the specific impact parameters are under debate. Because the canonical Moon-forming impact is the most intensely studie...
Preprint
We discuss major challenges in modeling giant impacts between planetary bodies, focusing on the equations of state (EOS). During the giant impact stage of planet formation, rocky planets are melted and partially vaporized. However, most EOS models fail to reproduce experimental constraints on the thermodynamic properties of the major minerals over...
Preprint
Quantifying the energy budget of Earth in the first few million years following the Moon-forming giant impact is vital to understanding Earth's initial thermal state and the dynamics of lunar tidal evolution. After the impact, the body was substantially vaporized and rotating rapidly, very different from the planet we know today. The subsequent evo...
Article
Quantifying the energy budget of Earth in the first few million years following the Moon-forming giant impact is vital to understanding Earth's initial thermal state and the dynamics of lunar tidal evolution. After the impact, the body was substantially vaporized and rotating rapidly, very different from the planet we know today. The subsequent evo...
Article
Full-text available
Pressure is a key parameter in the physics and chemistry of planet formation and evolution. Previous studies have erroneously assumed that internal pressures monotonically increase with the mass of a body. Using smoothed particle hydrodynamics and potential field method calculations, we demonstrate that the hot, rapidly rotating bodies produced by...
Article
Full-text available
The giant impact hypothesis remains the leading theory for lunar origin. However, current models struggle to explain the Moon's composition and isotopic similarity with Earth. Here we present a new lunar origin model. High-energy, high-angular momentum giant impacts can create a post-impact structure that exceeds the corotation limit (CoRoL), which...
Article
During accretion, terrestrial bodies attain a wide range of thermal and rotational states, which are accompanied by significant changes in physical structure (size, shape, pressure and temperature profile, etc.). However, variations in structure have been neglected in most studies of rocky planet formation and evolution. Here, we present a new code...
Article
In the giant-impact hypothesis for lunar origin, the Moon accreted from an equatorial circum-terrestrial disk; however, the current lunar orbital inclination of five degrees requires a subsequent dynamical process that is still unclear. In addition, the giant-impact theory has been challenged by the Moon's unexpectedly Earth-like isotopic compositi...
Conference Paper
Existence of a partially molten layer at depth has been proposed to explain the lack of observed farside deep moonquakes, the observation of reflected phases from deep moonquakes, and the dissipation of tidal energy within the lunar interior. However, subsequent models explore the possibility that dissipation due to elevated temperatures alone can...

Citations

... There is no shortage of tidal evidence in the ancient rock record (Eriksson, 1977;Kvale & Archer, 1991;Räsänen et al., 1995;Kvale, 2006;Raaf & Boersma, 2007;James et al., 2010;Davis et al., 2012;Longhitano et al., 2012;Gugliotta et al., 2015;Rossi et al., 2016;Fritzen et al., 2019;Collins et al., 2020;Phillips et al., 2020), although some of the concepts developed from the study of ancient tidally-influenced sedimentary strata can be inconsistent with phenomena recognized in modern tidal environments (see discussion in Gugliotta & Saito, 2019;Cosma et al., 2020;Finotello et al., 2020). Numerical modelling of ancient basins (Wells et al., 2010;Hill et al., 2011;Mitchell et al., 2011;Collins et al., 2018;Dean et al., 2019;Collins et al., 2021;Daher et al., 2021) can help to test hypotheses formulated from the study of the rock record, reduce discrepancies between interpreted ancient and modern tides and tidal deposits, and improve the calibration of ancient tidal signals to astronomical parameters. Complementarily, the rock record can help to constrain model inputs and interpret results (Ward et al., 2015;Dean et al., 2019;Byrne et al., 2020;Haigh et al., 2020;Collins et al., 2021;Daher et al., 2021) and exclude anomalous 'numerically-viable' simulations (Ward et al., 2020). ...
... If a conventional SPH is used, no model can explain the composition of the Moon with canonical collision conditions. However, recently, Stewart et al. (2020) pointed out that the use of the Tillotson EoS for solids by Hosono et al. (2019) leads to a problem in evaluating the latent heat upon a phase change from solids to gas and proposed a modified EoS that is supposed to be able to treat all three phases of a material in a consistent way (see our comments on this equation of state in the next section). They did it by introducing a few parameters in the M-ANEOS EoS and explored its consequences for a GI modeling. ...
... Astronomy has a long history of employing such visualization, (see, e.g., Funkhouser, 1936), from abstract to cinematic (Aleo et al., 2020). ...
... The similarity in stable isotopes (e.g. for oxygen) between the Earth and Moon would be expected if Theia had a similar provenance to the proto-Earth. However, the stable isotope similarity with Earth is just one of several outstanding issues in lunar origin, including the large mass of the Moon, the similarity in Tungsten isotopes, the pattern of moderately volatile element depletion, and the inclination of the lunar orbit (Lock et al. 2020;Canup et al. 2021). Thus, factors other than material provenance must also be considered when discriminating between giant impact scenarios. ...
... The highest pressure and temperature conditions for core formation likely occur during and in the aftermath of giant impacts. As discussed above, in such events much of the core of the impacting body may not equilibrate efficiently with the proto-Earth's mantle (i.e., k ≪ 1, e.g., Carter et al., 2020;Landeau et al., 2016) and Earth's core likely inherited a strong memory of its earlier accretion. Therefore, the effect of core formation on the composition of Earth's mantle and core cannot be accurately determined using an "average" pressure and temperature of equilibration, as has often been done (e.g., Chidester et al., 2017), and the complicated dynamics of metal-silicate partitioning in accretionary processes must be considered. ...
... Ensuring compliance with the stringent environmental regulations have dictated to reduce the amount of conventional fossil fuels with their harmful effects, as well as the search for renewable energy resources, including that of solar and wind power. With respect to solar power, the incoming solar radiation to the Earth's surface is about 51% (174x1015 watt) of the total radiation reaches the upper atmosphere [1]. This enormous, abundant, free, non-polluting and renewable amount of energy needs to be harvested and utilized to compensate the gap between the increasing demand and the continuous shortage of the limited supply of the conventional energy resources [2]. ...
... Bodies with equal mass may have different internal pressures depending on their rotation speed (Lock & Stewart 2019). We assume no rotation, so the mass/radius values we infer are lower limits. ...
... The geikielite-ilmenite solid solution is the main titanium ore on Earth, and a mineral of key importance in models for the chemical and thermal evolution of the interior of Earth's Moon. Dynamical and geochemical models of Moon formation indicate that the Moon was covered by a deep magma ocean, shortly after its formation (e.g., Lock et al. 2018;Nakajima and Stevenson 2018;Steenstra et al. 2016Steenstra et al. , 2020. Experimental studies of the progressive solidification of this magma ocean indicate that Fe-rich geikielite-ilmenite crystals form late in the ocean's crystallization sequence in the shallow subsurface of the Moon, underneath the growing plagioclase-rich crust (Lin et al. 2017a(Lin et al. , b, 2020Charlier et al. 2018;Rapp and Draper 2018). ...
... The canonical giant Moon forming impact (left) by Canup and Asphaug (2001) vs the new concept of a synestia (right) by Lock and Stewart (2017); see text for further information. The left figure covers the first 23 hours from the impact, the color scale illustrates the thermal state of the matter with blue and dark green being condensed matter. ...
... Left figure from Canup and Asphaug (2001); right figure from Lock et al. (2018) impact onto a magma ocean dominated proto-Earth (Hosono et al. 2019) have also been shown to potentially be able to create the Moon. In addition, it was demonstrated that the angular momentum could have also been significantly altered after the Moon forming impact through lunar tidal evolution, offering more energetic events than previously thought (e.g., Canup 2012;Cuk and Stewart 2012;Wisdom and Tian 2015;Cuk et al. 2016;Tian et al. 2017). Kokubo and Genda (2010) even found that low velocity impacts, as in the canonical Moon forming scenario, are relatively rare, so that high energetic events might be favorable. ...