Immediate origin of the Moon as a post-impact satellite

The Moon is traditionally thought to have coalesced from the debris ejected by a giant impact onto the early Earth. However, such models struggle to explain the similar isotopic compositions of Earth and lunar rocks at the same time as the system’s angular momentum, and the details of potential impact scenarios are hotly debated. Above a high resolution threshold for simulations, we find that giant impacts can immediately place a satellite with similar mass and iron content to the Moon into orbit far outside Earth’s Roche limit. Even satellites that initially pass within the Roche limit can reliably and predictably survive, by being partially stripped and then torqued onto wider, stable orbits. Furthermore, the outer layers of these directly formed satellites are molten over cooler interiors and are composed of around 60% proto-Earth material. This could alleviate the tension between the Moon’s Earth-like isotopic composition and the different signature expected for the impactor. Immediate formation opens up new options for the Moon’s early orbit and evolution, including the possibility of a highly tilted orbit to explain the lunar inclination, and offers a simpler, single-stage scenario for the origin of the Moon

Swift: A modern highly-parallel gravity and smoothed particle hydrodynamics solver for astrophysical and cosmological applications

Numerical simulations have become one of the key tools used by theorists in all the fields of astrophysics and cosmology. The development of modern tools that target the largest existing computing systems and exploit state-of-the-art numerical methods and algorithms is thus crucial. In this paper, we introduce the fully open-source highly-parallel, versatile, and modular coupled hydrodynamics, gravity, cosmology, and galaxy-formation code Swift. The software package exploits hybrid task-based parallelism, asynchronous communications, and domain-decomposition algorithms based on balancing the workload, rather than the data, to efficiently exploit modern high-performance computing cluster architectures. Gravity is solved for using a fast-multipole-method, optionally coupled to a particle mesh solver in Fourier space to handle periodic volumes. For gas evolution, multiple modern flavours of Smoothed Particle Hydrodynamics are implemented. Swift also evolves neutrinos using a state-of-the-art particle-based method. Two complementary networks of sub-grid models for galaxy formation as well as extensions to simulate planetary physics are also released as part of the code. An extensive set of output options, including snapshots, light-cones, power spectra, and a coupling to structure finders are also included. We describe the overall code architecture, summarize the consistency and accuracy tests that were performed, and demonstrate the excellent weak-scaling performance of the code using a representative cosmological hydrodynamical problem with $\approx$$300$ billion particles. The code is released to the community alongside extensive documentation for both users and developers, a large selection of example test problems, and a suite of tools to aid in the analysis of large simulations run with Swift.Comment: 39 pages, 18 figures, submitted to MNRAS. Code, documentation, and examples available at www.swiftsim.co

Swift: A modern highly-parallel gravity and smoothed particle hydrodynamics solver for astrophysical and cosmological applications

Numerical simulations have become one of the key tools used by theorists in all the fields of astrophysics and cosmology. The development of modern tools that target the largest existing computing systems and exploit state-of-the-art numerical methods and algorithms is thus crucial. In this paper, we introduce the fully open-source highly-parallel, versatile, and modular coupled hydrodynamics, gravity, cosmology, and galaxy-formation code Swift. The software package exploits hybrid shared- and distributed-memory task-based parallelism, asynchronous communications, and domain-decomposition algorithms based on balancing the workload, rather than the data, to efficiently exploit modern high-performance computing cluster architectures. Gravity is solved for using a fast-multipole-method, optionally coupled to a particle mesh solver in Fourier space to handle periodic volumes. For gas evolution, multiple modern flavours of Smoothed Particle Hydrodynamics are implemented. Swiftalso evolves neutrinos using a state-of-the-art particle-based method. Two complementary networks of sub-grid models for galaxy formation as well as extensions to simulate planetary physics are also released as part of the code. An extensive set of output options, including snapshots, light-cones, power spectra, and a coupling to structure finders are also included. We describe the overall code architecture, summarise the consistency and accuracy tests that were performed, and demonstrate the excellent weak-scaling performance of the code using a representative cosmological hydrodynamical problem with ≈300 billion particles. The code is released to the community alongside extensive documentation for both users and developers, a large selection of example test problems, and a suite of tools to aid in the analysis of large simulations run with Swift

Will the Conscious–Subconscious Pacing Quagmire Help Elucidate the Mechanisms of Self-Paced Exercise? New Opportunities in Dual Process Theory and Process Tracing Methods

The extent to which athletic pacing decisions are made consciously or subconsciously is a prevailing issue. In this article we discuss why the one-dimensional conscious–subconscious debate that has reigned in the pacing literature has suppressed our understanding of the multidimensional processes that occur in pacing decisions. How do we make our decisions in real-life competitive situations? What information do we use and how do we respond to opponents? These are questions that need to be explored and better understood, using smartly designed experiments. The paper provides clarity about key conscious, preconscious, subconscious and unconscious concepts, terms that have previously been used in conflicting and confusing ways. The potential of dual process theory in articulating multidimensional aspects of intuitive and deliberative decision-making processes is discussed in the context of athletic pacing along with associated process-tracing research methods. In attempting to refine pacing models and improve training strategies and psychological skills for athletes, the dual-process framework could be used to gain a clearer understanding of (1) the situational conditions for which either intuitive or deliberative decisions are optimal; (2) how intuitive and deliberative decisions are biased by things such as perception, emotion and experience; and (3) the underlying cognitive mechanisms such as memory, attention allocation, problem solving and hypothetical thought

?When I Can Come on Time I'll be Ready to Finish?: Meanings of Lateness in Psychoanalytic Psychotherapy

This paper considers some aspects of the meaning of chronic lateness in psychoanalytic psychotherapy. The central role of time in psychoanalytic work and the significance of enactments around the analytic frame are considered. Using clinical material the writer explores how lateness can be understood as an expression of global difficulties in accepting and adapting to the demands of reality as well as a wide range of complex object-relationship difficulties. Some of the technical and countertransference complexities of dealing with lateness are discussed. Lateness is seen to project intolerable experiences into the therapist, to demonstrate the patient's intense difficulties in imagining and tolerating a productive couple, to re-enact a sadomasochistic dynamic from the patient's past and to re-encounter/re-address the patient's early experiences of rejection and oedipal rivalries. The eventual synchronization of therapist and patient's times is explored as a major achievement in the patient's increasing capacity for relating

Psychodynamic Counselling with Children and Young People: An Introduction

Introducing key psychodynamic theory, concepts and techniques, this text examines the challenges and opportunities of counselling adolescents and children. The book explores a wide variety of settings and contexts, from schools to community projects and mental health services. It is an invaluable guide for counsellors and therapists at all levels

Taking psychodynamic thinking 'home' to the workplace ? How can courses manage better the impact on student and employing agency?

In this article, consideration is given to a problem often experienced in relation to courses offering psychodynamic understanding to front-line workers with troubled clients ? the complexity for the student in taking the learning ?home? in a productive manner and the potential isolation of the student in, or alienation from, their workplace. A model of course delivery is described in which an active three-way partnership between student, course and workplace is fostered which enhances the students' learning, enables the workplace to benefit more fully from the course and enhances the effectiveness of the course in improving service to the ultimate client ? the service user

Freud and Klein in the Lion King

This paper is presented as a potential teaching resource for those starting out in their psychoanalytic understanding, whether aiming at clinical work or the academic study of psychoanalytic ideas. Some central ideas from Freud and Klein are illustrated and illuminated in an accessible way using the Disney film The Lion King. Key elements from the film are used to bring to life concepts such as infantile omnipotence, manic defences, Oedipal conflict, persecutory guilt, destructive envy, the superego, reparation and mourning. The story of Simba is taken as demonstrating universal struggles to overcome Oedipal rivalry and destructive envy in order to reach maturit