Journal articles on the topic 'Moon's gravity field'

This article is a logical and rational analysis of the physical phenomena produced by the three fields that are generated in space: gravity field; field of terrestrial nuclear magnetism; and orbital field. Eduardo Guimarães, through the studies of the three nuclear masses of the Sun's nucleus, the three nuclear masses of the moon's nucleus, and the three nuclear masses of the Earth's nucleus. We discover the three spatial fields that are generated in the solar system and in the planets. Then, from the general theory of the three fields of space, we can understand all the mechanics that generate the dynamics and kinematics of celestial bodies. So now we can understand why the smaller celestial bodies orbit the orbital field of the largest celestial bodies. So now we can understand why the planets produce orbits of elliptical motions, around the orbital field of the Sun. Then we understand the orbital mechanics of the little planet Mercury, and its abnormal orbit around the orbiting field of the Sun. Then Mercury has a perihelion precession of 2 degrees per century, due to an approximation of the perihelion of Mercury which is attracted by the micro-gravity of the Sun, generating an orbital deviation of 2 degrees per century. In the future the planet Mercury will lose energy from its nucleus and will not be able to make the orbital curve of the perihelion because it will have been attracted by the gravitational field of the Sun's nucleus. The fall of Mercury on the Sun will generate two thermonuclear explosions of SUPERNOVA. The first thermonuclear explosion of SUPERNOVA will be generated by the thermonuclear collision of the gravity mass attraction of Mercury debris with the Sun's nucleus. The second thermonuclear explosion of SUPERNOVA will be generated by the thermonuclear collision of attraction of the mass of orbital attraction of Mercury debris with the nucleus of the Sun. These two thermonuclear explosions of SUPERNOVA will generate two immense thermonuclear shockwaves that will devastate the entire fragile geo-biome of the solar system.

Abstract. This paper provides the overview of an integrated, multi-disciplinary effort to study the effects of the 29 March 2006 total solar eclipse on the environment, with special focus on the atmosphere. The eclipse has been visible over the Eastern Mediterranean, and on this occasion several research and academic institutes organised co-ordinated experimental campaigns, at different distances from eclipse totality and at various environments in terms of air quality. Detailed results and findings are presented in a number of component scientific papers included in a Special Issue of Atmospheric Chemistry and Physics. The effects of the eclipse on meteorological parameters, though very clear, were shown to be controlled by local factors rather than the eclipse magnitudes, and the turbulence activity near surface was suppressed causing a decrease in the Planetary Boundary Layer. In addition to the above, the decrease in solar radiation has caused change to the photochemistry of the atmosphere, with night time chemistry dominating. The abrupt "switch off" of the sun, induced changes also in the ionosphere (140 up to 220 km) and the stratosphere. In the ionosphere, both photochemistry and dynamics resulted to changes in the reflection heights and the electron concentrations. Among the most important scientific findings from the experiments undertaken has been the experimental proof of eclipse induced thermal fluctuations in the ozone layer (Gravity Waves), due to the supersonic movement of the moon's shadow, for the first time with simultaneous measurements at three altitudes namely the troposphere, the stratosphere and the ionosphere. Within the challenging topics of the experiments has been the investigation of eclipse impacts on ecosystems (field crops and marine plankton). The rare event of a total solar eclipse provided the opportunity to evaluate 1 dimensional (1-D) and three dimensional (3-D) radiative transfer (in the atmosphere and underwater), mesoscale meteorological, regional air quality and photochemical box models, against measurements.

Abstract The JUpiter Icy Moons Explorer is an ESA mission set for launch in 2023 April and arrival in the Jovian system in 2031 July to investigate Jupiter and its icy satellites with a suite of 10 instruments. The mission will execute several flybys of the icy moons Europa, Callisto, and Ganymede before ending the mission with a 9-month orbit around Ganymede. The 3GM experiment on board the spacecraft will exploit accurate range and Doppler (range-rate) measurements to determine the moons’ orbit, gravity field, and tidal deformation. The focus of this paper is on the retrieval of Europa’s and Callisto’s gravity field, without delving into the modeling of their interior structures. By means of a covariance analysis of the data acquired during flybys, we assess the expected results from the 3GM gravity experiment. We find that the two Europa flybys will provide a determination of the J 2 and C 22 quadrupole gravity field coefficients with an accuracy of 3.8 × 10−6 and 5.1 × 10−7, respectively. The 21 Callisto flybys will provide a determination of the global gravity field to approximately degree and order 7, the moon ephemerides, and the time-variable component of the gravitational tide raised by Jupiter on the moon. The k 2 Love number, describing the Callisto tidal response at its orbital period, can be determined with an uncertainty σ k2 ∼ 0.06, allowing us to distinguish with good confidence between a moon with or without an internal ocean. The constraints derived by 3GM gravity measurements can then be used to develop interior models of the moon.

Gravity plays a major role in the planetary formation and the development of the solar system. Gravity attraction is the essence of a power that holds and governs the universe; it makes the planets in the solar system revolve around the sun and the moons around their planets. Magnetic fields are also an important phenomenon in the solar system and beyond. Their causes are complex and have a variety of effects on their surroundings; they have become a critical tool for the exploration of solar system bodies. However, the study of the mechanisms of planets formation in the solar system is a difficult problem made more so by the inability to construct planetary-scale models for laboratory study. However, understanding the nature of the matter comprising the Solar System is crucial for understanding the mechanism that generates planetary magnetic fields and planetary gravity. In this study, a brief history about the development of planetary gravity is presented. Some data about the physical properties of planets in the solar system are presented and discussed. However, much work is still needed before the planetary gravity and planetary magnetic field processes are fully understood and full advantage be taken of the implications of both phenomena observations.

Abstract Changes in mass distribution affect the gravitational figure and reorient a planetary body’s surface with respect to its rotational axis. The mass anomalies in the present-day lunar gravity field can reveal how the figure and pole position have evolved over the Moon’s history. By examining sequentially each individual crater and basin, working backward in time order through the catalog of nearly 5200 craters and basins between 1200 and 20 km in diameter, we investigate their contribution to the lunar gravitational figure and reconstruct the evolution of the pole position by extracting their gravitational signatures from the present-day Moon. We find that craters and basins in this diameter range, which excludes South Pole–Aitken, have contributed to nearly 25% of the present-day power from the Moon’s degree-2 gravitational figure and resulted in a total displacement of the Moon’s pole by ∼10° along the Earth–Moon tidal axis over the past ∼4.25 billion years. This also implies that the geographical location of the Moon’s rotational pole has not moved since ∼3.8 Ga by more than ∼2° in latitude owing to impacts, and this has implications for the long-term stability of volatiles in the polar regions.

This article is a logical and rational analysis of the original nuclear matter, and of the structure that gave rise to the space architecture of the universe with galaxies, stars, the system of planets and moons, and arrives to original and inedited conclusions. After the so-called Big Bang of the universe arose the space, a new time count and the nuclear universe, governed by the actions of the physical properties of nuclear superconductivity space. The actions of the physical properties of superconductivity nuclear matter generate the spatial phenomenon of orbital superconductivity, which creates the orbit and space distance of the orbit between the moons with their planets, between the planets with their star, forming the system of planets, and among the stars creating the architecture of the galaxy. 4 The actions of the physical properties of superconductivity nuclear matter also generate the spatial phenomenon of gravity superconductivity, which creates the form and distance of gravity in moons, planets, planets, stars and comets, creating the actions of physics of the star and planet with gravity superconductivity. The actions of the physical properties of superconductivity nuclear matter also generates the spatial phenomenon of nuclear superconductivity of magnetism, which creates the magnetic pole and the spatial distance of the magnetic field. The nucleus of all stars, planets, moons, are made of matter, called, by mass of energy nuclear of superconductivity. All the materials that exist in the nuclear universe are produced, through the atomic decomposition of nuclear matter of superconductivity. The atomic decomposition of superconductivity nuclear matter reduces the nucleus and nuclear energy of spatial superconductivity. In the reduction of superconductivity nuclear energy there is a loss of the orbital superconductivity property of the moon and the planet. In the loss of the orbital superconductivity property of the moon and the planet, the moon is attracted by the superconductivity of the planet and reduces orbit until attracted by the superconductivity of the planet's gravitational field. The fall of the moon will destroy the planet or produce a crater because of the size of the planet. The fall of the moon on Jupiter will create an immense nuclear crater in which the diameter and depth will measure the extension of thousands of kilometers. The fall of the moon on Mars will create an immense nuclear explosion, and will destroy the planet. Majority of the planets of the galaxies and the universe have a time schedule of self-destruction in the fall of the moons. Most of the planets in the solar system have a time schedule of self-destruction in the fall of the moons.

Interplanetary missions have typically relied on Radio Science (RS) to recover gravity fields by detecting their signatures on the spacecraft trajectory. The weak gravitational fields of small bodies, coupled with the prominent influence of confounding accelerations, hinder the efficacy of this method. Meanwhile, quantum sensors based on Cold Atom Interferometry (CAI) have demonstrated absolute measurements with inherent stability and repeatability, reaching the utmost accuracy in microgravity. This work addresses the potential of CAI-based Gradiometry (CG) as a means to strengthen the RS gravity experiment for small-body missions. Phobos represents an ideal science case as astronomic observations and recent flybys have conferred enough information to define a robust orbiting strategy, whilst promoting studies linking its geodetic observables to its origin. A covariance analysis was adopted to evaluate the contribution of RS and CG in the gravity field solution, for a coupled Phobos-spacecraft state estimation incorporating one week of data. The favourable observational geometry and the small characteristic period of the gravity signal add to the competitiveness of Doppler observables. Provided that empirical accelerations can be modelled below the nm/s2 level, RS is able to infer the 6 × 6 spherical harmonic spectrum to an accuracy of 0.1–1% with respect to the homogeneous interior values. If this correlates to a density anomaly beneath the Stickney crater, RS would suffice to constrain Phobos’ origin. Yet, in event of a rubble pile or icy moon interior (or a combination thereof) CG remains imperative, enabling an accuracy below 0.1% for most of the 10 × 10 spectrum. Nevertheless, technological advancements will be needed to alleviate the current logistical challenges associated with CG operation. This work also reflects on the sensitivity of the candidate orbits with regard to dynamical model uncertainties, which are common in small-body environments. This brings confidence in the applicability of the identified geodetic estimation strategy for missions targeting other moons, particularly those of the giant planets, which are targets for robotic exploration in the coming decades.

AbstractA moon in synchronous rotation has longitudinal librations because of its non-spherical mass distribution and its elliptical orbit around the planet. We study the librations of Titan with periods of 14.7y and 29.5y and include deformation effects and the existence of a subsurface ocean. We take into account the fact that the orbit is not Keplerian and has other periodicities than the main period of orbital motion around Saturn due to perturbations by the Sun, other planets and moons. An orbital theory is used to compute the orbital perturbations due to these other bodies.We numerically evaluate the amplitude of the long-period librations for many interior structure models of Titan constrained by the mass, radius and gravity field. Measurements of the librations may give constraints on the interior structure of the icy satellites.

Very accurate theories of the libration of the Moon have been recently built by Migus (1980), Eckhardt (1981, 1982) and Moons (1982, 1984). All of them take into account the perturbation due to the Earth and the Sun on the motion of a rigid Moon about its center of mass. Additional perturbations (influence of the planets, shape of the Earth, elasticity of the Moon, …) are also often included.We present here the perturbations due to the shape of the Earth and the motion of the ecliptic plane on our theory which already contains planetary perturbations. This theory is completely analytical with respect to the harmonic coefficients of the lunar gravity field which is expanded in spherical harmonics up to the fourth order. The ELP 2000 solution (Chapront and Chapront-Touzé, 1983) supplies us with the motion of the center of mass of the Moon.

The knowledge of the interior structure (e.g., homogeneous, porous, or fractured) of Martian moons will lead to a better understanding of their formation as well as the early solar system. One approach to inferring the interior structure is via geodetic characteristics, such as gravity field and libration. Geodetic parameters can be derived from radiometric tracking measurements. A feasible mothership-CubeSat mission is proposed in this study with following purposes, (1) performing inter-sat Doppler measurements, (2) improving the understanding of Phobos as well as the dynamic model, (3) securing the mothership as well as the primary mission, and (4) supporting autonomous navigation, given the long distance between the Earth and Mars. This study analyzes budgets of volume, mass, power, deployment Δv, and link, and the Doppler measurement noise of the system, and gives a feasible design for the CubeSat. The accuracy of orbit determination and geodesy is revealed via the Monte-Carlo simulation of estimation considering all uncertainties. Under an ephemeris error of the Mars-Phobos system ranging from 0 to 2 km, the autonomous orbit determination delivers an accuracy ranging from 0.2 m to 21 m and 0.05 mm/s to 0.4 cm/s. The geodesy can return 2nd-degree gravity coefficients at an accuracy of 1‰, even in the presence of an ephemeris error of 2 km. The achieved covariance of gravity coefficients and libration amplitude indicates an excellent possibility to distinguish families of interior structures.

The article contains the overview of perspective satellite navigation systems for other planets and objects of Solar System. The example of this conception for the Moon is considered. The paper contains the brief overview of Moon exploration perspectives. An overview of countries’ space agencies programs on the Moon with automatic and human missions. The problem of lunar and cislunar navigation is considered, the ways of its solution are overviewed. One of the possible cases for lunar and cislunar navigation system realization is to create the satellite system similar to the Earth’s GNSS using the existing experiences. The main goal of the article is the conception of lunar receiver designed for the lunar navigation satellite system in case it is similar to GLONASS. The formulas’ simplifications because of Moon’s features are considered, including: absence of atmosphere and as a result absence of ionospheric and tropospheric delays; more simple gravity field because of small flattering (almost spherical shape). The conclusions on perspectives of the lunar navigation are made.

Some celestial bodies such as planets, moons and comets (here referred to as moons for simplicity) emit jets of material at speeds that in some instances are large enough to escape gravity. Previous investigations have shown this problem to be highly complex, e.g. involving multi-phase flows, phase changes, radiation and gas rarefaction effects. In order to learn from exploring a manageable parameter space, and to provide a limiting case, the present study considers a much simpler model situation in which the material of the jet is an inviscid, non-heat-conducting, perfect gas that issues radially at the surface of the moon with sonic velocity. Theoretical considerations show that the escape velocity of a gas is much smaller than that of a solid body. An analytical solution is obtained for the maximum height reached by a jet in steady flow. A computational parameter study of unsteady, inviscid, axisymmetric flow, including the effect of an atmosphere, provides a rich picture of the features and behaviour of the model jet. The deficit of the computed maximum steady-state penetration height below the isentropic theoretical value may be explained by the effect of the atmosphere and of dissipation in shock waves that occur in the computed flows. Many of the features of the gas jet are qualitatively mirrored in an experiment using a water flow analogy in which the gravitational field is simulated by a surface of suitable shape.

AbstractJupiter and its moons are a complex dynamical system that include several phenomena like tides interactions, moon’s librations and resonances. One of the most interesting characteristics of the Jovian system is the presence of the Laplace resonance, where the orbital periods of Ganymede, Europa and Io maintain a 4:2:1 ratio, respectively. It is interesting to study the role of the Laplace resonance in the dynamic of the system, especially regarding the dissipative nature of the tidal interaction between Jupiter and its closest moon, Io. The secular orbital evolution of the Galilean satellites, and so the Laplace resonance, is strongly influenced by the tidal interaction between Jupiter and its moons, especially with Io. Numerous theories have been proposed regarding this topic, but they disagree about the amount of dissipation of the system, therefore about the magnitude and the direction of the evolution of the system, mainly because of the lack of experimental data. The future ESA JUICE space mission is a great opportunity to solve this dispute. The data that will be collect during the mission will have an exceptional accuracy, allowing to investigate several aspects of the dynamics the system and possibly the evolution of Laplace Resonance of the Galilean moons. This work will focus on the gravity estimation and orbit reconstruction of the Galilean satellites by precise orbit determination of the JUICE mission during the Jovian orbital phase using radiometric data.

AbstractIn order to investigate the origin of Phobos and Deimos, the Japanese Martian Moons eXploration (MMX) mission is scheduled for launch in 2024. MMX will make comprehensive remote-sensing measurements of both moons and return regolith samples from Phobos to Earth. Geodetic measurements of gravity, shape, and rotation parameter of a body provides constraints on its internal structure reflecting its origin and evolution. Moments of inertia are important parameters to constrain the internal mass distribution, but they have not been well determined for the Martian moons yet. We discuss the mission requirements related to the moments of inertia to detect a potential heterogeneity of the mass distribution inside Phobos. We introduce mission instruments and operational strategies to meet the mission requirements. We present a preliminary imaging strategy from a quasi-satellite orbit for a base shape model that is expected to be created at the early stage of the mission. Geodetic products including ephemeris, gravity field, rotation parameter of Phobos, and spacecraft orbit are of importance not only for the geodetic study, but also for interpreting data from various mission instruments and selecting possible landing sites. Graphical Abstract

AbstractThe Earth-like planets and moons in our solar system have iron-rich cores, silicate mantles, and a basaltic crust. Differentiated icy moons can have a core and a mantle and an outer water–ice layer. Indirect evidence for several icy moons suggests that this ice is underlain by or includes a water-rich ocean. Similar processes are at work in the interiors of these planets and moons, including heat transport by conduction and convection, melting and volcanism, and magnetic field generation. There are significant differences in detail, though, in both bulk chemical compositions and relative volume of metal, rock and ice reservoirs. For example, the Moon has a small core [~ 0.2 planetary radii (RP)], whereas Mercury’s is large (~ 0.8 RP). Planetary heat engines can operate in somewhat different ways affecting the evolution of the planetary bodies. Mercury and Ganymede have a present-day magnetic field while the core dynamo ceased to operate billions of years ago in the Moon and Mars. Planets and moons differ in tectonic style, from plate-tectonics on Earth to bodies having a stagnant outer lid and possibly solid-state convection underneath, with implications for their magmatic and atmosphere evolution. Knowledge about their deep interiors has improved considerably thanks to a multitude of planetary space missions but, in comparison with Earth, the data base is still limited. We describe methods (including experimental approaches and numerical modeling) and data (e.g., gravity field, rotational state, seismic signals, magnetic field, heat flux, and chemical compositions) used from missions and ground-based observations to explore the deep interiors, their dynamics and evolution and describe as examples Mercury, Venus, Moon, Mars, Ganymede and Enceladus.

The tasks of studying the Moon require long-term functioning space systems. Most of the low selenocentric orbits are known to be unstable, which requires a propellant to maintain the orbital structure. For these orbits, the main disturbing factors are the off-center gravitational field of the Moon and the gravity of the Earth and the Sun. This paper analyzes the stability of low selenocentric orbits according to passive motion modeling and takes into account these main disturbing factors. We put forward a criterion for determining the stability of the orbit and used it to analyze the circular orbit of the Moon at an altitude of 100 kilometers. According to different initial data and different dates, we obtained ranges of the Moon’s orbits with good stability. At the same time, we analyzed the rate of change in the longitude of the ascending node, and found a stable low lunar orbit which can operate for a long time.

Since the late 1990s, W. G. Sebald’s innovative contribution to the genre of prose fiction has been the source of much academic scrutiny. His books Vertigo, The Rings of Saturn, The Emigrants and Austerlitz have provoked interest from diverse fields of inquiry: visual communication (Kilbourn; Patt; Zadokerski), trauma studies (Denham and McCulloh; Schmitz), and travel writing (Blackler; Zisselsberger). His work is also claimed to be a bastion for both modernist and postmodernist approaches to literature and history writing (Bere; Fuchs and Long; Long). This is in addition to numerous “guide to” type books, such as Mark McCulloh’s Understanding Sebald, Long and Whitehead’s W. G. Sebald—A Critical Companion, and the comprehensive Saturn’s Moons: A W. G. Sebald Handbook. Here I have only mentioned works available in English. I should point out that Sebald wrote in German, the country of his birth, and as one would expect much scholarship dealing with his work is confined to this language. In this article I focus on what is perhaps Sebald’s prototypical work, The Rings of Saturn. Of all Sebald’s prose fictional works The Rings of Saturn seems the example that best exhibits his innovative literary forms, including the use of lists. This book is the work of an author who is purposefully and imaginatively concerned with the nature of his vocation: what is it to be a writer? Crucially, he addresses this question not only from the perspective of a subject facing an existential crisis, but from the perspective of the documents created by writers. His works demonstrate a concern with the enabling role documents play in the thinking and writing process; how, for example, pen and paper are looped in with our capacity to reason in certain ways. Despite taking the form of fictional narratives, his books are as much motivated by a historical interest in how ideas and forms of organisation are transmitted, and how they evolve as part of an ecology; how humans become articulate within their surrounds, according to the contingencies of specific epochs and places. The Sebald critic J. J. Long accounts for this in some part in his description “archival consciousness,” which recommends that conscious experience is not simply located in the mind of a knowing, human subject, but is rather distributed between the subject and different technologies (among which writing and archives are exemplary).The most notable peculiarity of Sebald’s books lies in their abundant use of “non-syntactical” kinds of writing or inscription. My use of the term “non-syntactical” has its origins in the anthropological work of Jack Goody, who emphasises the importance of list making and tabulation in pre-literate or barely literate cultures. In Sebald’s texts, kinds of non-syntactical writing include lists, photographic images, tables, signatures, diagrams, maps, stamps, dockets and sketches. As I stress throughout this article, Sebald’s shifts between syntactical and non-syntactical forms of writing allows him to build up highly complex schemes of internal reference. Massimo Leone identifies something similar, when he notes that Sebald “orchestrates a multiplicity of voices and text-types in order to produce his own coherent discourse” (91). The play between multiplicity and coherence is at once a thematic and poetic concern for Sebald. This is to say, his texts are formal experiments with these contrasting tendencies, in addition to discussing specific historical situations in which they feature. The list is perhaps Sebald’s most widely used and variable form of non-syntactical writing, a key part of his formal and stylistic peculiarity. His lengthy sentences frequently spill over into catalogues and inventories, and the entire structure of his narratives is list-like. Discrete episodes accumulate alongside each other, rather than following a narrative arc where episodes of suspenseful gravity overshadow the significance of minor events. The Rings of Saturn details the travels of Sebald’s trademark, nameless, first person narrator, who recounts his trek along the Suffolk coastline, from Lowestoft to Ditchingham, about two years after the event. From the beginning, the narrative is framed as an effort to organise a period of time that lacks a coherent and durable form, a period of time that is in pieces, fading from the narrator’s memory. However, the movement from the chaos of forgetting to the comparatively distinct and stable details of the remembered present does not follow a continuum. Rather, the past and present are both constituted by the force of memory, which is continually crystallising and dissolving. Each event operates according to its own specific arrangement of emphasis and forgetting. Our experience of memory in the present, or recollective memory, is only one kind of memory. Sebald is concerned with a more pervasive kind of remembering, which includes the vectorial existence of non-conscious, non-human perceptual events; memory as expressed by crystals, tree roots, glaciers, and the nested relationship of fuel, fire, smoke, and ash. The Rings of Saturn is composed of ten chapters, each of which is outlined in table form at the book’s beginning. The first chapter appears as: “In hospital—Obituary—Odyssey of Thomas Browne’s skull—Anatomy lecture—Levitation—Quincunx—Fabled creatures—Urn burial.” The Rings of Saturn is of course hardly exceptional in its use of this device. Rather, it is exemplary concerning the repeated emphasis on the tension between syntactical and non-syntactical forms of writing, among which this chapter breakdown is included. Sebald continually uses the conventions of bookmaking in subtle though innovative ways. Each of these horizontally linked and divided indices might put the reader in mind of Thomas Browne’s urns, time capsules from the past, the unearthing of which is discussed in the book’s first chapter (25). The chapter outlines (and the urns) are containers that preserve a fragmentary and suggestive history. Each is a perspective on the narrator’s travels that abstracts, arranges, and uniquely refers to the narrative elaborations to come.As I have already stressed, Sebald is a writer concerned with forms of organisation. His works account for a diverse range of organisational forms, some of which instance an overt, chronological, geometric, or metrical manipulation of space and time, such as grids, star shapes, and Greenwich Mean Time. This contrasts with comparatively suggestive, insubstantial, mutable forms, including various meteorological phenomena such as cloudbanks and fog, dust and sand, and as exemplified in narrative form by the haphazard, distracted assemblage of events featured in dreams or dream logic. The relationship between these supposedly opposing tendencies is, however, more complex and paradoxical than might at first glance appear. As Sebald warily reminds us in his essay “A Little Excursion to Ajaccio,” despite our wishes to inhabit periods of complete freedom, where we follow our distractions to the fullest possible extent, we nonetheless “must all have some more or less significant design in view” (Sebald, Campo 4). It is not so much that we must choose, absolutely, between form and formlessness. Rather, the point is to understand that some seemingly inevitable forms are in fact subject to contingencies, which certain uses deliberately or ignorantly mask, and that simplicity and intricacy are often co-dependent. Richard T. Gray is a Sebald critic who has picked up on the element in Sebald’s work that suggests a tension between different forms of organisation. In his article “Writing at the Roche Limit,” Gray notes that Sebald’s tendency to emphasise the decadent aspects of human and natural history “is continually counterbalanced by an insistence on order and by often extremely subtle forms of organization” (40). Rather than advancing the thesis that Sebald is exclusively against the idea of systematisation or order, Gray argues that The Rings of Saturn models in its own textual make-up an alternative approach to the cognitive order(ing) of things, one that seeks to counter the natural tendency toward entropic decline and a fall into chaos by introducing constructive forces that inject a modicum of balance and equilibrium into the system as a whole. (Gray 41)Sebald’s concern with the contrasting energies exemplified by different forms extends to his play with syntactical and non-syntactical forms of writing. He uses lists to add contrast to his flowing, syntactically intricate sentences. The achievement of his work is not the exclusive privileging of either the list form or the well-composed sentence, but in providing contexts whereby the reader can appreciate subtle modulations between the two, thus experiencing a more dynamic and complex kind of narrative time. His works exhibit an astute awareness of the fact that different textual devices command different experiences of temporality, and our experience of temporality in good part determines our metaphysics. Here I consider two lists featured in The Rings of Saturn, one from the first chapter, and one from the last. Each shows contrasting tendencies concerning systems of organisation. Both are attributable to the work of Thomas Browne, “who practiced as a doctor in Norwich in the seventeenth century and had left a number of writings that defy all comparison” (Sebald, Rings 9). The Rings of Saturn is in part a dialogue across epochs with the sentiments expressed in Browne’s works, which, according to Bianca Theisen, preserve a kind of reasoning that is lost in “the rationalist and scientific embrace of a devalued world of facts” (Theisen 563).The first list names the varied “animate and inanimate matter” in which Browne identifies the quincuncial structure, a lattice like arrangement of five points and intersecting lines. The following phenomena are enumerated in the text:certain crystalline forms, in starfish and sea urchins, in the vertebrae of mammals and the backbones of birds and fish, in the skins of various species of snake, in the crosswise prints left by quadrupeds, in the physical shapes of caterpillars, butterflies, silkworms and moths, in the root of the water fern, in the seed husks of the sunflower and the Caledonian pine, within young oak shoots or the stem of the horse tail; and in the creations of mankind, in the pyramids of Egypt and the mausoleum of Augustus as in the garden of King Solomon, which was planted with mathematical precision with pomegranate trees and white lilies. (Sebald, Rings 20-21)Ostensibly quoting from Browne, Sebald begins the next sentence, “Examples might be multiplied without end” (21). The compulsion to list, or the compulsiveness expressed by listing, is expressed here in a relationship of dual utility with another, dominant or overt, kind of organisational form: the quincunx. It is not the utility or expressiveness of the list itself that is at issue—at least in the version of Browne’s work preserved here by Sebald. In W. G. Sebald: Image, Archive, Modernity, Long notes the historical correspondences and divergences between Sebald and Michel Foucault (2007). Long interprets Browne’s quincunx as exemplifying a “hermeneutics of resemblance,” whereby similarities among diverse phenomena are seen as providing proof of “the universal oneness of all things” (33). This contrasts with the idea of a “pathological nature, autonomous from God,” which, according to Long, informs Sebald’s transformation of Browne into “an avatar of distinctly modern epistemology” (38). Long follows Foucault in noting the distinction between Renaissance and modern epistemology, a distinction in good part due to the experimental, inductive method, the availability of statistical data, and probabilistic reasoning championed in the latter epoch (Whitehead; Hacking). In the book’s final chapter, Sebald includes a list from Browne’s imaginary library, the “Musæum Clausium.” In contrast to the above list, here Sebald seems to deliberately problematise any efforts to suggest an abstract uniting principle. There is no evident reason for the togetherness of the discrete things, beyond the mere fact that they happen to be gathered, hypothetically, in the text (Sebald, Rings 271-273). Among the library’s supposed contents are:an account by the ancient traveller Pytheas of Marseilles, referred to in Strabo, according to which all the air beyond thule is thick, condensed and gellied, looking just like sea lungs […] a dream image showing a prairie or sea meadow at the bottom of the Mediterranean, off the coat of Provence […] and a glass of spirits made of æthereal salt, hermetically sealed up, of so volatile a nature that it will not endure by daylight, and therefore shown only in winter or by the light of a carbuncle or Bononian stone. (Sebald, Rings 272-73)Unlike the previous example attributed to Browne, here the list coheres according to the tensions of its own coincidences. Sebald uses the list to create spontaneous organisations in which history is exhibited as a complex mix of fact and fantasy. More important than the distinction between the imaginary and the real is the effort to account for the way things uniquely incorporate aspects of the world in order to be what they are. Human knowledge is a perspective that is implicated in, rather than excluded from, this process.Lists move us to puzzle over the criteria that their togetherness implies. They might be used inthe service of a specific paradigm, or they might suggest an imaginable but as yet unknown kind of systematisation; a specific kind of relationship, or simply the possibility of a relationship. Take, for example, the list-like accumulation of architectural details in the following description of the decadent Sommerleyton Hall, featured in chapter II: There were drawing rooms and winter gardens, spacious halls and verandas. A corridor might end in a ferny grotto where fountains ceaselessly plashed, and bowered passages criss-crossed beneath the dome of a fantastic mosque. Windows could be lowered to open the interior onto the outside, and inside the landscape was replicated on the mirror walls. Palm houses and orangeries, the lawn like green velvet, the baize on the billiard tables, the bouquets of flowers in the morning and retiring rooms and in the majolica vases on the terrace, the birds of paradise and the golden peasants on the silken tapestries, the goldfinches in the aviaries and the nightingales in the garden, the arabesques in the carpets and the box-edged flower beds—all of it interacted in such a way that one had the illusion of complete harmony between the natural and the manufactured. (Sebald, Rings 33-34)This list shifts emphasis away from preconceived distinctions between the natural and the manufactured through the creation of its own unlikely harmony. It tells us something important about the way perception and knowledge is ordered in Sebald’s prose. Each encounter, or historically specific situation, is considered as though it were its own microworld, its own discrete, synecdochic realisation of history. Rather than starting from the universal or the meta-level and scaling down to the local, Sebald arranges historically peculiar examples that suggest a variable, contrasting and dynamic metaphysics, a motley arrangement of ordering systems that each aspire to but do not command universal applicability. In a comparable sense, Browne’s sepulchral urns of his 1658 work Urn Burial, which feature in chapter I, are time capsules that seem to create their own internally specific kind of organisation:The cremated remains in the urns are examined closely: the ash, the loose teeth, some long roots of quitch, or dog’s grass wreathed about the bones, and the coin intended for the Elysian ferryman. Browne records other objects known to have been placed with the dead, whether as ornament or utensil. His catalogue includes a variety of curiosities: the circumcision knives of Joshua, the ring which belonged to the mistress of Propertius, an ape of agate, a grasshopper, three-hundred golden bees, a blue opal, silver belt buckles and clasps, combs, iron pins, brass plates and brazen nippers to pull away hair, and a brass Jews harp that last sounded on the crossing over black water. (Sebald, Rings 25-26)Regardless of our beliefs concerning the afterlife, these items, preserved across epochs, solicit a sense of wonder as we consider what we might choose for company on our “last journey” (25). In death, the human body is reduced to a condition of an object or thing, while the objects that accompany the corpse seem to acquire a degree of potency as remnants that transcend living time. Life is no longer the paradigm through which to understand purpose. In their very difference from living things these objects command our fascination. Eric Santner coins the term “undeadness” to name the significance of this non-living agency in Sebald’s prose (Santner xx). Santner’s study places Sebald in a linage of German-Jewish writers, including Walter Benjamin, Franz Kafka, and Paul Celan, whose understanding of “the human” depends crucially on the concept of “the creature” or “creatureliness” (Santner 38-41). Like the list of items contained within Sommerleyton Hall, the above list accounts for a context in which ornament and utensil, nature and culture, are read according to their differentiated togetherness, rather than opposition. Death, it seems, is a universal leveller, or at least a different dimension in which symbol and function appear to coincide. Perhaps it is the unassuming and convenient nature of lists that make them enduring objects of historical interest. Lists are a form of writing to which we appeal for immediate mnemonic assistance. They lack the artifice of a sentence. While perhaps not as interesting in the present that is contemporary with their usefulness (a trip to the supermarket), with time lists acquire credibility due to the intimacy they share with mundane, diurnal concerns—due to the fact that they were, once upon a time, so useful. The significance of lists arrives anachronistically, when we look back and wonder what people were really up to, or what our own concerns were, relatively free from fanciful, stylistic adornment. Sebald’s democratic approach to different forms of writing means that lists sit alongside the esteemed poetic and literary efforts of Joseph Conrad, Algernon Swinburne, Edward Fitzgerald, and François René de Chateaubriand, all of whom feature in The Rings of Saturn. His books make the exclusive differences between literary and non-literary kinds of writing less important than the sense of dynamism that is elicited through a play of contrasting kinds of syntactical and non-syntactical writing. The book’s closing chapter includes a revealing example that expresses these sentiments. After tracing over a natural history of silk, with a particular focus on human greed and naivety, the narrative arrives at a “pattern book” that features strips of colourful silk kept in “the small museum of Strangers Hall” (Sebald, Rings 283). The narrator notes that the silks arranged in this book “were of a truly fabulous variety, and of an iridescent, quite indescribable beauty as if they had been produced by Nature itself, like the plumage of birds” (283). This effervescent declamation continues after a double page photograph of the pattern book, which is described as a “catalogue of samples” and “leaves from the only true book which none of our textual and pictorial works can even begin to rival” (286). Here we witness Sebald’s inclusive and variable understanding as to the kinds of thing a book, and writing, can be. The fraying strips of silk featured in the photograph are arranged one below the other, in the form of a list. They are surrounded by ornate handwriting that, like the strips of silk, seems to fray at the edges, suggesting the specific gestural event that occasioned the moment of their inscription—something which tends to be excluded in printed prose. Sebald’s remarks here are not without a characteristic irony (“the only true book”). However, in the greatercontext of the narrative, this comment suggests an important inclination. Namely, that there is much scope yet for innovative literary forms that capture the nuances and complexity of collective and individual histories. And that writing always includes, though to varying degrees obscures, contrasting tensions shared among syntactical and non-syntactical elements, including material and gestural contingencies. Sebald’s works remind us of what potentials might lay ahead for books if the question of what writing can be is asked continually as part of a writer’s enterprise.ReferencesBere, Carol. “The Book of Memory: W. G. Sebald’s The Emigrants and Austerlitz.” Literary Review, 46.1 (2002): 184-92.Blackler, Deane. Reading W. G. Sebald: Adventure and Disobedience. Rochester, New York: Camden House, 2007. Catling Jo, and Richard Hibbitt, eds. Saturn’s Moons: A W. G. Sebald Handbook. Oxford: Legenda, 2011.Denham, Scott and Mark McCulloh, eds. W. G. Sebald: History, Memory, Trauma. Berlin: Walter de Gruyter, 2006. Fuchs, Anne and J. J. Long, eds. W. G. Sebald and the Writing of History. Würzburg: Königshausen & Neumann, 2007. Goody, Jack. The Logic of Writing and the Organization of Society. Cambridge: Cambridge UP, 1986. Gray, Richard T. “Writing at the Roche Limit: Order and Entropy in W. G. Sebald’s The Rings of Saturn.” The German Quarterly 83.1 (2010): 38-57. Hacking, Ian. 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