A two dimensional hydrodynamic model describing the solar wind interaction with the local interstellar medium, which surrounds the solar system, is used to study the heliosphere both as a steady-state- and dynamic structure. The finite volume method used to solve the associated system of hydrodynamic equations numerically is discussed in detail. Subsequently the steady state heliosphere is studied for both the case where the solar wind and the interstellar medium are assumed to consist of protons only, as well as the case where the neutral hydrogen population in the interstellar medium is taken into account. It is shown that the heliosphere forms as three waves, propagating away from the initial point of contact between the solar wind and interstellar matter, become stationary. Two of these waves become stationary at sonic points, forming the termination shock and bow shock respectively. The third wave becomes stationary as a contact discontinuity, called the heliopause. It is shown that the position and geometry of the termination shock, heliopause and bow shock as well as the plasma flow characteristics of the heliosphere largely depend on the dynamic pressure of either the solar wind or interstellar matter. The heliosphere is modelled as a dynamic structure, including both the effects of the solar cycle and short term variations in the solar wind observed by a range of spacecraft over the past ~ 30 years. The dynamic model allows the calculation of an accurate record of the heliosphere state over the past ~ 30 years. This record is used to predict the time at which the Voyager 2 spacecraft will cross the termination shock. Voyager 1 observations of 10 MeV cosmic ray electrons are then used in conjunction with a cosmic ray modulation model to constrain the record of the heliosphere further. It is shown that the dynamic hydrodynamic model describes the heliosphere accurately within a margin of error of ±0.7 years and ±3 AU. The model predicts that Voyager 2 crossed the termination shock in 2007, corresponding to preliminary results from observations indicating that the crossing occurred in August 2007. / Thesis (M.Sc. (Physics))--North-West University, Potchefstroom Campus, 2008.

The time-dependent modulation of galactic cosmic rays in the heliosphere is studied by computing intensities using a two-dimensional, time-dependent modulation model. The compound approach of Ferreira and Potgieter (2004), which describes changes in the cosmic ray transport coefficients over a solar cycle, is improved by introducing recent theoretical advances in the model. Computed intensities are compared with Voyager 1 and 2, IMP 8 and Ulysses proton observations in search of compatibility. It is shown that this approach gives realistic cosmic ray proton intensities on a global scale at Earth and along both Voyager spacecraft trajectories. The results show that cosmic ray modulation, in particular during the present polarity cycle, is not just determined by changes in the drift coefficient but is also dependent on changes in the diffusion coefficients. Furthermore, a comparison of computations to observations along the Voyager 1 and Voyager 2 trajectories illustrates that the heliosphere is asymmetrical. Assuming the latter, E > 70 MeV and 133-242 MeV cosmic ray proton intensities along Voyager 1 and 2 trajectories are predicted from 2012 onwards. It is shown that the computed intensities along Voyager 1 can increase with an almost constant rate since the spacecraft is close to the heliopause. However, the model shows that Voyager 2 is still under the influence of temporal solar activity changes because of the relatively large distance to the heliopause when compared to Voyager 1. Along the Voyager 2 trajectory the intensities should remain generally constant for the next few years and then should start to steadily increase. It is also found that without knowing the exact location of heliopause and transport parameters one cannot conclude anything about local interstellar spectra. The effect of a dynamic inner heliosheath width on cosmic ray modulation is also studied by implementing a time-dependent termination shock position in the model. This does not lead to improved compatibility with spacecraft observations so that a time-dependent termination shock along with a time-dependent heliopause position is required. The variation of the heliopause position over a solar cycle is found to be smaller compared to that of the termination shock. The model predicts the heliopause and termination shock positions along Voyager 1 in 2012 at 119 AU and 88 AU respectively and along Voyager 2 at 100 AU and 84 AU respectively. / Thesis (PhD (Space Physics))--North-West University, Potchefstroom Campus, 2013

The time-dependent modulation of galactic cosmic rays in the heliosphere is studied by computing intensities using a two-dimensional, time-dependent modulation model. The compound approach of Ferreira and Potgieter (2004), which describes changes in the cosmic ray transport coefficients over a solar cycle, is improved by introducing recent theoretical advances in the model. Computed intensities are compared with Voyager 1 and 2, IMP 8 and Ulysses proton observations in search of compatibility. It is shown that this approach gives realistic cosmic ray proton intensities on a global scale at Earth and along both Voyager spacecraft trajectories. The results show that cosmic ray modulation, in particular during the present polarity cycle, is not just determined by changes in the drift coefficient but is also dependent on changes in the diffusion coefficients. Furthermore, a comparison of computations to observations along the Voyager 1 and Voyager 2 trajectories illustrates that the heliosphere is asymmetrical. Assuming the latter, E > 70 MeV and 133-242 MeV cosmic ray proton intensities along Voyager 1 and 2 trajectories are predicted from 2012 onwards. It is shown that the computed intensities along Voyager 1 can increase with an almost constant rate since the spacecraft is close to the heliopause. However, the model shows that Voyager 2 is still under the influence of temporal solar activity changes because of the relatively large distance to the heliopause when compared to Voyager 1. Along the Voyager 2 trajectory the intensities should remain generally constant for the next few years and then should start to steadily increase. It is also found that without knowing the exact location of heliopause and transport parameters one cannot conclude anything about local interstellar spectra. The effect of a dynamic inner heliosheath width on cosmic ray modulation is also studied by implementing a time-dependent termination shock position in the model. This does not lead to improved compatibility with spacecraft observations so that a time-dependent termination shock along with a time-dependent heliopause position is required. The variation of the heliopause position over a solar cycle is found to be smaller compared to that of the termination shock. The model predicts the heliopause and termination shock positions along Voyager 1 in 2012 at 119 AU and 88 AU respectively and along Voyager 2 at 100 AU and 84 AU respectively. / Thesis (PhD (Space Physics))--North-West University, Potchefstroom Campus, 2013

A two dimensional hydrodynamic model describing the solar wind interaction with the local interstellar medium, which surrounds the solar system, is used to study the heliosphere both as a steady-state- and dynamic structure. The finite volume method used to solve the associated system of hydrodynamic equations numerically is discussed in detail. Subsequently the steady state heliosphere is studied for both the case where the solar wind and the interstellar medium are assumed to consist of protons only, as well as the case where the neutral hydrogen population in the interstellar medium is taken into account. It is shown that the heliosphere forms as three waves, propagating away from the initial point of contact between the solar wind and interstellar matter, become stationary. Two of these waves become stationary at sonic points, forming the termination shock and bow shock respectively. The third wave becomes stationary as a contact discontinuity, called the heliopause. It is shown that the position and geometry of the termination shock, heliopause and bow shock as well as the plasma flow characteristics of the heliosphere largely depend on the dynamic pressure of either the solar wind or interstellar matter. The heliosphere is modelled as a dynamic structure, including both the effects of the solar cycle and short term variations in the solar wind observed by a range of spacecraft over the past ~ 30 years. The dynamic model allows the calculation of an accurate record of the heliosphere state over the past ~ 30 years. This record is used to predict the time at which the Voyager 2 spacecraft will cross the termination shock. Voyager 1 observations of 10 MeV cosmic ray electrons are then used in conjunction with a cosmic ray modulation model to constrain the record of the heliosphere further. It is shown that the dynamic hydrodynamic model describes the heliosphere accurately within a margin of error of ±0.7 years and ±3 AU. The model predicts that Voyager 2 crossed the termination shock in 2007, corresponding to preliminary results from observations indicating that the crossing occurred in August 2007. / Thesis (M.Sc. (Physics))--North-West University, Potchefstroom Campus, 2008.

AFRIKAANS: Die uitgangspunt wat ten grondslag van hierdie studie lê, is die veronderstelling dat studies ten opsigte van die Middelnederlandse teks De reis van Sint Brandaan tot op hede min aandag geskenk het aan sekere belangrike temas. As gevolg van hierdie bepaalde leemtes, is die onderliggende betekenis van die teks moeilik bekombaar. Die doel van hierdie ondersoek is dus om die leemtes te vul wat nie voorheen in studies rakende hierdie teks ten volle aangespreek is nie, en veral dié in die Suid-Afrikaanse uitgawe deur De Klerk&Schutte (1996). In hoofstuk 1 word daar gefokus op Middeleeuse sienings oor die retoriek, met die proloog en die epiloog van De reis van Sint Brandaan as vertrekpunt vir nadere ondersoek. Die wêreld van die teks (die tekstuele wereld), sowel as die wêreld voor die teks (die wêreld van die hedendaagse leser) word primêr as invalshoeke gebruik. Om relevansie aan die invalshoeke te verleen, word daar gepoog om 'n verband aan te toon tussen Middeleeuse tegnieke van taaluitdrukking en modeme taalhandelingsbegrippe. Met al die faktore in gedagte, word daar ook ondersoek ingestel na die retoriek as manier van leserbeïnvloeding, en dat 'n resepsie-ondersoek nodig is om die moontlike gehoor van 'n teks te bepaal. In hoofstuk 2 word daar gefokus op die aanwesigheid van Middeleeuse simboliek en verskeie intertekste aanwesig in De reis van Sint Brandaan. Die invalshoek van hierdie hoofstuk berus hoofsaaklik by die wêreld agter die teks (die wêreld van die outeur), en die wêreld van die teks (die tekstuele wêreld). Dit kom ook aan die lig dat die betrokke teks deurtrek is met Christelike simboliek en intertekste wat op een of ander manier 'n verband met die Christelike geloof toon. Die strekking van die teks is primêr gewortel in Christelike simboliek, maar word ook sekondêr gekoppel aan ander soorte simboliek, soos dieresimboliek, plantsimboliek, geloofsimboliek (mites en legendes), getallesimboliek en natuursimboliek (son, maan, hitte, koue, wind, water). Baie van hierdie simboliek oorvleuel en sluit aan by die vele intertekste aanwesig wat 'n rol speel in die opbou van die verhaal. Deur die betrokke simboliek en intertekste aan te toon en te interpreteer, word 'n ryker betekenis aan hierdie teks verleen. Hoofstuk 3 en hoofstuk 4 is 'n uitvloeisel van hoofstuk 2. In hierdie twee hoofstukke word daar meer aandag verleen aan sekere belangrike aspekte wat tot dusver nie ten volle ontgin is nie, soos gesien in hoofstuk 2. Daar word gefokus word op die wêreld agter die teks (die wêreld van die outeur) en die wêreld van die teks (die tekstuele wêreld). In hoofstuk 3 word daar gepoog om die aard en rol van die duiwel en die hel in die Middeleeue aan te toon, soos gevind in De reis van Sint Brandaan. Daar word tot die slotsom gekom dat die duiwel in hierdie teks 'n verpersoonliking van die kwade (bose) is. 'n Bepaalde paradigmaverbreding word aangetoon wat daarop dui dat daar wegbeweeg word van net 'n spirituele konnotasie met die duiwel na 'n fisiese verpersoonliking. Daar word verder ondersoek ingestel na Middeleeuse voorstellings van die duiwel, strawwe en lokaliteite van die hel, die vagevuur, die hel as 'n tasbare ruimte, die verpersoonliking van die duiwel en die lot van 'n sondaar in die helse straf. In hoofstuk 4 word daar gepoog om die aard en rol van engele as boodskappers van God in die Middeleeue aan te toon, soos gevind in De reis van Sint Brandaan. Talle voorbeelde uit die betrokke teks dui op die rol van engele as tussengangers tussen God en die mens. Daar word verder ondersoek ingestel na die verskillende tipes engele gevind in die teks, en die verband tussen engele en visioene vanuit 'n Middeeuse tradisie en perspektief. Die aspekte van neutrale en gevalle engele, die begrip van "God sien" en die rol van engele as sielsbegeleiers na die hemel word aangetoon. ENGLISH: The point of departure which forms the basis of this study, is the supposition that studies with respect to the Middle Dutch text The voyage of Saint Brendan have, up to the present, paid little attention to certain important themes. As a result of this void the underlying meaning of this text is difficult to access. The purpose of this investigation is therefore to fill these gaps which former studies of this text have not fully addressed, most particularly those in the South African edition by De Klerk&Schutte (1996). In chapter 1 the focus is on medieval views on rhetoric with the prologue and epilogue of The voyage of Saint Brendan as the source for closer investigation. The point of departure used in this chapter lies mainly with the world of the text (the textual world) and the world in front of the text (the world of the modem reader). To give relevance to this angle of incidence, an attempt is made to show a connection between medieval concepts of speech act theory and modem speech act concepts. With all these factors in mind, rhetoric as a manner of reader influence is researched and an investigation of reception is necessary to determine the possible audience of a text. In chapter 2 the focus falls on the presence of medieval symbolism and various intertexts present in The voyage of Saint Brendan. The point of departure used in this chapter lies mainly with the world behind the text (the world of the author) and the world of the text (the textual world). It has come to light that this particular text is permeated with Christian symbolism and intertexts which, in one way or another, reveal a connection with the Christian faith. The tenor of this text is rooted primarily in Christian symbolism but is also, in a secondary way, coupled with other types of symbolism like animal symbolism, plant symbolism, symbolism of belief (myths and legends), number symbolism and symbolism in nature (sun, moon, heat, cold, wind, water). Much of this symbolism overlaps and joins the many intertexts present which playa role in the development of the story. By presenting and interpreting the particular symbolism and intertexts, a richer meaning of this text is achieved. Chapter 3 and chapter 4 arise as a result of what was set out in chapter 2. In these two chapters certain important aspects not covered in chapter two are addressed. The focus is on the world behind the text (the world of the author) and the world of the text (the textual world). In chapter 3 an attempt is made to present the nature and role of the devil and hell in medieval times with The voyage of Saint Brendan as example. The conclusion is reached that the devil in this text is a personification of evil. A broadening of this paradigm is demonstrated which suggests that there is a movement away from simply a spiritual connotation of the devil to a physical personification. Further research is instituted into medieval ideas concerning the devil, punishment and the location of hell, hell as a tangible space, the personification of the devil and the doom of the sinner in hell-fire. In chapter 4 an attempt is made to show the nature and role of angels as messengers of God in medieval times with the The voyage of Saint Brendan as example. Many examples from this text suggest the role of angels as that of mediators between God and man. Further investigation is instituted regarding the different types of angels found in the text and the connection between angels and visions from a medieval tradition and perspective. The aspects of neutral and fallen angels, the concept of "seeing God" and the role of angels as companions of the soul on its way to heaven are demonstrated. / Dissertation (MA (Afrikaans))--University of Pretoria, 2007. / Afrikaans / unrestricted

A place where Star Voyagers start their space journeys – Welcome to Spaceport Sweden.

On 10 February 1964 during naval night exercises off the south coast of Australia, the destroyer HMAS Voyager was lost after colliding with the aircraft carrier HMAS Melbourne. 82 men were killed. Following the collision, there were two Royal Commissions that sustained a political controversy that lasted for over four years. This thesis examines the loss of Voyager as a watershed in the operational and administrative history of the RAN and as a major event in Australian national history. This study has four broad objectives: to describe the loss of Voyager and the long running controversy that accompanied the disaster; to offer a convincing explanation of the causes of the collision and why two royal commissions concluded that the causes for the disaster were inexplicable; to assess the effect on the RAN, in terms of specific reforms and its influence on Service culture and professional ethos, of the disaster and the inquiries that followed; and finally, to analyse the loss of Voyager as a media and political cause celebre in Australian history. As so little has been written about Voyager using primary sources, this thesis was committed to detailed description of events as well as analysis of themes. This thesis draws upon an extensive body of primary source material in the form of official naval and Royal Commission records to which complete access was given; several large collections of private papers; over one hundred interviews with principal participants; and comprehensive files of press cuttings. The discussion seeks to demonstrate that a series of naval accidents preceding the loss of Voyager contributed in a substantial way to shaping the public reaction to, and political handling of, the disaster; that the method of inquiry played a major role in generating public and political disquiet; that the collision was both a catalyst and stimulus to change in naval operations and reform in naval administration; that the inability of two Royal Commissions to ascertain the causes of the collision and then to public suspicion of a cover-up; and, that the collision was most probably caused by the incorrect relaying of a tactical signal on the bridge of Voyager. The loss of HMAS Voyager appears to be a key event in the development of the RAN, not as a direct result of the collision or its causes, but as a consequence of its long and controversial aftermath.

Abstract  The purpose of this study is to analyze how the visual communication the scientists in charge of the Voyager project in 1977 chose to represent humanity on The Golden Record by using content analysis. This study is built on two questions of interest as well as a theoretical framework. Representation is investigated through Stuart halls ideas of representation and identity through Craig R. Scott - identity and identification. Furthermore, two methods have been used to answer our questions, quantitative content analysis and qualitative content analysis in combination.    Even though the initial intention was to show a diverse representation of humanity to a potential alien audience, the quantitative analysis showed an overrepresentation of men and people with caucasian descent. Adults between the ages 18-60 was in the majority, followed by children and lastly older people. Blacks, Asians, women and other groups are not as widely represented in the material. Although it might seem like the scientist has failed in their attempt to represent the world in 90 minutes, we argue that there are multiple circumstances which limited their ability to do so. The time pressure, historic context as well as the absents of large information sources in the 70s is the main reason why the material has an overrepresentation of caucasian men. Considering all circumstances, it becomes obvious that they did what they could in most circumstances when it comes to including a wide range of cultures. This being said, it still does not make it ethically justifiable to make a west-centered message with all of humanity as the sender. The message onboard Voyager should be seen as a form of invitation to earth and not an encyclopedia of mankind.

In this dissertation, I argue that contemporary cultural narratives are infused with ongoing ideologies of Euro-American imperialism that prioritizes Western bodies and ways of engaging with living and nonliving beings. This restriction severely hinders possible responses to the present environmental crisis of the era often called the 'Anthropocene' through constant creation and recreation of imperial power relations and the presumed superiority of Western approaches to living. Taking inspiration from postcolonial theorist Edward Said and theories of cultural studies and empire, I use interdisciplinary methods of narrative analysis to examine threads of imperial ideologies that are (re)told and glorified in popular American science fiction television series Star Trek: Voyager (1995-2001). Voyager follows the Star Trek tradition of exploring the far reaches of space to advance human knowledge, and in doing so writes Western imperial practices of difference into an idealized future. In chapters 2 through 5, I explore how the series highlights American exceptionalism, Manifest Destiny, a belief in endless linear progress, and the creation of a safe 'home' space amidst the 'wild' spaces of the Delta Quadrant. Each of these narrative features, as presented, rely on Western difference and superiority that were fundamental to past and present Euro-American imperial encounters and endeavors. Through the recreation of these ideologies of empire, Voyager normalizes, legitimizes, and universalizes imperial approaches to engagement with other lifeforms. In order to move away from this intertwined thread of past/present/future imperialism, in my final chapter I propose alternatives for ecofeminist-inspired narrative approaches that offer possibilities for non-imperial futures. As my analysis will demonstrate, Voyager is unable to provide new worlds free of imperial ideas, but the possibility exists through the loss of their entire world, and their need to constantly make and remake their world(s). World making provides opportunity for endless possibilities, and science fiction television has the potential to aid in bringing non-imperial worlds to life. These stories push beyond individual and anthropocentric attitudes toward life on earth, and although such stories will not likely be the immediate cause of change in this era of precarity, stories can prime us for thinking in non-imperial ways. / Doctor of Philosophy / In this dissertation, I argue that contemporary cultural narratives feature continuing Euro-American imperialism that prioritizes Western bodies and ideas. These embedded narratives recreate centuries of Western imperial encounters and attitudes, and severely hinder possible responses to the present environmental crisis of the 'modern' era. Taking inspiration from postcolonial theorist Edward Said, I use interdisciplinary methods of narrative analysis to examine threads of imperialism written into popular American science fiction television series Star Trek: Voyager (1995-2001). Voyager follows the Star Trek tradition of exploring the far reaches of space to advance human knowledge, and in doing so inscribes Western imperial practices of difference and power into an idealized future through features of exploration, modernity, and progress. In order to move away from these imperial modes of thinking, I then propose alternatives for new narrative approaches that offer possibilities for non-imperial futures. As my analysis will demonstrate, Voyager is unable to provide new worlds free of imperial ideas, but the possibility exists through the loss of their entire world, and their need to constantly make and remake their world(s). World making provides opportunity for endless possibility, and science fiction television has the potential to aid in bringing non-imperial worlds to life. These stories push beyond individual and human centered attitudes toward life on earth, and although such stories will not likely be the immediate cause of change in this era of environmental crisis, stories can prime us for thinking in non-imperial ways.

À partir de la culture du voyage et des études sur la mentalité du voyageur à la Renaissance, en comparant les récits de voyage de l’époque de Montaigne, notre recherche dévoile progressivement l’idée du voyage que Montaigne a conçue et pratiquée entre 1580 et 1581, en Allemagne, en Suisse et en Italie. Il considère ce long voyage à l’étranger comme une promenade, ou plutôt des promenades, en des lieux différents. Telle est la singularité dans la pensée montaignienne : la promenade est, par nature, une manière de marcher afin de se distraire. Cependant, Montaigne-voyageur transforme cette démarche en un art de voyager qui vise à éprouver du plaisir sur sa route pour rétablir une âme mélancolique, un état déséquilibré, raison initiale de son départ. Au niveau de la création littéraire, les deux ouvrages entreprennent deux genres distincts pour représenter le séjour à l’étranger de Montaigne. Le Journal de voyage, réalisé par son secrétaire et par Montaigne lui-même, représente le « moi-voyageur » du point de vue du voyageur sur la route. Quant aux Essais, en insérant certains événements de ce séjour à l’étranger, ils représentent un « Montaigne-voyageur » du point de vue de l’essayiste, qui effectue une introspection de son « moi-voyageur » et de son expérience de voyage après son retour en France. Ainsi, cette variation d’écriture entraîne un effet de décalage dans la lecture des deux ouvrages sur le même thème du voyage. Mais, « Montaigne-voyageur » joue également le rôle d’essayiste dans son parcours, au sens de l’expérimentation, et reprend sa place d’écrivain-essayiste dans ses Essais. / From travel culture and the study on the mentality of the traveler in the Renaissance, by comparing the travel writings at the time of Montaigne, this study progressively reveals the idea of travel that Montaigne conceived and practiced during 1580 and 1581, in Germany, Switzerland and Italy. He considers this long trip abroad as a walk, or rather walks, in different places. That’s the peculiarity in Montaigne’s thoughts: the walk is, by nature, a way of amusing oneself. However, Montaigne-traveller transforms this process into an art of travelling that seeks to feel pleasure on his road, in order to restore a melancholy soul and an unbalanced state, initial reason for his departure.In terms of literary creation, the two works convey two distinct genres of representing Montaigne’s stay abroad. The Montaigne’s Travel Journal, accomplished by his secretary and by Montaigne himself, represents the "me-traveller" from the point of view of the traveller on the road. And The Essays, by inserting some pieces during this stay abroad, they represent a "Montaigne-traveller" from the point of view of the essayist, who undertakes an introspection of his "me-traveller" and his travel experience after his return to France. Thus, this writing variation causes a shift in the reading of two books on the same theme of travel. But "Montaigne-traveller" also plays the role of the essayist during his journey, in the sense of experimentation, and resumes his position of writer-essayist in The Essays.