In this licentiate thesis, I consider debris disks from an observational, astronomical viewpoint, but also discuss a potential astrobiological application. Debris disks are essentially disks of dust and rocks around main-sequence stars, analogue to the Kuiper- or the asteroid belt in our solar system. Their observation and theoretical modeling can help to constrain planet formation models and help in the understanding of the history of the solar system. After a general introduction into the field of debris disks and some basic debris disk physics, the thesis concentrates on the observation of gas in debris disks. The possible origins of this gas and its dynamics are discussed and it is considered what it can tell us about the physical conditions in the disk and possibly about the dust composition. In this way, the paper associated with this thesis (dealing with the gas in the β Pic debris disk) is set into context. More in detail, we observed the CII emission originating from the carbon-rich β Pic disk with Herschel HIFI and attempted to constrain the spatial distribution of the gas from the shape of the emission line. This is necessary since the gas production mechanism is currently unknown, but can be constraint by obtaining information about the spatial profile of the gas. The last part of the thesis describes our preliminary studies of the possibility of a debris disk containing biomarkers, created by a giant impact on a life-bearing exoplanet.

This dissertation uses Actor Network Theory (ANT) and Stark and Bainbridge's rational choice theory of religion to analyze an established but controversial branch of science and technology, the Search for Extraterrestrial Intelligence (SETI). Of particular interest are the cultural, and sometimes religious, assumptions that its creators have built into it. The purpose of this analysis is not to discredit SETI, but instead to show how SETI, along with other avant-garde scientific projects, is founded, motivated, and propelled by many of the same types of values and visions for the future that motivate the founders of religious groups. I further argue that the utopian zeal found in SETI and similar movements is not aberrant, but instead common, and perhaps necessary, in many early-stage projects, whether technical or spiritual, which lack a clear near-term commercial or social benefit. / Ph. D.

Space radiation and its effects on human life and sensitive equipment are of concern to a safe exploration of space. Radiation fields are modified in quality and quantity by intervening shielding materials. The modification of space radiation by shielding materials is modeled by deterministic transport codes using the Boltzmann transport equation. Databases of cross sections for particle production are needed as input for transport codes. A simple model of nucleon-nucleon interactions is developed and used to derive differential and total cross sections. The validity of the model is verified for proton-proton elastic scattering and applied to delta-resonance production. Additionally, a comprehensive validation program of the nucleus-nucleus fragmentation cross section models NUCFRG2 and QMSFRG is performed. A database of over 300 experiments was assembled and used to compare to model fragmentation cross sections.

AFRIKAANS: Die Antieke ruimtevaarder-teorie stel voor dat wesens uit die ruimte die Aarde in die antieke verlede besoek het. Hierdie wesens was betrokke by die vroeë geskiedenis van die planet. Hulle het bewoonbare toestande geskep asook menslike intelligensie deur 'n proses van genetiese ingenieurswese. Hul besoeke is opgeteken en deur mense oorgelewer in godsdienste, mitologieë en antieke legendes. Hul teenwoordigheid is ook nog waarneembaar in antieke fisiese oorblyfsels. Voorstanders van die Ruimtevaarderteorie bied dit aan as 'n wetenskaplike hipotese en as die "mees perfekte algemene noemer van alle tye" wat 'n moderne verklaring vir die oer-godsdiens bied. Afdeling A van die studie bied 'n oorsig oor die teorie en die bewyse wat daarvoor aangebied word. Daar word aangetoon dat, hoewel die meeste van die postulate nie deur die moderne wetenskap as "onsinnig" beskou word nie, dit nie oortuig as 'n werkbare wetenskaplike teorie nie. Omdat daar weinig verskille tussen die basiese onderneming van die wtenskap en die godsdiens bestaan (beide vertrek vanaf onbewysbare aannames om waargenome data te verklaar) word daar vermoed dat die Antieke ruimtevaarder-teorie eerder funksioneer op die vlak van religieusiteit. Hierdie tese word ondersoek in Afdeling B van die studie: Daar word voorgestel dat die Fenomenologiese metode van godsdienswetenskaplike ondersoek, wat poog om 'n fenomeen te verstaan nie soos dit manifesteer nie, maar op die dieper vlak van die funksie en betekenins daarvan, die mees paslike metode vir die ondersoek is. (p> Met gebruikmaking van die insigte van 'n Fenomenologiese benadering, word aangedui dat die Antieke ruimtevaarder-teorie funksioneer as 'n godsdienstige beweging met eienskappe van 'n kulte en 'n nieu-mitologie. Die aanvaarbaarheid van die teorie vir die vele volgelinge daarvan, en die gepaardgaande groei van die bcweging wat dit propageer, word verklaar uit 'n kombinasie van sosiologiese en psigologiese faktore wat aan die werk is in die moderne Westerse beskawing. Vanuit 'n fenomenologiese gesigspunt word gekonkludeer dat die Ruimtevaardcrteorie baie suksesvol op religieuse vlak is. Dit slaag daarin om die Bybel weer "geloofwaardig" te maak en skep weer 'n "kosmiese raamwerk" vir die betekenis van die menslike bestaan. Die teorie kan ook beskou word as 'n prysenswaardige poging tot die sintetisering van godsdiens en die modeme wetenskap vir die aanhangers daarvan, en om die geestelike behoeftes van mense in 'n verwarrende en verwarde wêreld aan te spreek. In 'n slotafdeling word die bevindinge van die studie teologies oorweeg en word die waarde daarvan vir die Chrislelike godsdiens aangetoon. ENGLISH: The Ancient astronaut theory proposes that beings from outer space came to Earth in the distant past. These beings were involved in the early history of the planet: They created habitable conditions and human intelligence by genetic engineering. Their visits were recorded and handed down by humans in their religions, mythologies and ancient legends. Their presence is also visible in ancient physical remains. Proponents present the Astronaut theory as a scientific hypothesis and as "the most perfect common denominator of all time", allowing a modem explanation for old-time religion: Section A of the study provides an overview of the theory and the evidence presented in support of it. It is shown that, although many of the postulates are being accepted by modem science as "not unreasonable", it is not convincing as a workable scientific theory. Since there is little difference between the basic enterprises of science and religion (both departing from unproven suppositions to explain perceived data) it is suspected that the Astronaut theory rather functions on a level of religiosity. This thesis is investigated in Section 8 of the study: It is proposed that the Phenomenological method of studying religion, which attempts to understand a phenomenon not in the way it manifests itself, but on the deeper level of its function and meaning, is the most appropriate for this investigation. Using the insights of a Phenomeno!ogical approach, it is shown that the Ancient astronaut theory functions as a religious movement with attributes of a cult and a new-mythology. The acceptability of the theory for its many followers and the resulting growth of the movement that proposes it, is explained from a combination of social and psychological factors at work in Western society. From a phenomenological point of view it is concluded that the Astronaut theory may be considered very successful on a religious level: It succeeds in making the Bible "respectable" again and it recreates a "cosmic framework" for the meaning of human existence. The theory may also be considered a praiseworthy attempt to synthesise religion and modem science for its supporters and to address the spiritual needs of man in a confusing and confused world. In a final section of the study, the results are being considered theologically and their value. being shown for Christianity. / Thesis (PhD (Science of Religion))--University of Pretoria, 2007. / Science of Religion and Missiology / unrestricted

<p> Inclement challenges of a changing climate and humanity's desire to explore extraterrestrial environments both necessitate efficient methods to obtain freshwater. To accommodate next generation water technology, there is a need for understanding and defining the energy efficiency for unconventional water sources over a broad range of environments. Exergy analysis provides a common description for efficiency that may be used to evaluate technologies and water sources for energy feasibility. This work uses robust thermodynamic theory coupled with atmospheric and planetary data to define water capture efficiency, explore its variation across climate conditions, and identify technological niches and development needs.  </p> <p><br></p> <p> We find that desalinating saline liquid brines, even when highly saline, could be the most energetically favorable option for obtaining water outside of Earth. The energy required to access water vapor may be four to ten times higher than accessing ice deposits, however it offers the capacity for decentralized systems. Considering atmospheric water vapor harvesting on Earth, we find that the thermodynamic minimum is anywhere from 0x (RH≥ 100%) to upwards of 250x (RH<10\%) the minimum energy requirement of seawater desalination. Sorbents, modelled as metal organic frameworks (MOFs), have a particular niche in arid and semi-arid regions (20-30%). Membrane-systems are best at low relative humidity and the region of applicability is strongly affected by the vacuum pumping efficiency. Dew harvesting is best at higher humidity and fog harvesting is optimal when super-saturated conditions exist. Component (e.g., pump, chiller, etc.) inefficiencies are the largest barrier in increasing process-level efficiency and strongly impact the regions optimal technology deployment. The analysis elucidates a fundamental basis for comparing water systems energy efficiency for outer space applications and provides the first thermodynamics-based comparison of classes of atmospheric water harvesting technologies on Earth.</p>

Die Ramanspektroskopie (RS) ist eine analytische Technik, die in Folge einer optischen Anregung eines Stoffes materialspezifische Informationen über dessen molekulare Schwingungen und Kristallstruktur liefert. Da sowohl Minerale als auch biologische Materialien untersucht werden können, ist die RS in der Weltraumforschung von besonderem Interesse. So werden im Jahr 2020 gleich zwei Marsrover (ExoMars und Mars 2020) Ramanspektrometer mitführen, deren Aufgabe unter anderem die Detektion von Spuren von vergangenem oder gegenwärtigem extraterrestrischen Leben sein wird. Die Charakterisierung von stark lumineszierenden biologischen Proben und Mineralen stellt eine der größten Herausforderungen in der konventionellen RS dar. Daher beschäftigt sich diese Dissertation mit dem Problem der Lumineszenz in der RS. Dazu wird das Potenzial von fünf verschiedenen ramanspektroskopischen Techniken zur Handhabung der Lumineszenz evaluiert. Diese Techniken beinhalten (i) die Auswahl von verschiedenen Anregungswellenlängen (325 nm, 532 nm, 785 nm, 1064 nm), welche auf dem Konzept der spektralen Trennung des Lumineszenz- und Ramansignals basiert. (ii) Eine Alternative ist das Photobleichen, wobei die Lumineszenz durch eine lange Belichtungszeit unterdrückt wird. (iii) Eine weitere Methode für die spektrale Separation von Raman- und Lumineszenzphotonen ist die anti-Stokes RS. (iv) Bei der SERDS Technik werden zwei leicht verschobene Anregungswellenlängen verwendet. (v) Abschließend erfolgt die Untersuchung der Streu- und Emissionsstrahlung in der Zeitdomäne. Die Ergebnisse dieser Arbeit zeigen, dass es keine universelle Lösung gibt um das Problem der Lumineszenz in der RS zu überwinden. Allerdings weist die Verwendung unterschiedlicher Laserwellenlängen großes Potenzial für die erfolgreiche Handhabung der Lumineszenz in der RS auf. In Kombination mit SERDS und/oder Photobleichen steigt die Wahrscheinlichkeit verwertbare Spektren für die Probencharakterisierung zu erhalten. / Raman spectroscopy (RS) is an analytical technique conveying material-specific information about a material’s molecular vibrations and crystal structure in succession of an optical excitation of the material. Due to the fact that mineralogical as well as biological material can be examined, RS is of special interest for space research. For instance, two Mars rovers (ExoMars and Mars 2020) will each carry along a Raman spectrometer in the year 2020, with the aim of detecting inter alia traces of extant or extinct extraterrestrial life. One of the biggest challenges in conventional RS is the characterization of strongly luminescent biological or mineralogical material; therefore, the dissertation at hand deals with the problem of luminescence in RS. For this purpose, the potential of five different Raman spectroscopic techniques for the handling of luminescence will be evaluated. These techniques include (i) the selection of different excitation wavelengths (325 nm, 532 nm, 785 nm and 1064 nm), which is based on the concept of the spectral separation of the luminescence signals as well as Raman signals. (ii) Photobleaching provides an alternative whereby the luminescence is suppressed by long exposure. (iii) A further method for the spectral separation of Raman photons as well as luminescence photons is provided by the anti-Stokes RS. (iv) The SERDS technique uses two slightly shifted excitation wavelengths. (v) Finally the examination of inelastic scattering and emission takes place in the time domain. The results of this dissertation show that there is no universal solution to overcome the problem of luminescence in RS. However, the usage of different excitation wavelengths offers great potential for handling luminescence in RS successfully. In combination with SERDS and/or photobleaching the probability to obtain exploitable spectra for sample characterization increases

In the year of 2017 in October a strange object with a hyperbolic trajectory was observed in our solar system. There were several hypotheses that scientists used to try to explain what kind of an object it was, but no one could, according to the scientific community as a whole, perpetuate any of these explanations as accepted consensus. One of the scientists who had an interest in this object is Professor Avi Loeb at Harvard University. He wrote and published a popular scientific book called “Extraterrestrial”. In this book Loeb make quite a few arguments that are backing up his hypothesis that this object is no ordinary asteroid or comet, it is in fact a relic from an advanced, technological, alien civilization which originates from a solar system far away from our own. Many people in the scientific community have not accepted these views by Loeb and one of them is Jonathan I. Katz who challenges Loeb’s hypothesis directly. Loeb on the other hand believes that the general resistance to his views is founded in the usual conservatism and that many scientists are afraid to advocate for something like this and risk their credibility and careers. / I oktober 2017 blev ett intressant objekt observerat i vårt solsystem. Det presenterades flera olika hypoteser av forskare som försökte förklara vad för typ av objekt detta var men ingen av dessa kunde ena hela den vetenskapliga gemenskapen och ingen konsensus kunde således uppnås. En av vetenskapsmännen som uppvisade ett intresse för detta objekt är en professor från Harvard University vid namn Avi Loeb.  Han skrev en populärvetenskaplig bok som heter ”Utomjordiskt”. I denna bok presenterar Loeb flera argument som har som syfte att stärka hypotesen att detta inte är någon vanlig asteroid eller komet, det är en kvarleva från en avancerad, teknologisk, utomjordisk civilisation, som härstammar från ett solsystem långt ifrån vårt eget. Den här ståndpunkten som Loeb uppvisar har blivit utmanad av flera fysiker inom vetenskapsvärlden inte minst av astrofysikern Jonathan. I Katz. Själv menar Loeb att detta generella motstånd beror på gammal konservatism hos flera vetenskapsmän som inte vågar sticka ut hakan och således riskera att skada anseende såväl som karriär.

This dissertation aims to develop an ethical system that can properly frame such questions as the morality of large-scale efforts to transform inanimate parts of nature, for example, proposals to terraform Mars. Such an ethics diverges from traditional approaches to ethics because it expands the class of entities regarded as morally considerable to include inanimate entities. I approach the task by building on the environmental ethical theory of Paul W. Taylor, as developed in his 1986 book Respect for Nature: A Theory of Environmental Ethics. I discuss various criticisms of Taylor and propose two extensions to his theory: an expansion of the scope of moral considerability to include all concrete material objects and the introduction of the concept of variable moral significance (the notion that all entities have inherent worth but some have more than others). Using Taylor’s modified and extended theory as a foundation, I develop something I call universal ethics. This is an ethical framework whose key elements are a fundamental ethical attitude of respect for the world and a principle of minimal harm. Universal ethics regards all concrete material entities, whether living or not, and whether natural or artefactual, as inherently valuable, and therefore as entitled to the respect of moral agents. I offer a defence of this ethical framework and discuss a number of practical applications, including criticism of proposals for the terraforming of Mars. I conclude that terraforming Mars or any other celestial body at this point in our history would be morally wrong. I also suggest that universal ethics provides an ethical foundation for efforts to protect Antarctica, and that it has implications for our relations to other inanimate parts of our world, including artefacts.

This dissertation aims to develop an ethical system that can properly frame such questions as the morality of large-scale efforts to transform inanimate parts of nature, for example, proposals to terraform Mars. Such an ethics diverges from traditional approaches to ethics because it expands the class of entities regarded as morally considerable to include inanimate entities. I approach the task by building on the environmental ethical theory of Paul W. Taylor, as developed in his 1986 book Respect for Nature: A Theory of Environmental Ethics. I discuss various criticisms of Taylor and propose two extensions to his theory: an expansion of the scope of moral considerability to include all concrete material objects and the introduction of the concept of variable moral significance (the notion that all entities have inherent worth but some have more than others). Using Taylor’s modified and extended theory as a foundation, I develop something I call universal ethics. This is an ethical framework whose key elements are a fundamental ethical attitude of respect for the world and a principle of minimal harm. Universal ethics regards all concrete material entities, whether living or not, and whether natural or artefactual, as inherently valuable, and therefore as entitled to the respect of moral agents. I offer a defence of this ethical framework and discuss a number of practical applications, including criticism of proposals for the terraforming of Mars. I conclude that terraforming Mars or any other celestial body at this point in our history would be morally wrong. I also suggest that universal ethics provides an ethical foundation for efforts to protect Antarctica, and that it has implications for our relations to other inanimate parts of our world, including artefacts.

This dissertation aims to develop an ethical system that can properly frame such questions as the morality of large-scale efforts to transform inanimate parts of nature, for example, proposals to terraform Mars. Such an ethics diverges from traditional approaches to ethics because it expands the class of entities regarded as morally considerable to include inanimate entities. I approach the task by building on the environmental ethical theory of Paul W. Taylor, as developed in his 1986 book Respect for Nature: A Theory of Environmental Ethics. I discuss various criticisms of Taylor and propose two extensions to his theory: an expansion of the scope of moral considerability to include all concrete material objects and the introduction of the concept of variable moral significance (the notion that all entities have inherent worth but some have more than others). Using Taylor’s modified and extended theory as a foundation, I develop something I call universal ethics. This is an ethical framework whose key elements are a fundamental ethical attitude of respect for the world and a principle of minimal harm. Universal ethics regards all concrete material entities, whether living or not, and whether natural or artefactual, as inherently valuable, and therefore as entitled to the respect of moral agents. I offer a defence of this ethical framework and discuss a number of practical applications, including criticism of proposals for the terraforming of Mars. I conclude that terraforming Mars or any other celestial body at this point in our history would be morally wrong. I also suggest that universal ethics provides an ethical foundation for efforts to protect Antarctica, and that it has implications for our relations to other inanimate parts of our world, including artefacts.