Large Angular Scale Polarization of the Cosmic Microwave Background and the Feasibility of its Detection

In addition to its spectrum and temperature anisotropy, the 2.7K Cosmic Microwave Background is also expected to exhibit a low level of polarization. The spatial power spectrum of the polarization can provide details about the formation of structure in the universe as well as its ionization history. Here we calculate the magnitude of the CMB polarization in various cosmological scenarios, with both an analytic and a numerical method. We then outline the fundemental challenges to measuring these signals and focus on two of them: achieving adequate sensitivity and removing contamination from foreground sources. We then describe the design of a ground based instrument (POLAR) that could detect polarization of the CMB at large angular scales in the new few years.Comment: 40 pages, 7 figures, accepted for publication in the Astrophysical Journa

Cars, capitalism and ecological crises: understanding systemic barriers to a sustainability transition in the German car industry

In the face of climate and ecological crises, it is vital that car use be reduced, while simultaneously shifting towards different powertrains and reducing the size, weight and energy demand of vehicles. This poses a challenge to the global car industry, as its business model historically centres on selling more and larger cars. In this context, the purpose of this paper is to examine the social-ecological limits of industrial restructuring in Germany. A narrative literature review through the lens of Marxian political economy sheds light on intertwined system-immanent barriers to achieving social and ecological sustainability at the sectoral level. Consequently, powertrain electrification is structured by technological dynamism, which fuels appropriation in the quest for metals and rare earths, with significant social and ecological disadvantages. This generates an impasse for the industry’s transition strategies. Understanding how capitalist tendencies generate interlaced and mutually re-enforcing barriers to achieving social-ecological sustainability is key to understanding why industrial transitions are insufficient from a social-ecological perspective

A spatially explicit life cycle inventory of the global textile chain

Background, aim, and scope: Life cycle analyses (LCA) approaches require adaptation to reflect the increasing delocalization of production to emerging countries. This work addresses this challenge by establishing a country-level, spatially explicit life cycle inventory (LCI). This study comprises three separate dimensions. The first dimension is spatial: processes and emissions are allocated to the country in which they take place and modeled to take into account local factors. Emerging economies China and India are the location of production, the consumption occurs in Germany, an Organisation for Economic Cooperation and Development country. The second dimension is the product level: we consider two distinct textile garments, a cotton T-shirt and a polyester jacket, in order to highlight potential differences in the production and use phases. The third dimension is the inventory composition: we track CO2, SO2, NO x , and particulates, four major atmospheric pollutants, as well as energy use. This third dimension enriches the analysis of the spatial differentiation (first dimension) and distinct products (second dimension). Materials and methods: We describe the textile production and use processes and define a functional unit for a garment. We then model important processes using a hierarchy of preferential data sources. We place special emphasis on the modeling of the principal local energy processes: electricity and transport in emerging countries. Results: The spatially explicit inventory is disaggregated by country of location of the emissions and analyzed according to the dimensions of the study: location, product, and pollutant. The inventory shows striking differences between the two products considered as well as between the different pollutants considered. For the T-shirt, over 70% of the energy use and CO2 emissions occur in the consuming country, whereas for the jacket, more than 70% occur in the producing country. This reversal of proportions is due to differences in the use phase of the garments. For SO2, in contrast, over two thirds of the emissions occur in the country of production for both T-shirt and jacket. The difference in emission patterns between CO2 and SO2 is due to local electricity processes, justifying our emphasis on local energy infrastructure. Discussion: The complexity of considering differences in location, product, and pollutant is rewarded by a much richer understanding of a global production-consumption chain. The inclusion of two different products in the LCI highlights the importance of the definition of a product's functional unit in the analysis and implications of results. Several use-phase scenarios demonstrate the importance of consumer behavior over equipment efficiency. The spatial emission patterns of the different pollutants allow us to understand the role of various energy infrastructure elements. The emission patterns furthermore inform the debate on the Environmental Kuznets Curve, which applies only to pollutants which can be easily filtered and does not take into account the effects of production displacement. We also discuss the appropriateness and limitations of applying the LCA methodology in a global context, especially in developing countries. Conclusions: Our spatial LCI method yields important insights in the quantity and pattern of emissions due to different product life cycle stages, dependent on the local technology, emphasizing the importance of consumer behavior. From a life cycle perspective, consumer education promoting air-drying and cool washing is more important than efficient appliances. Recommendations and perspectives: Spatial LCI with country-specific data is a promising method, necessary for the challenges of globalized production-consumption chains. We recommend inventory reporting of final energy forms, such as electricity, and modular LCA databases, which would allow the easy modification of underlying energy infrastructur

Your money or your life? The carbon-development paradox

The relationship between human health and well-being, energy use and carbon emissions is a foremost concern in sustainable development. If past advances in well-being have been accomplished only through increases in energy use, there may be significant trade-offs between achieving universal human development and mitigating climate change. We test the explanatory power of economic, dietary and modern energy factors in accounting for past improvements in life expectancy, using a simple novel method, functional dynamic decomposition. We elucidate the paradox that a strong correlation between emissions and human development at one point in time does not imply that their dynamics are coupled in the long term. Increases in primary energy and carbon emissions can account for only a quarter of improvements in life expectancy, but are closely tied to growth in income. Facing this carbon-development paradox requires prioritizing human well-being over economic growth

Progress towards high precision measurements on ultracold metastable hydrogen and trapping deuterium

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2004.Includes bibliographical references (leaves 128-136).(cont.) not achieve deuterium trapping through helium-surface cooling. It is proposed that buffer gas loading can be used to cryogenically cool and trap deuterium.Ultracold metastable trapped hydrogen can be used for precision measurements for comparison with QED calculations. In particular, Karshenboim and Ivanov [Eur. Phys. Jour. D 19, 13 (2002)] have proposed comparing the ground and first excited state hyperfine splittings of hydrogen as a high precision test of QED. An experiment to measure the 2S hyperfine splitting using a field-independent transition frequency in the 2S manifold of hydrogen is described. The relation between the transition frequency and the hyperfine splitting requires incorporating relativistic and bound state QED corrections to the electron and proton g-factors in the Breit-Rabi formula. Experimental methods for measuring the magnetic field of an ultracold hydrogen sample are developed for trap fields from 0 to 900 G. The temperature of the trapped sample at the field-independent point is a critical parameter, and is inferred from the IS - 2S lineshape. The detailed dependence of this lineshape on the trap geometry is examined. A search for the transition was undertaken, but no signal was observed. The systematics of the experiment are analyzed, and modifications for carrying out the experiment are proposed. In a separate study, the possibilities for trapping (never previously trapped) deuterium in the same cryogenic cell and magnetic trap used to trap hydrogen were investigated. Deuterium's behavior on a helium surface differs markedly from that of hydrogen due to its larger surface binding energy. We carried out a variety of studies of both hydrogen and deuterium during the trap-loading stage, working with both ⁴He and ³He surfaces. Introducing ³He in the cell decreases the surface binding energy of deuterium, and thus the rate of recombination on the cell walls; however, we couldby Julia K. Steinberger.Ph.D

Precision Timing of Two Anomalous X-Ray Pulsars

We report on long-term X-ray timing of two anomalous X-ray pulsars, 1RXS J170849.0-400910 and 1E 2259+586, using the Rossi X-ray Timing Explorer. In monthly observations made over 1.4 yr and 2.6 yr for the two pulsars, respectively, we have obtained phase-coherent timing solutions which imply that these objects have been rotating with great stability throughout the course of our observations. For 1RXS J170849.0-400910, we find a rotation frequency of 0.0909169331(5) Hz and frequency derivative -15.687(4) x 10^(-14) Hz/s, for epoch MJD 51215.931. For 1E 2259+586, we find a rotation frequency of 0.1432880613(2)Hz, and frequency derivative -1.0026(7) x 10^(-14) Hz/s, for epoch MJD 51195.583. RMS phase residuals from these simple models are only about 0.01 cycles for both sources. We show that the frequency derivative for 1E 2259+586 is inconsistent with that inferred from incoherent frequency observations made over the last 20 yr. Our observations are consistent with the magnetar hypothesis and make binary accretion scenarios appear unlikely.Comment: 12 pages including 3 figures. To appear in ApJ Letter

The climate change research that makes the front page: Is it fit to engage societal action?

By growing awareness for and interest in climate change, media coverage enlarges the window of opportunity by which research can engage individuals and collectives in climate actions. However, we question whether the climate change research that gets mediatized is fit for this challenge. From a survey of the 51,230 scientific articles published in 2020 on climate change, we show that the news media preferentially publicizes research outputs found in multidisciplinary journals and journals perceived as top-tier. An in-depth analysis of the content of the top-100 mediatized papers, in comparison to a random subset, reveals that news media showcases a narrow and limited facet of climate change knowledge (i.e., natural science and health). News media selectivity reduces climate change research to the role of a sentinel and whistleblower for the large-scale, observed, or end-of-century consequences of climate change for natural Earth system components. The social, economic, technological, and energy aspects of climate change are curtailed through mediatization, as well as local and short-term scales of processes and solutions. Reviewing the social psychological mechanisms that underlie behavioral change, we challenge the current criteria used to judge newsworthiness and argue that the consequent mediatization of climate change research fails to breed real society engagement in actions. A transformative agenda for the mediatization of climate change research implies aligning newsworthiness with news effectiveness, i.e., addressing the extent to which communication is effective in presenting research that is likely to produce behavioral change