New Worlds: Colonizing Planets, Moons and Beyond
Abstract
Terraforming is the process of modifying a planet, moon, or other body to a more habitable atmosphere, temperature, or ecology. The idea of terraforming or colonizing other planets has recently become a topic of intense scientific interest and public debate. Geoengineering and terraforming, at their core, have the same goal: to enhance or revive the ability of a specific environment to support human life, society, and industry. New Worlds: Colonizing Planets, Moons and Beyond examines extra-terrestrial colonization plans with a critical eye. The ten chapters of the book provide a detailed review of the demographic and economic reasons behind this space imperative, technical and ecological solutions to improve the settlement of our own planet, enhancements of our current space industry. The book also covers interesting topics such as the terraformation of Mars, the moon, and other planets like Venus, colonizing the outer solar system (and beyond), and the ethical considerations in favor of space expansion. This simple, yet informative treatise is an essential read for anyone interested in the subject of space colonization
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There are still many open questions regarding the nature of Uranus and Neptune, the outermost planets in the Solar System. In this review we summarize the current-knowledge about Uranus and Neptune with a focus on their composition and internal structure, formation including potential subsequent giant impacts, and thermal evolution. We present key open questions and discuss the uncertainty in the internal structures of the planets due to the possibility of non-adiabatic and inhomogeneous interiors. We also provide the reasoning for improved observational constraints on their fundamental physical parameters such as their gravitational and magnetic fields, rotation rates, and deep atmospheric composition and temperature. Only this way will we be able to improve our understating of these planetary objects, and the many similar-sized objects orbiting other stars.
This paper describes steps to be taken for terraforming planet Mars using today’s level of technology and knowledge. Terraforming as a process of creating an Earth-like or habitable environment is unique in sense that it has never done before. Detailed description and calculation of solar wind collection as a source of hydrogen has been laid out in the paper. Supply of big quantities of hydrogen using magnetic and electric lenses positioned on first Lagrange point between Sun and Mars has been described. Estimation of necessary investments based on commercial exploitation of solar wind and extraction of Helium-3 and other materials for commercial use has been estimated. Estimation of impact of hydrogen interaction with carbon dioxide creating water, methane and their impact as green-house gases will increase Mars’s average temperature. Interactions of hydrogen atoms with oxides in Martian soil will release water molecules in atmosphere. Effects of released energy and overall increase of temperature will melt undersoil frozen reserves of water and carbon dioxide. Mining of Martian minerals and their exploitation will enable building of future permanent human settlements on Mars.
Many studies have reported that the Arctic is greening; however, we lack an understanding of the detailed patterns and processes that are leading to this observed greening. The normalized difference vegetation index (NDVI) is used to quantify greening, which has had largely positive trends over the last few decades using low spatial resolution satellite imagery such as AVHRR or MODIS over the pan-Arctic region. However, substantial fine scale spatial heterogeneity in the Arctic makes this large-scale investigation hard to interpret in terms of vegetation and other environmental changes. Here we focus on one area of the northern Alaska Arctic using high spatial resolution (4 m) multispectral satellite imagery from DigitalGlobe™ to analyze the greening trend near Utqiaġvik (formerly known as Barrow), Alaska over 14 years from 2002 to 2016. We found that tundra vegetation has been greening (τ = 0.65, p = 0.01, NDVI increase of 0.01 yr-1) despite no overall change in vegetation community composition. The greening is most closely correlated to the number of thawing degree days (R2 = 0.77, F = 21.5, p < 0.001) which, increased in a similar linear trend over the 14-year study period (1.79 ± 0.50 days per year, p < 0.01, τ = -0.56). This suggests that in this Arctic ecosystem, greening is occurring due to a lengthening growing season that appears to stimulate plant productivity without any significant change in vegetation communities. We found that vegetation communities in wetter locations greened about twice as fast as those found in drier conditions supporting the hypothesis that these communities respond more strongly to warming. We suggest that in Arctic environments, vegetation productivity may continue to rise, particularly in wet areas.
The low temperatures1,2 and high ultraviolet radiation levels³ at the surface of Mars today currently preclude the survival of life anywhere except perhaps in limited subsurface niches⁴. Several ideas for making the Martian surface more habitable have been put forward5–8, but they all involve massive environmental modification that will be well beyond human capability for the foreseeable future⁹. Here, we present a new approach to this problem. We show that widespread regions of the surface of Mars could be made habitable to photosynthetic life in the future via a solid-state analogue to Earth’s atmospheric greenhouse effect. Specifically, we demonstrate via experiments and modelling that under Martian environmental conditions, a 2–3 cm-thick layer of silica aerogel will simultaneously transmit sufficient visible light for photosynthesis, block hazardous ultraviolet radiation and raise temperatures underneath it permanently to above the melting point of water, without the need for any internal heat source. Placing silica aerogel shields over sufficiently ice-rich regions of the Martian surface could therefore allow photosynthetic life to survive there with minimal subsequent intervention. This regional approach to making Mars habitable is much more achievable than global atmospheric modification. In addition, it can be developed systematically, starting from minimal resources, and can be further tested in extreme environments on Earth today.
Detection and monitoring land use/land cover (LULC) changes using historical multi-temporal remote sensing data is greatly important for providing an effective and robust assessment of the human-induced impacts on the environmental conditions. It is extremely recommended for LULC studies related to evaluating the sustainability of changing areas over time. The agricultural sector in Egypt is one of the crucial pillars of the national economy. The amount of traditional agricultural land (Old Lands) in the Nile Delta had a significant decline over the past few decades due to urban encroachment. Consequently, several land reclamation initiatives and policies have been adopted by the Egyptian government to expand agricultural land in desert areas (New Lands) adjacent to both fringes of the Nile delta. Tiba district is one of those newly reclaimed areas located in the western Nile Delta of Egypt with a total area of 125 km2. The primary objective of this article was to identify, monitor and quantify historical LULC changes in Tiba district using historical multi-temporal Landsat imageries for six different dates acquired from 1988 to 2018. The temporal and historical changes that occurred were identified using supervised maximum likelihood classification (MLC) approach. Three major LULC classes were distinguished and mapped: (1) Agricultural land; (2) barren land; and (3) urban land. In 1988, Tiba district was 100% barren land; however, during the 1990s, the governmental reclamation projects have led to significant changes in LULC. The produced LULC maps from performing the MLC demonstrated that Tiba district had experienced significant agricultural land expansion from 0% in 1988 to occupy 84% in 2018, whilst, barren land area has decreased from 100% in 1988 to occupy only 7% in 2018. This reflects the successful governmental initiatives for agricultural expansion in desert areas located in the western Nile Delta of Egypt.
Heat storage with a thermochemical reaction has the advantages of a high heat storage density and no heat loss compared to conventional methods such as the sensible and latent heat. This method is promising to use in a thermal energy network because it is an efficient solution which addresses the time mismatch problem with regard to heat production and consumption. In this paper, we investigated Magnesium oxide (MgO) with different additives as a thermochemical material (TCM) coupled with the effects of several additives in an effort to improve the structural strength and reaction rate and reduce the initiation time. As additives in an MgO composite, Bentonite, Magnesium sulfate (MgSO4), and Zeolite 13X were chosen. With a cyclic scheduling experimental setup for the heat charging and discharging of the MgO composites, Bentonite as an additive improved the structural strength, and Zeolite 13X enhanced the reaction rate and led to faster reactions compared to only MgO as a TCM. With MgSO4 as an additive, however, the TCM composite showed a high reactivity during the a few cycles, and then rapidly became inactive due to byproducts side reaction. The results indicated that Bentonite and Zeolite additives, in an MgO composite, as a TCM can improve the mechanical strength and chemical reaction, optimum ratio is necessary to compromise promoting the thermochemical reaction.
Peatlands represent large terrestrial carbon banks. Given that most peat accumulates in boreal regions, where low temperatures and water saturation preserve organic matter, the existence of peat in (sub)tropical regions remains enigmatic. Here we examined peat and plant chemistry across a latitudinal transect from the Arctic to the tropics. Near-surface low-latitude peat has lower carbohydrate and greater aromatic content than near-surface high-latitude peat, creating a reduced oxidation state and resulting recalcitrance. This recalcitrance allows peat to persist in the (sub)tropics despite warm temperatures. Because we observed similar declines in carbohydrate content with depth in high-latitude peat, our data explain recent field-scale deep peat warming experiments in which catotelm (deeper) peat remained stable despite temperature increases up to 9 °C. We suggest that high-latitude deep peat reservoirs may be stabilized in the face of climate change by their ultimately lower carbohydrate and higher aromatic composition, similar to tropical peats.
All known life forms trace back to a last universal common ancestor (LUCA) that witnessed the onset of Darwinian evolution. One can ask questions about LUCA in various ways, the most common way being to look for traits that are common to all cells, like ribosomes or the genetic code. With the availability of genomes, we can, however, also ask what genes are ancient by virtue of their phylogeny rather than by virtue of being universal. That approach, undertaken recently, leads to a different view of LUCA than we have had in the past, one that fits well with the harsh geochemical setting of early Earth and resembles the biology of prokaryotes that today inhabit the Earth's crust.
We review the geochemical observations of water, D / H and volatile element abundances of the inner Solar System bodies, Mercury, Venus, the Moon, and Mars. We focus primarily on the inventories of water in these bodies, but also consider other volatiles when they can inform us about water. For Mercury, we have no data for internal water, but the reducing nature of the surface of Mercury would suggest that some hydrogen may be retained in its core. We evaluate the current knowledge and understanding of venusian water and volatiles and conclude that the venusian mantle was likely endowed with as much water as Earth of which it retains a small but non-negligible fraction. Estimates of the abundance of the Moon’s internal water vary from Earth-like to one to two orders of magnitude more depleted. Cl, K, and Zn isotope anomalies for lunar samples argue that the giant impact left a unique geochemical fingerprint on the Moon, but not the Earth. For Mars, an early magma ocean likely generated a thick crust; this combined with a lack of crustal recycling mechanisms would have led to early isolation of the Martian mantle from later delivery of water and volatiles from surface reservoirs or late accretion. The abundance estimates of Martian mantle water are similar to those of the terrestrial mantle, suggesting some similarities in the water and volatile inventories for the terrestrial planets and the Moon.
The Effects of Hypergravity and Radiation Exposure on Plants and their Terrestrial and Space Applications
Marlise A dos Santos, Ph.D.1, Beatriz A de Souza1, Natalia Guimarães1, Felipe C Escobal1, Patrícia B. Lazzarotto1, Philippe A Souvestre2, Thais Russomano3.
1Microgravity Centre- PUCRS, Av Ipiranga, 6681, Partenon - Porto Alegre, 90619-900 / RS/ Brazil, marlise.santos@pucrs.br
2 NeuroKinetics Health Services, Inc., Hycroft Medical Centre, 60-3195 Granville St., Vancouver, BC, V6H 3K2, Canada, pas@neurokinetics.com
3 Centre of Human and Aerospace Physiological Sciences, School of Basic and Medical Biosciences, Faculty of Life Sciences and Medicine, King’s College London, Shepherd's House, Guy's Campus, London SE1 1UL, thais.russomano@kcl.ac.uk
Introduction: The Bellagio II Summit discussed several aspects related to space nutrition, space pharmacy and the influence of the space environment on plants and their compounds. Plant germination and growth are influenced by innumerous environmental factors, such as the level of gravity and type of radiation. Since several plants have nutritive and medicinal value, the importance of their cultivation and consumption during space missions are unquestionable. Studies have demonstrated that simulated hypergravity through centrifuge exposure increases the number of seed germination, accelerates plant growth and the modifies metabolites produced by some plants. The radiation of space, either in Low Earth Orbit or in deep space, can also positively impact on plant growth and metabolite production.
Methods: The effects of different levels of gravitational fields and types of radiation on plant germination and development were reviewed for application in space missions and food and pharmaceutical industries on Earth.
Results: Faster germination and increased growth of Rocket plant seeds, as well as higher rates of germination of carrot seeds were observed when subjected to intermittent exposure at +7Gz. The scientific literature shows that using UV-C radiation (non-ionizing radiation) on arugula increased its production of antioxidant and polyphenols compounds, and shortened strawberry maturation by 4 to 8 days, without affecting the average weight of the fruit. Gamma (ionizing) radiation, however, reduced the average height of fava beans, but did not affect germination. It can also be used to disinfect vegetables.
Discussion: This paper reviewed the literature related to the effects of hypergravity conditions, as well as different types of radiation exposure on the plant life cycle and production of their compounds. The findings reviewed suggest that several plants present faster rates of germination and growth under hypergravity conditions. This may motivate the cultivation of such plants and vegetables using this method, not only on Earth, but also in more extreme environments, such as those found on space stations and extra-terrestrial bases. Studies conducted worldwide have demonstrated the potential advantages of applying radiation on plants. Hypergravity and radiation exposure, therefore, might be useful for terrestrial applications, especially in food production and medication development.
Gravity is the only component of Earth environment that remained constant throughout the entire process of biological evolution. However, it is still unclear how gravity affects plant growth and development. In this study, an in vitro cell culture of Arabidopsis thaliana was exposed to different altered gravity conditions, namely simulated reduced gravity (simulated microgravity, simulated Mars gravity) and hypergravity (2g), to study changes in cell proliferation, cell growth, and epigenetics. The effects after 3, 14, and 24-hours of exposure were evaluated. The most relevant alterations were found in the 24-hour treatment, being more significant for simulated reduced gravity than hypergravity. Cell proliferation and growth were uncoupled under simulated reduced gravity, similarly, as found in meristematic cells from seedlings grown in real or simulated microgravity. The distribution of cell cycle phases was changed, as well as the levels and gene transcription of the tested cell cycle regulators. Ribosome biogenesis was decreased, according to levels and gene transcription of nucleolar proteins and the number of inactive nucleoli. Furthermore, we found alterations in the epigenetic modifications of chromatin. These results show that altered gravity effects include a serious disturbance of cell proliferation and growth, which are cellular functions essential for normal plant development.
The ACUUS, the Associated research Centers for the Urban Underground Space, was established in Montreal in 1997 to promote partnership amongst all actors involved in the planning, design, construction, management and research on urban underground space. To explain how ACUUS has become an international organization over the years, and recognized by UN-Habitat, the evolution of global attention on underground space since the 19th century, with the gradual arrival of national and international organizations dedicated to the underground. Based on personal experience as a municipal planner, ways in which urban underground space should be planned and managed are described. The underground should be a place for people as much as for tunnels and public utilities. Montreal Underground City, one of the largest of its kind in the world, is used to demonstrate how, since 1962, underground use can evolve and the sub-surface can be “humanized”. Some global trends are described, and challenges that need to be overcome in order to “populate” the underground, are also highlighted.
The 21st century will probably be the century of urban areas and especially megacities. Megacities are continuously growing in size and numbers, they are major economic and political hubs and every event or decision that affects these areas has significant repercussions for the rest of the planet. These large agglomerations have soaring problems that challenge their sustainability goals and their future in general. The development of the urban underground space can offer efficient, long-term and environmental friendly solutions to these problems and keep megacities in the sustainability path. The present paper describes the sustainability problems of modern cities and attempts to outline the new challenges in future underground utilization. The paper also focuses on the people who work in the underground space and analyzes the social and psychological results. Finally, since, contrary to common belief, the most visited places in the world are underground, several issues regarding design, aesthetics and human friendly underground spaces are discussed along with the pioneer role of ACUUS in underground development.
Gravity deeply influences numerous biological events in living organisms. Variations in gravity values induce adaptive reactions that have been shown to play important roles, for instance in cell survival, growth, and spatial organization. In this paper, we summarize effects of gravity values higher than that one experienced by cells and tissues on Earth, i.e., hypergravity, with particular attention to the nervous and the musculoskeletal systems. Besides the biological consequences that hypergravity induces in the living matter, we will discuss the possibility of exploiting this augmented force in tissue engineering and regenerative medicine, and thus hypergravity significance as a new therapeutic approach both in vitro and in vivo.
What role will Mercury play once Humanity becomes a space faring race and establishes a civilization that spans the solar system? It could become the industrial center of such a civilization because of its light gravity, material resources, and plentiful solar energy that can be concentrated to achieve very high temperatures or converted into almost unlimited quantities of electrical energy. One can envision robotic factories turning out space ships and components needed to assemble vast space settlements.
Restinga formations grow on sandy spits of coastal plains, an environment whose conditions limit the growth and development of vegetal species. Studies on restinga gradients are good examples of how plants acclimate to restrictive environments. This work compares three woody species co-occurring in four vegetations of a restinga from Southern Brazil. It pinpoints morpho-anatomical attributes that favor the survival of species faced with spatial variability of soil and light conditions. Results indicate that they respond differently to environmental variables on different scales. The plastic response of morphological attributes is more marked than that of anatomical ones. Varronia curassavica and Dodonaea viscosa showed more xeromorphic features on the more stressful restinga formations while Symphyopappus casarettoi varied between xerophyte to mesophyte forms along the gradient. Individual height, fresh and dry leaf masses, leaf area, specific leaf mass and area, leaf density, and water content are particularly noteworthy. These responses are strategies allowing the studied species to survive in restinga environment with highly variable soil nutrient, water availability, and light conditions. The environmental conditions are important features that modulate de plant morphology along the gradient.
This paper presents the results from the Phase 1 NASA Innovative and Advanced Concepts (NIAC) investigation for the Robotic Asteroid Prospector (RAP). The project investigated several aspects of developing an asteroid mining mission. It conceived a Space Infrastructure Framework that would create a demand for in space-produced resources. The resources identified as potentially feasible in the near-term were water and platinum group metals. The project's mission design stages spacecraft from an Earth Moon Lagrange (EML) point and returns them to an EML. The spacecraft's distinguishing design feature is its solar thermal propulsion system (STP) that can provide for three functions: propulsive thrust, process heat for mining and mineral processing, and electricity. The preferred propellant is water since this would allow the spacecraft to refuel at an asteroid for its return voyage to cislunar space thus reducing the mass that must be staged out of the EML point. This paper focuses on mining and processing technologies. Nomenclature ARM = asteroid retrieval mission ARProbe = Asteroid Reconnaissance Probe EML = Earth-Moon Lagrange libration point GNC = guidance, navigation, and control GCR = galactic cosmic rays ISRU = in situ resource utilization LH2 = liquid hydrogen LOX = liquid oxygen PGM = platinum group metals REE = rare earth elements RAP = Robotic Asteroid Prospector RTG = radio-thermal generator TRL = NASA technology readiness level
Underground infrastructures and buildings are new urban forms. This paper gives an overview of the strategic framework for developing and managing urban underground space (UUS) development, which represents a rational iterative process going through steps of 'criteria framing', 'data building', 'city-scale zoning', 'project-scale evaluating', 'decision analyzing', and 'policy making'. Each step will be illustrated in detail, while we will mainly focus on project evaluation by introducing new urban economic indicators, and on decision analysis by using decision criteria in scenario analysis. Optimization of urban underground space use has to take into account social-economic demand and supply capacity of geo-space resources. Urban development land can be classified based on a zoning system mapping subsurface integrated quality, which is an indicator combining engineering constructability and development value of below-ground space. Based on this macro-zoning of UUS at a city scale, land parcels of high potential can be selected or stock-taken for short-term development, while special protection areas can be reserved for valuable geo-resources protection for long-term use. An economic model is developed to perform micro-analysis for project scenario evaluation. Two economic indicators ('underground development rate' and 'underground premium') will help to integrate underground options into real-estate project appraisal. The decision criteria will take into account direct and indirect costs generated along the project life cycle, developer gains and social benefits for the whole community, opportunities for synergetic resources exploitation (e.g. geothermal energy use), and risks induced by sectorial development patterns (e.g. groundwater damage). These main criteria of cost, benefit, opportunity and risk are useful for decision-makers to promote urban subsurface projects in a sustainable way. At the end, a multi-criteria decision-making process with performance indicators will be demonstrated, designed to guide strategic development and policy making. The improvement in policy making will further change the 'criteria framing' for successful underground development practices, enabling a continuous improvement cycle for underground space management in urban areas. Copyright © 2013 by The Society for Rock Mechanics & Engineering Geology.
Chronic periodontal diseases, which mainly include gingivitis and periodontitis, have been described as the inflammation of the supporting tissues of the teeth. The main cause of periodontal diseases is the accumulation of the microbial dental plaque. If dental plaque is not eliminated by mechanical or chemical plaque control methods, mineralized dental plaque (calculus) occurs. The mineralization process and mechanisms of the dental calculus formation are similar to that of other pathologic calcifications. The presence of a certain type of microorganism is discovered in various pathological calcifications, such as kidney stones and arterial plaques. This microorganism is the nanobacterium. Thus, it may be considered as a potential risk factor for the chronic periodontal diseases. Nanobacterium is one of the most controversial issues in today's biological studies. Nanobacteria, as the smallest known self-replicating bacteria, are classified as Gram-negative organisms. Although their growth is slow, they grow best under aerobic conditions. Their doubling time is about three days with the metabolic rate, which is 10,000 times slower than that in Escherichia coli. Nanobacteria are also resistant to heat and various conditions that would normally kill other bacteria. Present data suggest that nanobacteria are only killed by ethylenediaminetetraacetic acid and tetracycline. The aim of this paper was to perform a narrative review of publications on nanobacteria since 1998 and highlight their hypothesized relationship with the periodontal disease.
Posttranscriptional modifications greatly enhance the chemical information of RNA molecules, contributing to explain the diversity of their structures and functions. A significant fraction of RNA experimental structures available to date present modified nucleobases, with half of them being involved in H-bonding interactions with other bases, i.e. 'modified base pairs'. Herein we present a systematic investigation of modified base pairs, in the context of experimental RNA structures. To this end, we first compiled an atlas of experimentally observed modified base pairs, for which we recorded occurrences and structural context. Then, for each base pair, we selected a representative for subsequent quantum mechanics calculations, to find out its optimal geometry and interaction energy. Our structural analyses show that most of the modified base pairs are non Watson-Crick like and are involved in RNA tertiary structure motifs. In addition, quantum mechanics calculations quantify and provide a rationale for the impact of the different modifications on the geometry and stability of the base pairs they participate in.
© The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.
Because the Holy Land occupies a land bridge between the two great centers of early Near Eastem cul-ture—Egypt and Mesopotamia— the Holy Land and its social évolu-tion have usually been linked to thèse core areas of ancient civilization. Récent excavations in Israel's northem Negev Désert at the late fifth to early fourth millennium BC settlement of Shiqmim provide insights into the growth and décline of the earliest agro-pastoral settlement System in the Beersheva Valley. The new data point to a local growth process with little direct influence from the outside world. Numerous radiocarbon détermina-tions, extensive Systems of subterranean rooms in the lowest occupation levels, and a planned open-air settlement in the latest stratum, challenge théories conceming the developmental history of human societies in this part of the Near East. Analyses of fauna and craft specialization in métal add insi^ts into the émergence of the Mediter-ranean economy and social complexity in the ancient Levant. Figure 1. Circular foundations of a multiple secondary burial tomb, Shiqmim cemetery 111. THOMAS LUDOVISE T HE I^ATE FIFTH TO EARLY FOURTH M1LLENNL\C marked a pcri-od of technological and social change along the eastern Mediterranean seaboard (Israël and Jordan). Most signih-cant, human population increased dramatically, formai sanctuaries and cemeteries were established, metallurgy and craft specialization grew, distinct régional cultures developed, and settlement centers or central places that coordinated social, économie, and religions activities emerged.« s Archaeologists are divided in their interprétation of thèse changes. Some scholars think thèse developments reflect the émergence of new social formations in the lower Jordan Valley and northem Negev Désert. Based on ethnographie and ethnohistoric data, anthropological archaeologists such as T. E. Levy and A. Holl refer to thèse vibrant hierarchically organized societies as "chiefdom" organizations.i^-^^ Others, such as I. Gilead,!'' reconstmct the Levant as "provincial" and hnd little évidence for the émergence of social complexity during the Chalcolithic. According to that interprétation, culture change in the Levant during this period was minimal and resulted from readjustments to larger-scale changes in the ancient Near Eastem cultural centers. i^-^o Two outstanding features of the Chalcolithic period in Palestine are the enigmatic "subterranean villages" along the wadi banks of the Beersheva Valley, hrst discovered by J. Perrot,**5 48 a^id a sophisticated métal industry in the Judean and Negev Déserts unparalleled at this time in the Near East.Opinions differ as to the significance of thèse developments for the évolution of society in the Negev and Judean Déserts. Excavations at Shiqmim, a large Chalcolithic settlement center in the Beersheva Valley, provide the detailed stratigraphie and material culture data necessary to examine thèse problems anew.
Undersea living in the science community has effectively risen and fallen within the last half century. The paradigm of residing on the seafloor within a fixed, permanent structure, while body tissues are saturated with inert breathing gasses, provides for extended-duration
excursions from such a structure, although limits geographical productivity to within reasonable proximity of the habitat structure itself. Saturation diving exploration with science motives provided an exciting opportunity during the 1960s and 1970s, with timing lending itself well to providing
a sea-to-space analog for human residence in a remote and confined space, as the space race was underway. With limited saturation diving for science occurring presently, today’s marine science paradigm is trending toward advanced autonomous diving technologies and techniques, including
mixed-gas use, rebreathers, and staged decompression. These emerging technologies afford an enhanced “commodity-style” approach to exploration, in which diving scientists can travel to any remote locale and spend longer durations underwater than they can with the previous and more
common paradigm of lightweight, travel-friendly, conventional open-circuit scuba (using air as the breathing medium). Amiss in the new paradigm is the practical extension of depth. This is well within reach with the use of emerging technologies; however, end-users are often dissuaded from
the incurrence of lengthy decompression (exposure to the marine environment during what is effectively an extended idle time) that is required when scientists return from relatively short working periods at extended depths. In an effort to address these issues, we describe here the development
and experimental deployment of a new class of portable inflatable underwater habitats that provide for rapid deployments, free from surface support augmentation requirements typical of the existing alternatives for lengthy decompression dives. In the context of vastly expanding the commodity-style
diving requirements of today’s marine scientist and engineers, particularly in terms of increased depth and duration, we also discuss the further research and development applications that these habitats make possible.
The gravity and topography of Venus obtained from observations of the Magellan mission, as well as the gravity and topography from our numerical mantle convection model, are discussed in this paper. We used the hypothesis that the geoid of degrees 2-40 is produced by sublithospheric mantle density anomalies that are associated with dynamical process within the mantle. We obtained the model dynamical admittance (the geoid topography ratio based on a convection model) by a numerical simulation of the Venusian mantle convection, and used it to correct the dynamical effect in the calculation of crustal thickness. After deducting the dynamical effect, the thickness of the Venusian crust is presented. The results show that the gravity and topography are strongly correlated with the Venusian mantle convection and the Venusian crust has a significant influence on the topography. The Venusian crustal thickness varies from 28 to 70 km. Ishtar Terra, and Ovda Regio and Thetis Regio in western Aphrodite Terra have the highest crustal thickness (larger than 50 km). The high topography of these areas is thought to be supported by crustal compensation and our results are consistent with the hypothesis that these areas are remnants of ancient continents. The crustal thickness in the Beta, Themis, Dione, Eistla, Bell, and Lada regiones is thin and shows less correlation with the topography, especially in the Atla and Imdr regiones in the eastern part of Aphrodite Terra. This is consistent with the hypothesis that these highlands are mainly supported by mantle plumes. Compared with the crustal thickness calculated with the dynamical effect, our results are more consistent with the crust evolution and internal dynamical process of Venus.
Climatic changes over the last 50 years resulted in a decrease of permafrost extent, an increase of permafrost temperature, and deepening of the active layer in numerous locations across the Arctic and High Mountainous environments. Permafrost degradation poses serious impacts ranging from local changes in topographic and hydrologic conditions, impacts on infrastructure and sustainability of northern communities, changes to vegetation and wildlife dynamics, and to global impacts on climate system. Hazards associated with permafrost degradation are exacerbated in areas of human activities, especially in large settlements with developed infrastructure in the Arctic. Unlike smaller communities, which have higher mobility, large population centers have to build in situ adaptive capacity to face environmental changes. Permafrost degradation can have severe socioeconomic consequences as most of the existing infrastructure will require expensive engineering solutions to maintain economic activities on permafrost.
Planetary Crusts explains how and why solid planets and satellites develop crusts. Extensively referenced and annotated, it presents a geochemical and geological survey of the crusts of the Moon, Mercury, Venus, Earth and Mars, the asteroid Vesta, and several satellites like Io, Europa, Ganymede, Titan and Callisto. After describing the nature and formation of solar system bodies, the book presents a comparative investigation of different planetary crusts and discusses many crustal controversies. The authors propose the theory of stochastic processes dominating crustal development, and debate the possibility of Earth-like planets existing elsewhere in the cosmos. Written by two leading authorities on the subject, this book presents an extensive survey of the scientific problems of crustal development, and is a key reference for researchers and students in geology, geochemistry, planetary science, astrobiology and astronomy.
We are fascinated by the seemingly impossible places in which organisms can live. There are frogs that freeze solid, worms that dry out and bacteria that survive temperatures over 100˚C. What seems extreme to us is, however, not extreme to these organisms. In this captivating account, the reader is taken on a tour of extreme environments, and shown the remarkable abilities of organisms to survive a range of extreme conditions, such as high and low temperatures and desiccation. This book considers how organisms survive major stresses and what extreme organisms can tell us about the origin of life and the possibilities of extraterrestrial life. These organisms have an extreme biology, which involves many aspects of their physiology, ecology and evolution.
We revisit the idea of ‘terraforming’ Mars — changing its environment to be more Earth-like in a way that would allow terrestrial life (possibly including humans) to survive without the need for life-support systems — in the context of what we know about Mars today. We want to answer the question of whether it is possible to mobilize gases present on Mars today in non-atmospheric reservoirs by emplacing them into the atmosphere, and increase the pressure and temperature so that plants or humans could survive at the surface. We ask whether this can be achieved considering realistic estimates of available volatiles, without the use of new technology that is well beyond today’s capability. Recent observations have been made of the loss of Mars’s atmosphere to space by the Mars Atmosphere and Volatile Evolution Mission probe and the Mars Express spacecraft, along with analyses of the abundance of carbon-bearing minerals and the occurrence of CO2 in polar ice from the Mars Reconnaissance Orbiter and the Mars Odyssey spacecraft. These results suggest that there is not enough CO2 remaining on Mars to provide significant greenhouse warming were the gas to be emplaced into the atmosphere; in addition, most of the CO2 gas in these reservoirs is not accessible and thus cannot be readily mobilized. As a result, we conclude that terraforming Mars is not possible using present-day technology.
Crustal thickness is a crucial geophysical parameter in understanding the geology and geochemistry of terrestrial planets. Recent development of mathematical techniques suggests that previous studies based on assumptions of isostasy overestimated crustal thickness on some of the solid bodies of the solar system, leading to a need to revisit those analyses. Here, I apply these techniques to Mercury. Using MESSENGER-derived elemental abundances, I calculate a map of grain density (average 2974 ± 89 kg/m³) which shows that Pratt isostasy is unlikely to be a major compensation mechanism of Mercury's topography. Assuming Airy isostasy, I find the best fit value for Mercury's mean crustal thickness is 26 ± 11 km, 25% lower than the most recently reported and previously thinnest number. Several geological implications follow from this relatively low value for crustal thickness, including showing that the largest impacts very likely excavated mantle material onto Mercury's surface. The new results also show that Mercury and the Moon have a similar proportion of their rocky silicates composing their crusts, and thus Mercury is not uniquely efficient at crustal production amongst terrestrial bodies. Higher resolution topography and gravity data, especially for the southern hemisphere, will be necessary to refine Mercury's crustal parameters further.
The Earth's deep interior contains significant reservoirs of volatiles such as H, C, and N. Due to the incompatible nature of these volatile species, it has been difficult to reconcile their storage in the residual mantle immediately following crystallization of the terrestrial magma ocean (MO). As the magma ocean freezes, it is commonly assumed, very small amounts of melt is retained in the residual mantle, limiting the trapped volatile concentration in the primordial mantle. In this article, we show that inefficient melt drainage out of the freezing front can retain large amounts of volatiles hosted in the trapped melt in the residual mantle while creating a thick early atmosphere. Using a two-phase flow model, we demonstrate that compaction within the moving freezing front is inefficient over time scales characteristic of magma ocean solidification. We employ a scaling relation between the trapped melt fraction, the rate of compaction, and the rate of freezing in our magma ocean evolution model. For cosmochemically plausible fractions of volatiles delivered during the later stages of accretion, our calculations suggest that up to 77% of total H2O and 12% of CO2 could have been trapped in the mantle during magma ocean crystallization. The assumption of a constant trapped melt fraction underestimates the mass of volatiles in the residual mantle by more than an order of magnitude.
We measured the mean plane of the Kuiper belt as a function of semi-major axis. For the classical Kuiper belt as a whole (the non-resonant objects in the semi-major axis range 42-48 au), we find a mean plane of inclination and longitude of ascending node (in the J2000 ecliptic-equinox coordinate system), in accord with theoretical expectations of the secular effects of the known planets. With finer semi-major axis bins, we see evidence for the expected warp of the mean plane near semi-major axes 40-42 au, owed to the nodal secular resonance. For the more distant Kuiper belt objects of semi-major axes in the range 50-80 au, the expected mean plane is close to the invariable plane of the solar system, but the measured mean plane deviates greatly from this: it has inclination and longitude of ascending node . We estimate this deviation from the expected mean plane to be statistically significant at the confidence level. We discuss several possible explanations for this deviation, including the possibility that a relatively close-in, low-mass unseen planet in the outer solar system is responsible for the warping.
Carbon nanotubes (CNTs), graphene (GRA), and their derivatives are promising materials for a wide range of applications such as pollutant removal, enzyme immobilization, bioimaging, biosensors, and drug delivery and are rapidly increasing in use and increasingly mass produced. The biodegradation of carbon nanomaterials by microbes and enzymes is now of great importance for both reducing their toxicity to living organisms and removing them from the environment. Here we review recent progress in the biodegradation field from the point of view of the primary microbes and enzymes that can degrade these nanomaterials, along with experimental and molecular simulation methods for the exploration of nanomaterial degradation. Further efforts should primarily aim toward expanding the repertoire of microbes and enzymes and exploring optimal conditions for the degradation of nanomaterials.
The weird quantum phenomenon of entanglement could produce shortcuts between distant black holes
Recent analyses have shown that distant orbits within the scattered disk population of the Kuiper Belt exhibit an unexpected clustering in their respective arguments of perihelion. While several hypotheses have been put forward to explain this alignment, to date, a theoretical model that can successfully account for the observations remains elusive. In this work we show that the orbits of distant Kuiper Belt objects (KBOs) cluster not only in argument of perihelion, but also in physical space. We demonstrate that the perihelion positions and orbital planes of the objects are tightly confined and that such a clustering has only a probability of 0.007% to be due to chance, thus requiring a dynamical origin. We find that the observed orbital alignment can be maintained by a distant eccentric planet with mass 10 m⊕ whose orbit lies in approximately the same plane as those of the distant KBOs, but whose perihelion is 180° away from the perihelia of the minor bodies. In addition to accounting for the observed orbital alignment, the existence of such a planet naturally explains the presence of high-perihelion Sedna-like objects, as well as the known collection of high semimajor axis objects with inclinations between 60° and 150° whose origin was previously unclear. Continued analysis of both distant and highly inclined outer solar system objects provides the opportunity for testing our hypothesis as well as further constraining the orbital elements and mass of the distant planet.
Understanding the evolution of eukaryotic cellular complexity is one of the grand challenges of modern biology. It has now been firmly established that mitochondria and plastids, the classical membrane-bound organelles of eukaryotic cells, evolved from bacteria by endosymbiosis. In the case of mitochondria, evidence points very clearly to an endosymbiont of α-proteobacterial ancestry. The precise nature of the host cell that partnered with this endosymbiont is, however, very much an open question. And while the host for the cyanobacterial progenitor of the plastid was undoubtedly a fully-fledged eukaryote, how - and how often - plastids moved from one eukaryote to another during algal diversification is vigorously debated. In this article I frame modern views on endosymbiotic theory in a historical context, highlighting the transformative role DNA sequencing played in solving early problems in eukaryotic cell evolution, and posing key unanswered questions emerging from the age of comparative genomics.
Nowadays, biologically oxidizing graphitic materials is of great importance for practical applications as an eco-friendly and low-cost method. In this work, a bacterial strain is isolated from the contaminated soil in graphite mine and its ability to oxidize graphite, graphene oxide (GO) and reduced graphene oxide (RGO) is confirmed. After being cultivated with bacteria, graphite is inhomogeneously oxidized, and moreover oxidized sheets exfoliated from graphite are detected in the medium. RGO shows higher oxidation degree compared to graphite owing to more original defects, while GO breaks into small pieces and becomes holey. Both the holes in GO and exfoliated sheets from graphite caused by bacteria have the size below 1 μm, in agreement with the size of bacterial cells. Besides, preliminary mechanism of the bacterial oxidation is explored, suggesting that the contact between bacrerial cells and materials promotes the oxidation of graphitic materials. The ability of naphthalene-degrading bacteria to oxidize and degrade the graphitic materials shows the prospect in producing GO in eco-friendly way and degrading carbon nano-materials in environment.
This paper critically reviews the state of the art of an approach to supply energy to earth from space mirrors that would be placed in orbit with angle control to reflect solar radiation to specific sites on earth for illumination, and also presents our (i) optical and mechanical tests to examine the property changes at a cryogenic temperature of thin film mirror that we manufactured, (ii) economic analysis related to several applications, and (iii) leading issues that must be taken into account in the sustainability analysis of the concept. The space mirrors were proposed to be of the order of a square kilometer or more each, planned to be made of thin plastic reflective films, which are launched to some optimal orbit around the Earth. One could, for example, thereby provide night or emergency illumination to cities and other locations, or illuminate agricultural production areas to lengthen the growing season, or to illuminate photovoltaic or thermal collectors on earth for producing electricity or heat. Proposals were also made for using such mirrors for weather modification, and we added here the possibility of using the space mirrors for shading the earth to reduce global warming. Experiments with space mirrors were conducted in the past by the former Soviet Union. Without (yet) consideration of environmental and social impact externalities, our economic analysis agrees with past studies that if transportation costs to mirror orbit are reduced to a few hundred $/kg, as planned, the use of orbiting space mirrors for providing energy to earth is an investment with a good rate of return and a cost effective alternative to other power sources. This energy concept is very appealing relative to other options for addressing the severe energy and global warming problems that we face, and deserves much and urgent R&D attention.
Quicklime (CaO) was added to a single sample of dewatered biosolids at rates of 5, 15, 20, 25, 30, 40, and 50% by weight (based on wet weight of the dewatered biosolids) in the laboratory. Temperature rise and water loss were monitored to determine caloric energy expended in heating and evaporation, and these values were compared to heat generation. The limed biosolids were analyzed by x-ray diffraction and thermal gravimetric analysis to determine the lime species present, and the pH rise when added to selected soils. Effects of lime dose on biosolids physical properties were examined by measuring selected physical characteristics of the limed products. Addition of CaO to dewatered biosolids produces heat through the exothermic conversion of CaO to hydrated lime [Ca(OH) 2], with only small amounts of heat produced from the exothermic reaction of carbon dioxide (CO 2) with Ca(OH) 2 to form calcium carbonate (CaCO 3). All heat produced was dissipated during heating of the biosolids and evaporation of water. Because of the predominance of Ca(OH) 2 in the timed biosolids, care should be taken in using these materials as liming agents and soil amendments because of the very high initial soil pHs (greater than pH 12) that can persist for weeks or more. Increasing lime dose improved the density and water-holding capacity of biosolids and improved their physical consistency.