The Comparative Exploration of the Ice Giant Planets with Twin Spacecraft: Unveiling the History of our Solar System

In the course of the selection of the scientific themes for the second and third L-class missions of the Cosmic Vision 2015-2025 program of the European Space Agency, the exploration of the ice giant planets Uranus and Neptune was defined "a timely milestone, fully appropriate for an L class mission". Among the proposed scientific themes, we presented the scientific case of exploring both planets and their satellites in the framework of a single L-class mission and proposed a mission scenario that could allow to achieve this result. In this work we present an updated and more complete discussion of the scientific rationale and of the mission concept for a comparative exploration of the ice giant planets Uranus and Neptune and of their satellite systems with twin spacecraft. The first goal of comparatively studying these two similar yet extremely different systems is to shed new light on the ancient past of the Solar System and on the processes that shaped its formation and evolution. This, in turn, would reveal whether the Solar System and the very diverse extrasolar systems discovered so far all share a common origin or if different environments and mechanisms were responsible for their formation. A space mission to the ice giants would also open up the possibility to use Uranus and Neptune as templates in the study of one of the most abundant type of extrasolar planets in the galaxy. Finally, such a mission would allow a detailed study of the interplanetary and gravitational environments at a range of distances from the Sun poorly covered by direct exploration, improving the constraints on the fundamental theories of gravitation and on the behaviour of the solar wind and the interplanetary magnetic field.Comment: 29 pages, 4 figures; accepted for publication on the special issue "The outer Solar System X" of the journal Planetary and Space Science. This article presents an updated and expanded discussion of the white paper "The ODINUS Mission Concept" (arXiv:1402.2472) submitted in response to the ESA call for ideas for the scientific themes of the future L2 and L3 space mission

Annual Progress Report of the European and Global Drought Observatories

With this report, the reader finds an overview of the changes, upgrades and new features created in the European Drought Observatory (EDO) and the Global Drought Observatory (GDO) and made in 2019. The year proved relatively quiet concerning drought events in Europe; the subcontinent was only affected in the Baltics, although fires broke out vigorously in the Balkans, Spain and Russia. Thanks to the recent juvenile concern with regard to the heating up of the climate, drought events and forest fires drew more public-attention. Our reaction upon this concern in the Global Drought Observatory is the development of a new group of data, which we call Drought Mitigation. With more people genuinely concerned in the effect of our alternation of the properties of the lower atmosphere, we take up the task to provide guidelines for repair and adaptation. Higher temperatures imply that air depletes more vapour from vegetation and soil, leading to more intense droughts or floods. Consient management of our fresh water resources and massive tree planting are measures that can have significant impact on the effects of a Drought, Forest Fires or also Flood events. Therefore, we started with including the results of the often-cited research result regarding reforestation potential of the Crowther Lab as a layer in the Global Drought Observatory. We completed our work with enriching data describing dams with data regarding the location, name and quantitative characteristics of dams as an additional layer. We worked on the integration of the GRACE Dataset, which gives us an actualized satellite born, insight in the depletion of groundwater resources. We created a new index, alerting drought impacts on protected wetlands. Droughts events in these areas might affect rare species living in these protected wetlands, thus creating a link to the biodiversity crisis. The drought alerting mechanism we developed thus far were human centred. With this new index and with the Crowther Lab reforestation inventory we hope to correct this one species view of the past, learning to share our territory with all species, also during hard times of a drought disaster. With these additions, we hope that EDO and GDO will give you a better overview of the impacts of drought events, not only for our economy but also for our shared ecosystems and their services to us. Finally note that we engage in a project to export EDO and GDO knowledge and software to African regional partners. Thus enabling them to set up drought observatories in Africa just as if we did for South- and Central America. Such a collaboration works both ways, we understand better the impacts of Drought events in their region and we learn from their practical skills with regard to make things work in a challenging environment, whilst we can give them working drought observatory software, practical manners to, almost, fully automate the filling and updating of the systems combined with our specific expertise on droughts build up in the last 12 years.JRC.E.1-Disaster Risk Managemen

Alkalizing Reactions Streamline Cellular Metabolism in Acidogenic Microorganisms

An understanding of the integrated relationships among the principal cellular functions that govern the bioenergetic reactions of an organism is necessary to determine how cells remain viable and optimise their fitness in the environment. Urease is a complex enzyme that catalyzes the hydrolysis of urea to ammonia and carbonic acid. While the induction of urease activity by several microorganisms has been predominantly considered a stress-response that is initiated to generate a nitrogen source in response to a low environmental pH, here we demonstrate a new role of urease in the optimisation of cellular bioenergetics. We show that urea hydrolysis increases the catabolic efficiency of Streptococcus thermophilus, a lactic acid bacterium that is widely used in the industrial manufacture of dairy products. By modulating the intracellular pH and thereby increasing the activity of β-galactosidase, glycolytic enzymes and lactate dehydrogenase, urease increases the overall change in enthalpy generated by the bioenergetic reactions. A cooperative altruistic behaviour of urease-positive microorganisms on the urease-negative microorganisms within the same environment was also observed. The physiological role of a single enzymatic activity demonstrates a novel and unexpected view of the non-transcriptional regulatory mechanisms that govern the bioenergetics of a bacterial cell, highlighting a new role for cytosol-alkalizing biochemical pathways in acidogenic microorganisms

DETECTION OF WIDESPREAD HYDRATED MATERIALS ON VESTA BY THE VIR IMAGING SPECTROMETER ON BOARD THE DAWN MISSION

Water plays a key role in the evolution of terrestrial planets, and notably in the occurrence of Earth's oceans. However, the mechanism by which water has been incorporated into these bodies—including Earth—is still extensively debated. Here we report the detection of widespread 2.8 μm OH absorption bands on the surface of the asteroid Vesta by the VIR imaging spectrometer on board Dawn. These observations are surprising as Vesta is fully differentiated with a basaltic surface. The 2.8 μm OH absorption is distributed across Vesta's surface and shows areas enriched and depleted in hydrated materials. The uneven distribution of hydrated mineral phases is unexpected and indicates ancient processes that differ from those believed to be responsible for OH on other airless bodies, like the Moon. The origin of Vestan OH provides new insight into the delivery of hydrous materials in the main belt and may offer new scenarios on the delivery of hydrous minerals in the inner solar system, suggesting processes that may have played a role in the formation of terrestrial planets

Ammoniated phyllosilicates with a likely outer Solar System origin on (1) Ceres

This article is in the 99th percentile (ranked 308th) of the 357,891 tracked articles of a similar age in all journals and the 94th percentile (ranked 54th) of the 934 tracked articles of a similar age in Nature. In the top 5% of all research outputs scored by AltmetricStudies of the dwarf planet (1) Ceres using ground-based and orbiting telescopes have concluded that its closest meteoritic analogues are the volatile-rich CI and CM carbonaceous chondrites. Water in clay minerals, ammoniated phyllosilicates, or a mixture of Mg(OH)2 (brucite), Mg2CO3 and iron-rich serpentine have all been proposed to exist on the surface. In particular, brucite has been suggested from analysis of the mid-infrared spectrum of Ceres. But the lack of spectral data across telluric absorption bands in the wavelength region 2.5 to 2.9 micrometres—where the OH stretching vibration and the H2O bending overtone are found—has precluded definitive identifications. In addition, water vapour around Ceres has recently been reported, possibly originating from localized sources. Here we report spectra of Ceres from 0.4 to 5 micrometres acquired at distances from ~82,000 to 4,300 kilometres from the surface. Our measurements indicate widespread ammoniated phyllosilicates across the surface, but no detectable water ice. Ammonia, accreted either as organic matter or as ice, may have reacted with phyllosilicates on Ceres during differentiation. This suggests that material from the outer Solar System was incorporated into Ceres, either during its formation at great heliocentric distance or by incorporation of material transported into the main asteroid belt. <P /