Studies of strong gravitational fields near super-massive black hole horizons with space missions

General relativity (GR) can be probed by several tests in the weak gravitational field limit. On the contrary, very poor information exists about GR tests in strong gravitational fields. Here, we focus on the interaction of light rays with the strong gravitational field of a massive black hole and show that relativistic images may form. Hence, we calculate the shapes of shadows (mirages) forming just near BH horizons and discuss the possibility to estimate the black hole parameters (mass, spin and charge) by future astrometric missions. In 2007, the Radioastron space telescope will be launched and it will allow to evaluate those parameters for the black hole hosted at the center of our Galaxy.     

Large-size message construction for ETI: Inductive self-interpretation in LINCOS

Ingredients of the author's Lingua Cosmica for communication with extra-terrestrial intelligent beings are examined with self-interpretation in mind. The most important ingredients for that purpose are inductive definitions. These definitions contain ordered sequences of induction hypotheses, identified by mutually distinctive constructors. If an assertion involving an inductive definition is to be verified, all induction hypotheses must be taken into account, i.e. they must be eliminated one by one. The implementation of the elimination procedure can be expressed within LINCOS itself. Therefore the system admits self-interpretation.     

Use of halophytic plants for recycling NaCl in human liquid waste in a bioregenerative life support system

The purpose of this work was to develop technology for recycling NaCl containing in human liquid waste as intrasystem matter in a bioregenerative life support system (BLSS). The circulation of Na⁺ and Cl⁻ excreted in urine is achieved by inclusion of halophytes, i.e. plants that naturally inhabit salt-rich soils and accumulate NaCl in their organs. A model of Na⁺ and Cl⁻ recycling in a BLSS was designed, based on the NaCl turnover in the human–urine–nutrient solution–halophytic plant–human cycle. The study consisted of (i) selecting a halophyte suitable for inclusion in a BLSS, and (ii) determining growth conditions supporting maximal Na⁺ and Cl⁻ accumulation in the shoots of the halophyte growing in a nutrient solution simulating mineralized urine. For the selected halophytic plant, Salicornia europaea, growth rate under optimal conditions, biomass production and quantities of Na⁺ and Cl⁻ absorbed were determined. Characteristics of a plant production conveyor consisting of S.europaea at various ages, and allowing continuity of Na⁺ and Cl⁻ turnover, were estimated. It was shown that closure of the NaCl cycle in a BLSS can be attained if the daily ration of fresh Salicornia biomass for a BLSS inhabitant is approximately 360 g.     

Estimated errors in a global gravity wave climatology from GPS radio occultation temperature profiles

In a previous paper by Schmidt et al. (2008), from CHAllenging Minisatellite Payload (CHAMP) Global Positioning System (GPS) radio occultation data, a comparison was made between a Gaussian filter applied to the “complete” temperature profile and to its “separate” tropospheric and stratospheric height intervals, for gravity wave analyses. It was found that the separate filtering method considerably reduces a wave activity artificial enhancement near the tropopause, presumably due to the isolation process of the wave component. We now propose a simple approach to estimate the uncertainty in the calculation of the mean specific wave potential energy content, due exclusively to the filtering process of vertical temperature profiles, independently of the experimental origin of the data. The approach is developed through a statistical simulation, built up from the superposition of synthetic wave perturbations. These are adjusted by a recent gravity wave (GW) climatology and temperature profiles from reanalyses. A systematic overestimation of the mean specific wave potential energy content is detected and its variability with latitude, altitude, season and averaging height interval is highlighted.     

AB beam propulsion for interplanetary flights

The author offers a revolutionary method—non-rocket transfer of energy and thrust into Space with a distance of millions of kilometers. The author has developed the theory and made the computations. The method is more efficient than transmission of energy by high-frequency waves. The method may be used for space launch and for accelerating the spaceship and probes for very high speeds, up to a relativistic speed by the current technology. The research also contains prospective projects which illustrate the possibilities of the suggested method.     

Evaluation of uncertainty in gravity wave potential energy calculations through GPS radio occultation measurements

The application of the Global Positioning System (GPS) radio occultation (RO) method to the atmosphere enables the determination of height profiles of temperature, among other variables. From these measurements, gravity wave activity is usually quantified by calculating the potential energy through the integration of the ratio of perturbation and background temperatures between two given altitudes in each profile. The uncertainty in the estimation of wave activity depends on the systematic biases and random errors of the measured temperature, but also on additional factors like the selected vertical integration layer and the separation method between background and perturbation temperatures. In this study, the contributions of different parameters and variables to the uncertainty in the calculation of gravity wave potential energy in the lower stratosphere are investigated and quantified. In particular, a Monte Carlo method is used to evaluate the uncertainty that results from different GPS RO temperature error distributions. In addition, our analysis shows that RO data above 30 km height becomes dubious for gravity waves potential energy calculations.     

Constraining Fundamental Constants of Physics with Quasar Absorption Line Systems

We summarize the attempts by our group and others to derive constraints on variations of fundamental constants over cosmic time using quasar absorption lines. Most upper limits reside in the range 0.5–1.5×10^?5 at the 3σ level over a redshift range of approximately 0.5–2.5 for the fine-structure constant, α, the proton-to-electron mass ratio, μ and a combination of the proton gyromagnetic factor and the two previous constants, g _p(α ²/μ) ^ν , for only one claimed variation of α. It is therefore very important to perform new measurements to improve the sensitivity of the numerous methods to at least <0.1×10^?5 which should be possible in the next few years. Future instrumentations on ELTs in the optical and/or ALMA, EVLA and SKA pathfinders in the radio will undoutedly boost this field by allowing to reach much better signal-to-noise ratios at higher spectral resolution and to perform measurements on molecules in the ISM of high redshift galaxies.     

Simultaneous determination of aerosol- and surface characteristics from top-of-atmosphere reflectance using MERIS on board of ENVISAT

The determination of aerosol optical thickness (AOT) from nadir scanning multi-spectral radiometers, like SeaWiFS, MERIS or MODIS, requires the separation of spectral atmospheric and surface properties. Since SeaWiFS and MERIS do not provide information at 2.1 μm, like MODIS, the estimation of the surface reflectance cannot be made by the cross correlation approach described by Kaufman et al., 1997. The BAER approach (Bremen AErosol Retrieval), von Hoyningen-Huene et al., 2003, uses a linear mixing model of spectra for ‘green vegetation’ and ‘bare soil’, tuned by the NDVI, determining an apparent surface to enable this separation of aerosol and surface properties from VIS and NIR channels. Thus AOT can be derived over a wide range of land surfaces for wavelengths <0.67 μm. Using MERIS L1 data over Europe, the AOT retrieved is comparable with ground-based observations, provided by AERONET. Regional variation of AOT can be observed, showing the atmospheric variability for clear sky conditions by: large scale variation of aerosol turbidity, regional pollution, urban regions, effects of contrails and cases of aerosol-cloud interaction. Simultaneously with the spectral AOT also spectral surface reflectance is obtained, where all atmospheric influences have been considered (molecules, aerosols and absorbing gases (O₃)) for channels with wavelengths <0.67 μm. The AOT is extrapolated by Angström power law to NIR channels and the atmospheric correction for land surface properties is performed, enabling the further investigation of land use and spectral land properties.     

Rosetta Radio Science Investigations (RSI)

The Rosetta spacecraft has been successfully launched on 2nd March 2004 to its new target comet 67 P/Churyumov-Gerasimenko. The science objectives of the Rosetta Radio Science Investigations (RSI) experiment address fundamental aspects of cometary physics such as the mass and bulk density of the nucleus, its gravity field, its interplanetary orbit perturbed by nongravitational forces, its size and shape, its internal structure, the composition and roughness of the nucleus surface, the abundance of large dust grains, the plasma content in the coma and the combined dust and gas mass flux. The masses of two asteroids, Steins and Lutetia, shall be determined during flybys in 2008 and 2010, respectively. Secondary objectives are the radio sounding of the solar corona during the superior conjunctions of the spacecraft with the Sun during the cruise phase. The radio carrier links of the spacecraft Telemetry, Tracking and Command (TT&C) subsystem between the orbiter and the Earth will be used for these investigations. An Ultrastable oscillator (USO) connected to both transponders of the radio subsystem serves as a stable frequency reference source for both radio downlinks at X-band (8.4 GHz) and S-band (2.3 GHz) in the one-way mode. The simultaneous and coherent dual-frequency downlinks via the High Gain Antenna (HGA) permit separation of contributions from the classical Doppler shift and the dispersive media effects caused by the motion of the spacecraft with respect to the Earth and the propagation of the signals through the dispersive media, respectively. The investigation relies on the observation of the phase, amplitude, polarization and propagation times of radio signals transmitted from the spacecraft and received with ground station antennas on Earth. The radio signals are affected by the medium through which the signals propagate (atmospheres, ionospheres, interplanetary medium, solar corona), by the gravitational influence of the planet on the spacecraft and finally by the performance of the various systems involved both on the spacecraft and on ground.     

Topologically Characterized Movement Patterns: A Cognitive Assessment

Abstract

In this paper, we discuss the role of topology as a predictor for the conceptualization of dynamically changing spatial configurations (referred to as movement patterns). We define meaningful units of movement patterns as paths through a topologically defined conceptual neighborhood graph. Topology plays a central role in formal approaches to human cognition and in predicting cognitive similarity ratings—although primarily for static spatial configurations. Formal specifications of the role of topology for characterizing movement patterns do exist, yet there is paucity of behavioral validation. To bridge this gap, we conducted an experiment based on the grouping paradigm to assess factors that underlie conceptualizations of movement patterns. The experiment was designed such that paths through the conceptual neighborhood graph were distinguished by topologically differentiated ending relations. We believe topology can make an important contribution in explaining movement conceptualizations. One recently formulated topology-based contribution is the endpoint hypothesis, asserting that a cognitive focus is placed on event ending relations. We discuss the results of our experiment in relation to previous experiments targeted toward a framework for modeling the cognitive conceptualization of dynamically changing spatial relations.