Sunspot Observations Made by Hallaschka During the Dalton Minimum

We present and analyse the sunspot observations performed by Franz I.C. Hallaschka in 1814 and 1816. These solar observations were carried out during the so-called Dalton minimum, around the maximum phase of Solar Cycle 6. These records are very valuable because they allow us to complete observational gaps in the collection of sunspot group numbers, improving the coverage for this epoch. We have analysed and compared the observations made by Hallaschka with the records made by other contemporary observers. Unfortunately, the analysis of the sunspot areas and positions showed that they are too inaccurate for scientific use. We conclude, however, that the sunspot counts made by Hallaschka are similar to those made by other astronomers of that time. The observations by Hallaschka confirm a low level of solar activity during the Dalton minimum.     

Magnetic Lasso: A New Kinematic Solar Wind Propagation Method

Solar wind propagation from the point of measurement to an arbitrary target in the heliosphere is an important input for heliospheric, planetary and cometary studies. In this paper a new kinematic propagation method, the magnetic lasso method is presented. Compared to the simple ballistic approach our method is based on reconstructing the ideal Parker spiral connecting the target with the Sun by testing a previously defined range of heliographic longitudes. The model takes into account the eventual evolution of stream–stream interactions and handles these with a simple model based on the dynamic pressure difference between the two streams. Special emphasis is given to input data cleaning by handling interplanetary coronal mass ejection events as data gaps due to their different propagation characteristics. The solar wind bulk velocity is considered radial and constant. Density and radial magnetic field are propagated by correcting with the inverse square of the radial distance. The model has the advantage that it can be coded easily and fitted to the problem; it is flexible in selecting and handling input data and requires little running time.     

Charged isotropic model with conformal symmetry

We investigate the behaviour of a charged isotropic model with conformal symmetry. The relationship between the gravitational potentials arising from the conformal condition is used to generate a new class of exact solutions to the Einstein-Maxwell equations. A specific form of the electric field intensity and the metric potential is required to avoid a singularity at the centre. We can find simple elementary functions for the matter variables and the potentials with realistic profiles. The causality conditions, stability conditions and energy conditions are satisfied. Masses, radii, central densities and surface redshifts are generated, and the values are consistent with the compact stars 4U 1538-52 and PSR J1614-2230.     

Comets,Enceladus and panspermia

A growing body of evidence suggests the operation of life and life processes in comets as well in larger icy bodies in the solar system including Enceladus. Attempts to interpret such data without invoking active biology are beginning to look weak and flawed. The emerging new paradigm is that life is a cosmic phenomenon as proposed by Hoyle and Wickramasinghe (Lifecloud: the Origin of Life in the Galaxy, 1978) and first supported by astronomical spectroscopy (Wickramasinghe and Allen, Nature 287:518, 1980; Allen and Wickramasinghe, Nature 294:239, 1981; Wickramasinghe and Allen, Nature 323:44, 1986). Comets are the transporters and amplifiers of microbial life throughout the Universe and are also, according to this point of view, the carriers of viruses that contribute to the continued evolution of life. Comets brought life to Earth 4.2 billion years ago and they continue to do so. Space extrapolations of comets, Enceladus and possibly Pluto supports this point of view. Impacts of asteroids and comets on the Earth as well as on other planetary bodies leads to the ejection of life-bearing dust and rocks and a mixing of microbiota on a planetary scale and on an even wider galactic scale. It appears inevitable that the entire galaxy will be a single connected biosphere.     

Analysis of Design Characteristics of Snake-Type Atmospheric Probes (Vetrolets) for Studying the Atmosphere of Venus

In Russia, work aimed at designing a spacecraft for the long-term exploration of Venus is currently underway as part of the VENUS-D project. The R&D work proposes the concept of a snake-type atmospheric probe intended for exploring the atmosphere of Venus. This article describes the principles of flight, considers the main design features and engineering characteristics of the probes, and provides recommendations for engineering solutions.     

On the Trajectories of Asteroid Encounters with the Earth for 2015 RN35 and Apophis

A great number of probable encounters of asteroid 2015 RN35 with the Earth have been found; many of them were unknown earlier. The main characteristics and properties of the corresponding trajectories have been obtained. Probable impacts of the asteroid Apophis with the Earth are also discussed. The results suggest that the multitudes of potential impacts of hazardous asteroids with the Earth can be and must be analyzed in more detail. Such an analysis is required to plan and implement the measures on preventing the asteroid impact hazard.     

Creating an isotopically similar Earth–Moon system with correct angular momentum from a giant impact

The giant impact hypothesis is the dominant theory explaining the formation of our Moon. However, the inability to produce an isotopically similar Earth–Moon system with correct angular momentum has cast a shadow on its validity. Computer-generated impacts have been successful in producing virtual systems that possess many of the observed physical properties. However, addressing the isotopic similarities between the Earth and Moon coupled with correct angular momentum has proven to be challenging. Equilibration and evection resonance have been proposed as means of reconciling the models. In the summer of 2013, the Royal Society called a meeting solely to discuss the formation of the Moon. In this meeting, evection resonance and equilibration were both questioned as viable means of removing the deficiencies from giant impact models. The main concerns were that models were multi-staged and too complex. We present here initial impact conditions that produce an isotopically similar Earth–Moon system with correct angular momentum. This is done in a single-staged simulation. The initial parameters are straightforward and the results evolve solely from the impact. This was accomplished by colliding two roughly half-Earth-sized impactors, rotating in approximately the same plane in a high-energy, off-centered impact, where both impactors spin into the collision.     

Behaviour of physical parameters in extended gravity with hyperbolic function

In this paper, we have constructed the cosmological model of the universe in f(R, T) theory of gravity in a Bianchi type \(\mathrm{VI}_h\) universe for the functional f(R, T) in the form \(f(R,T)=\mu R+\mu T\), where R and T are respectively Ricci scalar and trace of energy momentum tensor and \(\mu \) is a constant. We have made use of the hyperbolic scale factor to find the physical parameters and metric potentials defined in the space-time. The physical parameters are constrained from different representative values to build up a realistic cosmological model aligned with the observational behaviour. The state finder diagnostic pair is found to be in the acceptable range. The energy conditions of the model are also studied.     

Transition between general relativity and quantum gravity using quark and strange quark matter with some kinematical test

Contemporary piece of writing devotes to the investigation of plane symmetric cosmological model with quark and strange quark matter in the deformations of the Einstein’s theory of General Relativity (GR). At small or large scales (ultraviolet or infrared gravity), deformations of the Einstein’s theory could provide a better handling of cosmic acceleration without magnetism (along with singularities). In particular, a proper deformation of GR in the ultraviolet regime could play the role of describing the transition between GR and quantum gravity. As a matter of fact, although with a different purpose in mind, it was Einstein himself who proposed in the 30’s the reformulation of GR by taking the field of orthonormal frames or tetrads as the dynamical variable instead of the metric tensor (Einstein, Phys. Math. Kl 217, 401, 1928). As per the observation, pressure and energy density of the model approaches the bag constant in negative and positive ways at \(t\rightarrow \infty \), i.e. \(p\rightarrow -B_c \) and \(\rho \rightarrow B_c \), the negative pressure due to the Dark Energy (DE) in the context of accelerated expansion of the universe. So the strange quark matter gives an idea of existence of dark energy in the universe and supports the observations of the SNe-I (Riess et al., Astron. J. 116,1009, 1998; Perlmutter et al., Astrophys. J. 517, 565, 1999). Also these results agree with the study of Aktas and Aygun (Chinese J. Phys. 55, 71, 2017) and Sahoo et al. (New. Astron. 60, 80, 2018).