Gravitational Lensing and Wormhole Shadows

Astronomy Reports - The problem of bending and scattering of light rays passing outside the entrance of a wormhole with zero gravitational mass is considered. The process of ray capture by a...     

Carboniferous 40Ar/39Ar Age of Rare-Metal Enriched Rhyolites and Ignimbrites in the Sakmara Allochthon (Southern Urals)

Doklady Earth Sciences - The Sakmara Allochthon (Southern Urals) comprises a widely distributed folded stratum of rhyolites and ignimbrites, which are characterized by Nb–Zr–REE...     

Biogenic nanogoethite in the weathering crust of the basalts of Vietnam: Crystal morphology and thermal and magnetic properties

Studies of the mineral substance in the weathering crust (CW) of the basalts of Vietnam have shown that these basalts might be considered as a natural laboratory for the formation of mineral bionanostructures of specific crystal morphology and thermal and magnetic properties. It is suggested that the crystallization of goethite in the cuirass and underlying bauxites of the CW of Vietnam resulted from the coagulation of colloidal particles and of hydrated iron oxide under the impact of bacterial colonies, which determined the specific features.     

A new method for determining the masses of black holes

Characteristic properties of the electromagnetic spectrum of a dipole freely falling radially toward a Schwartzschild black hole are determined. These properties can be used to determined the mass of the black hole, as well as some characteristics of the magnetosphere or accretion disk surrounding the black hole.     

Cobalt-Rich Ferromanganese Crusts of the Govorov Guyot of the Magellan Seamounts of the Pacific Ocean: Conditions of Occurrence,Mineralogy, and Geochemistry

Oceanology - The article describes the geological conditions of the formation of cobalt-rich ferromanganese crusts on the Govorov guyot in the Magellan Seamount system of the Pacific Ocean. It is...     

I.S. Shklovskii,black holes and subsequent developments

The paper is dedicated to the evolution of the views of I.S. Shklovskii on black holes, his contribution to studies of astrophysical manifestations of black holes, and subsequent studies of these surprising objects.     

Kinetics and mechanism of transformations in iron-rich pyrrhotites and in troilite-pyrrhotite metastable assemblages

Iron-rich pyrrhotites proved to be metastable and to decompose at 70–140° C to troilite and pyrrhotite with less iron content as shown by nuclear gamma-resonance (Mössbauer) studies at high temperatures. Coherence of decomposition product lattices was established by studying powder samples textured in a magnetic field. Detailed X-ray powder diffraction and Mössbauer investigations revealed two different mechanisms of transformation in metastable associations. Kinetic phenomena are discussed in terms of a thermodynamic model of two-phase assemblage.     

Geological and macroseismic manifestations of the earthquake on October 16, 2011 in the Skovorodino region, Amur oblast

The epicentral zone and settlements that suffered from the M _S = 6.1 earthquake in the northwest Amur oblast are examined. Only secondary seismic dislocations were revealed and mapped in detail. The inspection of settlements and inhabitansts inquiry allowed estimation of the intensity of the macroseismic effect based on the MSK-64 scale. These forthwith primary factual data give an idea on the shaking intensity at the distant and nearest zones and precise location of the earthquake focus. The map of isoseists of the highest (7–8) intensity is drawn.     

The Oligocene gap in the formation of Co-rich ferromanganese crusts and sedimentation in the Pacific Ocean and the effects of bottom currents

The Marcus Wake and Magellan guyots formed about 129–74 Ma ago at 10°–30° S and drifted 1700–4400 km to their present-day latitudinal position across the equatorial zone of maximum deposition. Cooling of the Pacific plate brought these guyots to the northern arid zone during the Turonian–Maastrichtian, to depths at which sediment accumulation rates were low and the conditions promoted precipitation of Co-rich Fe–Mn crusts from the Campanian to the present. Nonprecipitation of Co-rich Fe–Mn crusts during the Oligocene was caused by the action of bottom currents. The presence of a hiatus identified in cores from drill holes was used as the basis for reconstruction of the directions of bottom currents in the Oligocene.