The mechanical properties of various components of the Chelyabinsk meteorite are studied. A measurement technique allowing one to obtain a strength certificate of the material by a minimum necessary number of samples with allowance for defectiveness is developed. Universal expressions for the chondritic component and impact melting have been obtained. The expressions allow one to make general estimates of the strength boundaries for LL type meteorites.

The best-known, most well-studied diamondiferous rocks are kimberlites and lamproites. Diamonds are also found in impactites, metamorphic rocks, ophiolites, and modern volcanic rocks. Diamonds from these rocks differ from kimberlitic diamonds in size, morphology, trace-element and isotope composition, and physical properties. Differences in these characteristics are related to their different mechanisms of origin. In some cases, diamonds can be formed in “metastable” conditions under disequilibrium thermodynamic parameters, supporting the conclusion that diamond is a polygenetic mineral, formed in nature under different physicochemical and geodynamic conditions. According to thermodynamic considerations and calculations, “metastable” crystallization of diamond is mainly controlled by the size of the forming crystallites. The main effectors in decreasing the energetic barrier for nanosized diamonds are surface tension and related surface energy.

Samples of the Chelyabinsk meteorite fallen in February 15, 2013, near Chelyabinsk, Russia, are analyzed by Raman spectroscopy. Olivines (forsterite), orthopyoxenes (enstatite), plagioclases...

In this paper, we discuss the possible disruption of a prolate ellipsoidal small body by the Earth’s tidal forces during a close flyby. An exact expression for the stress tensor under the action of gravity, rotation, and tidal forces is obtained using the analytical solution of the elastic problem. Constraints for the critical distance are derived taking into account the size, shape, density, mechanical properties (material strength and Poisson ratio), rotation, and two variants of the body orientation. Asteroid 433 Eros is considered as a case study. The results are important for methods for assessing the asteroid hazard of near-Earth objects (NEO) and the evolution of terrestrial planets.