Powders with zero Ohmic resistance.

We substantiate the mechanism of electrical conductivity of powder consisting of dielectric nanoparticles with ionized donor centers on the surface and free electrons in the bulk. It is shown that in a powder switched to a closed dc circuit, the electric field strength vanishes due to the polarization of the powder by the source of the electromotive force. The Ohmic loss becomes impossible. The electrons of the polarized powder are in the states that correspond to the minimum of the powder energy and zero Ohmic resistance. The fulfillment of these conditions does not depend on the temperature (T = 300-500 K) and the strength of the circuit current. The electric current in the powder is maintained on account of the difference in the electrochemical potentials of electrodes that are in contact with the polarized powder.

Substances with zero static permittivity.

The structure of materials with a negative electric susceptibility has been determined. Their electrical properties correspond to vanishing static dielectric permittivity. We give a theoretical explanation of anomalous polarization of powders observed in experiments and the mechanism of emergence in an aerosol cloud of an electric field, which is responsible for spark discharges (lightnings). We also explain the ball lightning properties known from observations. A fundamental scientific problem has been solved and the grounds have been laid for applications of new principles in electronics and electrical engineering.

Chelyabinsk airburst, damage assessment, meteorite recovery, and characterization.

The asteroid impact near the Russian city of Chelyabinsk on 15 February 2013 was the largest airburst on Earth since the 1908 Tunguska event, causing a natural disaster in an area with a population exceeding one million. Because it occurred in an era with modern consumer electronics, field sensors, and laboratory techniques, unprecedented measurements were made of the impact event and the meteoroid that caused it. Here, we document the account of what happened, as understood now, using comprehensive data obtained from astronomy, planetary science, geophysics, meteorology, meteoritics, and cosmochemistry and from social science surveys. A good understanding of the Chelyabinsk incident provides an opportunity to calibrate the event, with implications for the study of near-Earth objects and developing hazard mitigation strategies for planetary protection.