by Boris KHRENOV, Dr. Sc. (Phys. & Math.), leading research assistant of the Skobeltsyn Research Institute of Nuclear Physics. Lomonosov Moscow State University
The upper atmosphere (more than 100 km high) is a boundary layer between our planet and Cosmos, which has been attracting attention of researchers for a long time. Ordinary observations with the naked eye of "falling stars" were explained by scientists as luminescence during combustion of extra-terrestrial massive bodies (meteoroids and fireballs) in a night-time upper atmosphere. Luminescence in the polar regions was understood as a result of intrusion of cosmic protons and electrons into the Earth atmosphere. The more detailed observations have shown that in different wavelength ranges the upper atmosphere transmits external electromagnetic radiation in a different degree, which at the time of formation of life on the Earth determined the form of this life. Keen interest in the upper atmosphere properties arose due to the flights of rockets and satellites which crossed all its layers. For orbital satellites the upper atmosphere is a medium in which their braking takes place. In case of re-entry of the descending module through the upper atmosphere, it is prohibited to use parachute for small density of the substance, and the only way to protect it from burning is covering of the module with a heatproof protective layer of sufficient thickness. Perfect knowledge of density distribution throughout the altitude in the upper atmosphere was needed for calculation of such layers.
The atmospheric structure. Right scale-altitude in the atmosphere. Left scale--pressure in mbars.
ATMOSPHERIC STRUCTURE AND COMPOSITION
Recently the problem of coexistence of upper and lower atmospheres drew a special attention. Despite the protective role of the upper atmosphere, the main flux of solar radiation passes through the whole atmosphere and reaches the Earth surface. Her ... Читать далее