When meteorites fall, they are covered with glass and mineral crystals

This discovery will help scientists better understand the processes that occur with meteorites when they fall.

Physicists from the Ural Federal University have found out that meteorites are covered with a crust of glass and mineral crystals when they fall to the ground. This will help scientists better understand the processes that occur with meteorites when they fall, the UrFU Department of Scientific Communications told TASS.

"Physicists from the joint research laboratory of UrFU and the Institute of Geology and Geochemistry of the Ural Branch of the Russian Academy of Sciences studied the Ozerki and Chelyabinsk meteorites and found out that a crust of glass, mineral crystals and noble metals (platinoids) forms on stony meteorites when they fall to the Earth. <…> According to scientists, during the ablation process, refractory metals are concentrated in the melt and move along with this melt deep into the meteorite, and then solidify in the form of a fusion crust," the report says.

The mechanism of formation of the melting crust in meteorites, on the one hand, will help physicists to understand and explain the processes that occur with meteorites when they fall to Earth, and on the other hand, it can be useful to metallurgists in the technologies of enrichment of materials with noble refractory metals.

"Stone meteorites are multimineral, they contain almost the entire periodic table. But when a chondrite flies into the atmosphere - its speed can reach 50 km / s or more - the ablation process begins: due to friction with air, among other things, the surface heats up and melts. Volatile substances fly off, and refractory substances are concentrated in the melt. Due to ablation, a meteorite can lose up to 99% of its volume. For example, according to various estimates, only 0.1 of the entire meteorite reached the ground from the Chelyabinsk meteorite," explains the process the head of the laboratory of space mineralogy and materials science of UrFU Viktor Grokhovsky.

He noted that the reason for the concentration of platinum group metals in the melting crust of stony meteorites remains unclear. Scientists believe that this occurs as a result of the interaction of the meteorite with the Earth's atmosphere due to the activity of oxygen. "But we still have to prove this experimentally: for this purpose, the Department of Experimental Physics of UrFU has one of the most powerful plasmatrons, which our colleagues have modified. They installed a spectrograph that allows tracking the dynamics of evaporation of elements from the surface of meteorites during ablation. With the help of this device, we plan to obtain a series of high-precision spectral images, which will help track the processes occurring on the surface of meteorites over time," Grokhovsky added.

The work of the physicists was supported by the Ministry of Education and Science of Russia under the Priority-2030 development program and the Russian Science Foundation.

Source: nauka.tass.ru