Asteroids are so small that gravity is negligible. She is not able to give them the shape of a ball, which gives the planets and their large companions, crushing and ramming their substance. An important role is played by the phenomenon of fluidity. The high mountains on Earth at the bottom “sprawl”, because the strength of the rocks is insufficient to withstand loads of many tons per 1 cm3, and the stone, without crushing, without breaking, flows, although very slowly.
On asteroids with a diameter of up to 300-400 km, due to their low weight, such a phenomenon of fluidity is completely absent, while on the largest asteroids it occurs extremely slowly, and even then only Continue reading
The history of the evolution of the moon is interesting not only in itself, but also as part of the general problem of the origin of the Earth and other planets of the solar system. Recently, we have learned a lot about the physical and chemical characteristics of the moon. These data were obtained not only from the Earth, but also with the help of spacecraft. For example, the automatic stations Surveyor-5, -6, and -7, which made a soft landing on the moon in 1967 and 1968, made it possible for the first time to determine its chemical composition. Samples of lunar rocks delivered by American astronauts under the Apollo program (1969–1972) and Soviet automatic devices of the Luna series (1970–1976) made it possible to measure their chemical and physical characteristics in detail and determine the age of the moon . Continue reading