How did lunar craters form? This issue has led to a long discussion between supporters of two hypotheses on the origin of lunar craters: volcanic and meteorite.
According to the volcanic hypothesis, which was put forward by the German astronomer Johann Schröter in the 80s of the 18th century, craters arose as a result of grandiose eruptions on the lunar surface. In 1824, his compatriot Franz von Gruutuisen proposed a meteorite theory that explained the formation of craters by the fall of meteorites.
Only 113 years later, in 1937, a Russian student Kirill Stanyukovich (future doctor of science and professor) proved that when meteorites strike at cosmic velocities, an explosion occurs, as a result of which not only a meteorite is melted, but also some of the rocks at the site of the impact. The explosive theory of Stanyukovich was developed in 1947-1960. by himself, and then by other researchers. 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
Uranus is the seventh planet from the Sun in the solar system. In diameter, it is almost four times larger than the Earth. Very far from the Sun and relatively poorly lit. Uranus was discovered by the English scientist W. Herschel in 1781. It is not possible to distinguish any details on the surface of Uranus due to the small angular dimensions of the planet in the field of view of the telescope. This complicates his research, including the study of the laws of rotation. Apparently, Uranus (unlike all other planets) rotates around its axis as if lying on its side. Such an inclination of the equator creates unusual lighting conditions: at the poles in a certain season, the sun’s rays fall almost vertically, and the polar day and polar night cover (alternately) the entire surface of the planet, except for a narrow strip along the equator. Since Uranus Continue reading
Saturn is the second largest among the planets of the solar system. Its equatorial diameter is only slightly smaller than that of Jupiter, but Saturn is more than three times as massive as Jupiter and has a very low average density – about 0.7 g / cm3. The low density is due to the fact that the giant planets are composed mainly of hydrogen and helium. Moreover, in the bowels of Saturn, the pressure does not reach such high values as on Jupiter, so the density of matter there is less. Spectroscopic studies found some molecules in Saturn’s atmosphere. The surface temperature of the clouds on Saturn is close to the melting point of methane (-184 ° C), of which the cloud layer of the planet most likely consists of solid particles. Dark bands elongated along the equator, also called belts, and bright zones are visible through the telescope, Continue reading
Jupiter, the fifth largest in the distance from the Sun and the largest planet in the Solar System, is 5.2 times farther from the Sun than the Earth, and spends almost 12 years in orbit. The equatorial diameter of Jupiter is 142,600 km (11 times the diameter of the Earth). The rotation period of Jupiter is the shortest of all the planets – 9h 50 min 30s at the equator and 9h 55min 40s in the middle latitudes. Thus, Jupiter, like the sun, does not rotate like a solid – the rotation speed is not the same at different latitudes. Due to the fast rotation, this planet has a strong compression at the poles. The mass of Jupiter is equal to 318 Earth masses. The average density is 1.33 g / cm3, which is close to the density of the Sun. The axis of Continue reading