Deimos and Phobos. "Fear and horror"

Deimos and Phobos are small by the cosmic standards of the companions of our neighbor, Mars. Despite their rather menacing names, they look modest against the background of the other celestial bodies of the solar system. Nevertheless, the "Fear" and "Horror" accompanying Mars in its eternal whirlpool orbit, are of great value to researchers and are of considerable interest to astrophysicists.

Prediction of the writer

Few know that the discovery of the satellites of Mars first occurred not in the observatory, but in the pages of the famous work of Jonathon Swift "The Adventures of Gulliver." The protagonist in one of the chapters, scientists from the flying island of Laputa told us about the two bodies they discovered, moving around Mars. The story of the adventures of Gulliver appeared in the early eighteenth century. The scientific discovery of Phobos and Deimos took place much later - in 1877. A. Hall performed it during the great confrontation of the Red Planet. The opening is worthy of perpetuation for many reasons: it was made possible by exceptionally successful weather conditions and the incredible work of the scientist, in whose arsenal were only quite imperfect instruments of the late nineteenth century.

Crumbs

Deimos and Phobos are not available for study with amateur equipment due to their modest size. They are many times smaller than the Moon. The Deimos satellite is the tiniest similar object in the entire Solar system. Phobos is somewhat larger than its "fellow", but also can not boast of impressive dimensions. Since the beginning of the era of cosmonautics, both objects have been studied with the help of several apparatuses: Viking-1, Mariner-9, Phobos, Mars-Express. During the research, images of satellites were obtained, as well as data on the nature of their surface and composition.

Origin

To date, the question of where the satellites originated from Mars is unclear. One of the probable versions says that Deimos and Phobos are asteroids captured by the Red Planet. And they assume that they flew from remote parts of the solar system or even formed outside its borders. Less plausible scientists call the hypothesis of the origin of satellites from the main belt of asteroids. Perhaps a certain role in the appearance of such a "suite" in Mars was played by the giant Jupiter, with its powerful gravitational field distorting the orbits of all asteroids passing by.

"Fear"

Phobos is the closest satellite to the planet. Like Deimos, it has an irregular shape and moves in an almost circular orbit around Mars. Phobos is always turned to the planet by one side, which is similar to the Moon. The reason for this is the coincidence of the periods of rotation of the body around Mars and around its axis.

The orbit of Phobos is very close to the Red Planet. According to scientists, the satellite under the action of the gravitational field of Mars is gradually decreasing (slightly less than ten centimeters per year). In the distant future, he is threatened with destruction. Either in about 11 million years, Phobos will fall to Mars, or a little earlier, in 7 million years, will be torn by the gravitational forces of the planet and forms around it a ring of debris.

Surface

Phobos and Deimos are satellites covered with traces from meetings with meteorites. The surface of both is covered with craters of different sizes. The largest of them is located on Phobos. The diameter of the crater is 10 km, for comparison, the size of the satellite itself is 27 by 21 km. The blow that left such a trace could easily lead to the complete destruction of this cosmic body.

The surface of Phobos has one more feature that distinguishes it from the "fellow". These are practically parallel furrows up to several hundred meters wide, occupying a vast area. Their origin remains a mystery. Under the assumptions of scientists, they can also be the consequences of a powerful blow or be a consequence of the gravitational impact of Mars.

"Horror"

Deimos measures 15 by 12 kilometers and circles along a more distant orbit than Phobos: the distance to the planet is about 23.5 thousand kilometers. One turn around Mars "Horror" commits for 30 hours and 18 minutes, which is slightly longer than the duration of the day on the planet and more than four times slower than the movement of Phobos. He suffices to fly around the planet 7 hours and 39 minutes.

Deimos, in contrast to his "fellow" is not going to fall. Some scientists suggest that the probable fate of "Horror" is to overcome the attraction of Mars and fly into space.

Structure

For a long time it remained incomprehensible that they hide Deimos and Phobos inside. Scientists knew only about the suspiciously low density of these bodies, calculated in the process of observations from the Earth. In connection with these data, the most fantastic assumptions arose about which objects were escorted by Mars. Phobos and Deimos in some hypotheses were listed as artificial hollow satellites, created in the extreme antiquity and, possibly, by the civilization of another planet.

After studying the data obtained by spacecraft, it was discovered that the "suite" of Mars is more like asteroids, that is, natural objects. The density of matter on the satellites was calculated at about 2 g / cm ³ . A similar indicator occurs in some meteorites. Today, the low density of the Mars satellites is explained by the peculiarities of their structure: presumably Phobos and Deimos consist of a mixture of carbon-rich rocks with ice. In addition, the photographs of spacecraft suggest that the surface of the object closest to Mars is covered with a meter layer of dust, similar to the regolith of the Moon.

The "retinue" of the Red Planet still holds many secrets, therefore among astronomers the projects of flights to it are constantly being developed. Of great interest is Mars himself. In some projects it is considered as a candidate for terraforming or a suitable place for the extraction of some resources. At first glance, a fantastic perspective of placing research bases first on the Moon and then on Mars is seriously discussed in scientific circles. In addition, the study of such objects can always bring information not only about themselves, but also about the solar system, its formation and features. And even about the universe as a whole.