Satellite Ganymede. Ganymede is a satellite of Jupiter

Satellite Ganymede - the most outstanding object of the suite of Jupiter. The gas giant is among the planets, it stands out among the moons of the solar system in size. By the diameter of Ganymede ahead of even Mercury and Pluto. However, not only because of its size, the satellite of Jupiter captures the eyes of researchers. Many parameters make it an extremely interesting object for astrophysicists: a magnetic field, a relief, an internal structure. In addition, Ganymede is a satellite on which life can theoretically exist.

Opening

The official opening date is January 7, 1610. On this day, Jupiter sent his telescope (the first in history) to Galileo Galilei. He found four satellites from the gas giant: Io, Europe, Ganymede and Kalisto. About a year before, the same objects were observed by Simon Marius, an astronomer from Germany. However, he did not publish the data on time.

Familiar names for cosmic bodies were given by Simon Marius. Galileo also designated them as "the Medici planets" and each assigned a serial number. To call the satellites of Jupiter the names of the heroes of the Greek myths became in fact only from the middle of the last century.

All four cosmic bodies are also referred to as "Galilean satellites". Feature of Io, Europe and Ganymede is that they rotate with an orbital resonance 4: 2: 1. For the time when the largest of the four flies around Jupiter, Europe manages to make 2, and Io - four turns.

Features

The satellite Ganymede is really amazing with its size. Its diameter is 5262 km (for comparison: a similar parameter of Mercury is estimated at 4879.7 km). By gravity, it is twice as high as the moon. At the same time the mass of Ganymede is inferior to the Mercurian more than twice. The reason for this lies in the low density of the object. It is only twice as large as the water. And this is one of the reasons to believe that the substance necessary for the birth of life on Ganymede is present, and in a fairly large number.

Surface

Ganymede is a satellite of Jupiter, some of its features resemble the moon. For example, here there are craters that have remained from fallen meteorites. Their age is estimated at about 3-3.5 billion years. Similar traces of the past are abundantly present on the lunar surface.

Two types of relief can be distinguished on Ganymede. Dark areas, abundantly covered with craters, are considered more ancient. With them, there are "young" areas of the surface, bright and dotted with ridges and grooves. The latter, according to scientists, formed as a result of tectonic processes.

The structure of the satellite's crust, perhaps, resembles a similar structure on Earth. Tectonic plates, which are large pieces of ice on Ganymede, could move and collide in the past, forming faults and mountains. This assumption is confirmed by the discovered frozen streams of ancient lava.

Probably, the light furrows of the younger segments of the satellite were formed as a result of discrepancies between plates, the filling of faults with a viscous substance under the crust, and further restoration of surface ice.

Dark areas are covered with a substance that has meteorite origin or is formed as a result of the evaporation of water molecules. Under its thin cover is, according to researchers, pure ice.

The recent discovery

In April this year, information was released on the opening of two scientists from the United States. At the equator of the satellite Ganymede they discovered a large bulge. Education of its size is comparable with Ecuador and in height reaches half of Mount Kilimanjaro.

A possible reason for the appearance of such a feature of the relief is the drift of surface ice from one of the poles to the equator. Such movement can occur in the event that the ocean is located under the bark of Ganymede. Its existence has long been discussed in the scientific world, and a new discovery can serve as additional evidence of the theory.

Internal structure

Water ice, in the opinion of astrophysicists, is found in large numbers in the depths - another feature that characterizes Ganymede. The largest of the satellites of Jupiter has three internal layers:

• Molten core, consisting either of metal only, or of metal and sulfur impurities;

• Mantle, consisting of rocks;

• Layer of ice in 900-950 km thick.

Perhaps a layer of liquid water lies between the ice and the mantle. In this case, it is characterized by a temperature below zero, but does not freeze due to high pressure. The thickness of the layer is estimated at several kilometers, it lies at a depth of 170 km.

A magnetic field

Sputnik Ganymede is not only tectonics like the Earth. Another remarkable feature of it is a powerful magnetic field, comparable to the similar formation of our planet. Scientists suggest that there can be only two reasons for this phenomenon in the case of Ganymede. The first is the molten core. The second is a layer of salt liquid, which conducts electricity well, under the icy crust of the satellite.

In favor of the latter assumption are the data of the Galileo apparatus, as well as recent studies of the aurora borealis of Ganymede. Jupiter brings discord into the magnetic field of the satellite. As it was possible to establish during the study of the aurora, their magnitude is much lower than expected. Probable cause of deviations is a liquid subsurface ocean. Its thickness can be up to 100 km. In such an interlayer, more water should be contained than on the entire surface of the Earth.

Such theories provide an opportunity to seriously consider the likelihood that Ganymede is a satellite where there is life. The possibility of this indirectly confirms the discovery of organisms on the Earth in conditions that seemingly little suited to it: in thermal springs, at the depth of the ocean with almost complete absence of oxygen and so on. While satellite Ganymede is recognized as a likely candidate for the possession of extraterrestrial life. Whether this is so, they will be able to establish only new flights of interplanetary stations.