Last week, scientists managed to obtain numerous evidence of the existence of the ocean of magma under the surface of the satellite of Jupiter - Io. Now we can say that on all four satellites of Jupiter discovered by Galileo Galilei in the XVII century - Io, Europe, Callisto and Ganymede - there may be oceans of different origin. The properties of these oceans are strikingly different - on Io - these are streams of deadly lava, and under the surface of Europe, on the contrary, as scientists believe, there may be an ocean in which life may exist. However, all these oceans have a common feature - all changes occurring with them are due to the interaction with the tidal forces of Jupiter.
The study of the Jupiter system began to be conducted in the 70s of the last century. The first information was obtained by the spacecraft Pioneer-10 and Pioneer-11, which reached Jupiter and its satellites in 1973 and 1974, respectively. While NASA was busy researching the satellites of Jupiter in the late nineties and early two thousand years, scientists were more concerned about the possibility of a new flight of a space research vehicle to Jupiter, which would allow to collect more complete and detailed information. The NASA automatic interplanetary station, called “Juno”, will provide some information about Jupiter’s satellites when it reaches them in 2016. Those who are seriously interested in space and want to get detailed data will have to wait for the next major European space mission - JUICE (JUpiter ICy moon Explorer - Study of the icy satellites of Jupiter). It is assumed that in 2022 an automatic apparatus will be launched, which will reach the system of Jupiter by 2030. According to the European Space Agency, the information obtained through this project will make it possible to get a more accurate picture of the possibility of life on Jupiter and its satellites, as well as on the processes of formation of the gas giant system itself.
The main distinguishing feature of the satellite of Jupiter Io are its volcanoes. This satellite is currently the only known cosmic body, in addition to our planet, on which the presence of volcanic activity has been proven. In addition, this activity is much higher than on Earth - Io volcanoes erupt sulfur to an altitude of up to three hundred kilometers during eruptions. The first marks about this amazing fact were made at one time by Galileo Galilei, and in 1979, the first images were taken from the Voyager spacecraft that confirmed the presence of volcanoes on the surface of the Io satellite. Scientists for many years did not cease to occupy the question - why these volcanoes are not in those places where they should have been located according to computer models? According to new research, this fact can be explained by the presence of magma ocean under the surface of Io, which is a huge source of thermal energy. These data were obtained in 2011, based on information from the NASA Galileo spacecraft, which was launched to Jupiter in order to study this planet and its satellites. The device was able to pass less than three hundred kilometers from the satellites of Jupiter, which made it possible to transfer fairly detailed images to Earth. According to the research, today with a high degree of probability we can speak about the presence of an ocean of magma under the surface of Io.
The surface of Europe is covered with cracks. This fact was established by the spacecraft in the 1970s, and then confirmed by more detailed observations from the Galileo spacecraft in the 1990s and 2000s. As it turned out, the cracks are located not at all in those areas where they were originally expected to be seen, even during the study of the motion of the satellite around Jupiter. However, the presence of the ocean beneath them may well explain this fact. In general, the relatively young surface of Europe clearly indicates that it has somehow been transformed. In 2013, scientists recorded a water jet from Europe, but in the past few years, the phenomenon has not repeated. It is not known whether there is liquid water in the ocean of Europe that could support life. There are several films in which discussions about this issue unfold. One of such films is the documentary “The Tale of Europe”.
A little earlier, this year, Ganymede was observed with the help of the Hubble Space Telescope. The satellite has its own magnetic field, which is significantly affected by the magnetic environment of Jupiter. Observing how the two types of aurorae created by magnetic fields move around the planet, scientists concluded that below exactly there should be an underground ocean with salt water, potentially capable of maintaining the viability of elementary species as well as in Europe.
In 1998, after observing Europe, scientists began to suspect that Callisto also had its own underground ocean. When the Galileo spacecraft discovered the electric current caused by Europe’s liquid ocean, scientists began to observe Callisto and soon discovered a similar situation. Such electrical discharges can only be explained by exposure to the ocean. Be that as it may, Callisto is the most distant satellite of Jupiter, which is why he receives the same amount of tidal energy as Europe. Such energy is more conducive to life on Europe than on Callisto.
Enceladus and others
In the Solar System there are other bodies on which the ocean may also be well. These include Enceladus - satellite of Saturn. It is on it that water streams have been noticed more than once, however, scientists have every reason to talk about something more fascinating, namely, the presence of a huge ocean. Just a month earlier, observations from the Cassini spacecraft showed that the lunar orbit around Saturn oscillates in a sequential direction towards the ocean under a ball of ice. Among other unusual capabilities of Saturn’s moons, Titan can be mentioned, on the surface of which lakes of liquid methane and ethane are found.