Planet Jupiter everything explained.

Jupiter - the fifth in the order away from the Sun and the largest planet in the Solar System. Its mass is slightly less than one thousandth of the mass of the Sun, and together two and a half times greater than the total mass of all other planets in the Solar System. Together with Saturn, Uranus and Neptune, it creates a group of gaseous giants, sometimes also called Jupiter planets.

The planet was known to astronomers in ancient times, it was associated with mythology. The Romans called the planet in honor of the most important deity - Jupiter. Observed from Earth Jupiter, third by brightness, a natural object in the night sky over the Moon and Venus.

The largest planet in the Solar System consists of three-quarters of hydrogen and one-quarter of helium. Its shape resembles a flattened rotary ellipsoid (it has a small but noticeable thickening in the equator plane). The surface of the planet covers several layers of clouds, forming the characteristic stripes visible from Earth. The most famous detail of its surface is discovered in the seventeenth century by the Great Red Spot telescope, which is an anticyclone with a diameter larger than the diameter of the Earth. There are weakly visible rings and a powerful magnetosphere around the planet. It has at least 67 moons. The four largest, called Galilean, discovered Galileo in 1610. Ganymede, the largest of the moons, has a diameter larger than the planet Mercury.

The volume of Jupiter's atmosphere is about 88-92% hydrogen and 8-12% helium (about 1% of the atmosphere is methane, water and ammonia). In terms of mass, Jupiter's atmosphere consists of about 75% hydrogen and 24% helium, about 1% of the mass are the remaining components. The interior of Jupiter contains denser substances, so that its composition is approximately 71% hydrogen, 24% helium and 5% other elements. The atmosphere contains traces of methane, water vapor, ammonia and silicon compounds. There are also traces of carbon, ethane, hydrogen sulfide, neon, oxygen, phosphine, and sulfur. The outermost layer of the atmosphere contains ammonia in the form of crystals.

The atmospheric proportions of hydrogen and helium are very close to the theoretical composition of the original solar nebula, but the neon in the upper atmosphere only occurs at a mass concentration of 20 ppm, which is about one tenth of the concentration found on the Sun. The atmosphere is also slightly poorer in helium - it contains about 80% of helium in the Sun. Reducing its content may be the result of condensation and helium precipitation to its deeper layers. The content of heavier inert gases in Jupiter's atmosphere is about two to three times higher than on the Sun.

The mass of Jupiter is 2.5 times greater than the total mass of all other planets. It is so massive that it causes the Solar System's barycentre to shift over the surface of the Sun (the center of mass of the Sun-Jupiter system lies within 1,068 solar rays from the center of the star). Although the diameter of this planet is 11 times larger than the diameter of the Earth, it has a much lower density. The volume of Jupiter is 1321 times the volume of the Earth, and its mass 318 times greater than the Earth's mass. Jupiter has a radius of 0.1 Sun radius, a mass equal to 0.001 of the Sun's mass, which causes it to have a similar density.

If Jupiter increased his mass considerably, he would shrink at the same time. With small changes in mass, the radius of a giant gas type planet almost does not change, and with about four masses of Jupiter the interior becomes compressed enough under the influence of increased gravity, that the planet's volume decreases, despite the increasing amount of matter. For this reason, it is believed that Jupiter is a planet with a maximum diameter that a body with such composition and evolution can achieve. Some planets beyond the sun have larger diameters, but these are bodies that are much closer to the stars; larger sizes are the result of much higher insolation and temperature. The process of further shrinking with the increase of mass lasts until the ignition of thermonuclear reactions, which may occur in the case of a brown dwarf with a mass of about 50 masses of Jupiter.

Although Jupiter would have to be about 75 times more massive to become a star, the smallest known red dwarf has only about 16 percent more radius than the planet. Despite the inability of the thermonuclear reactions to occur inside, Jupiter radiates more heat than it receives from the Sun. The amount of heat produced inside the planet is almost equal to the amount obtained from the Sun. This additional radiation is generated according to the Kelvin-Helmholtz mechanism by adiabatic contraction. As a result of this process, the planet's radius is reduced by about 3 cm per year. After the uprising, Jupiter was much hotter, which made it about twice as large as it is now.

It is believed that Jupiter consists of a dense nucleus containing various elements, surrounded by a layer of liquid metallic hydrogen with the addition of helium, and an outer layer composed mainly of molecular hydrogen. In addition to this general outline, the interior structure is unknown. The kernel is often described as rocky, but its exact composition is unknown, as are the properties of materials at the temperature and pressure prevailing at these depths. In 1997, the existence of the nucleus was suggested by gravitational measurements indicating that it has a mass of 12 to 45 Earth masses, or about 3-15% of the total mass of Jupiter. The presence of the nucleus by at least part of Jupiter's history is suggested by the planet-forming models according to which a rocky or ice core, sufficiently massive, is initially formed. to attract a large amount of hydrogen and helium from the protoss solar nebula. In the later history of the planet, the nucleus, if it existed, could be reduced, because convection currents in hot, liquid metallic hydrogen could mix with the molten matter of the nucleus and elevate it into the upper layers of the interior of the planet. The kernel may not even exist; measurements of the gravitational field were not precise enough to reject this hypothesis.

The uncertainty of the models is related to the margin of error in the current measurements of parameters: one of the rotational coefficients (J6) used to describe the gravitational moment, equatorial Jovian radius and temperature at the level at which the pressure is 1 bar. Juno's mission, launched in August 2011, aims to reduce the uncertainty of these parameters, thereby achieving progress in modeling the interior of Jupiter.

The kernel is surrounded by dense metallic hydrogen that extends outward to about 78% of the planet's radius. Drops of helium and neon droplets deep into the planet through this layer, impoverish the upper atmosphere of Jupiter in these elements.

Above the layer of metallic hydrogen there is a transparent inner atmosphere in which liquid and hydrogen gas is found; the gas layer extends from the cloud base to a depth of about 1000 km. Instead of a clear boundary or surface between the various hydrogen phases, the gas probably flows smoothly into the liquid. This is the case when the temperature is above the critical temperature of the substance, which is equal to 33 K for hydrogen.

The temperature and pressure of the interior increases with depth. In the phase transition area where liquid hydrogen - heated above the critical point - becomes metallic, it is estimated that the temperature reaches 10,000 K and the pressure is 200 GPa. The temperature at the kernel border is estimated at 36000 K, and the pressure at 3000-4500 GPa.

Jupiter has a weak ring system, consisting of three main segments: an internal torus of molecules called halo, a relatively bright main ring, and an outer openwork ring. These rings seem to be made of dust, not ice, like Saturn's rings. The main ring is probably built of material ejected as a result of micrometeorite impacts from the moons of Adrastei and Metis. Instead of falling back to the moon, the material goes into orbit around Jupiter because of the strong influence of its gravity. Trajectories of ejected particles bring them to Jupiter, and new material is added by successive impacts. In a similar way, the moons of Tebe and Amaltea probably produce two outer rings of openwork. There is also evidence of the existence of a band of rocky particles in the Amaltei orbit,

The magnetic field of Jupiter is 14 times stronger than the terrestrial field, reaching values ​​from 0.42 mT (4.2 gauss) on the equator to 1.0-1.4 mT (10-14 Gs) at the poles. It is the strongest natural magnetic field in the solar system (with the exception of sunspots). It is believed that the magnetic field of Jupiter is generated by eddy currents - swirls in the flow of conductive materials - inside the metallic hydrogen sheath.

The field, forming a large magnetosphere outside the planet, retains the ionized particles of the solar wind. Electrons from the plasma trapped in the magnetosphere ionize the sulfur dioxide supplied by volcanic activity on the moon Io, forming a torus-shaped cloud around the planet. The magnetosphere also traps hydrogen molecules from the atmosphere of Jupiter. The electrons in the magnetosphere generate radio noise in the range of 0.6-30 MHz.

At a distance of about 75 Jupiter's rays from the planet, the interaction of the magnetosphere and the solar wind creates an arcing shockwave. The distance of Jupiter's magnetopauce towards the Sun is subject to fluctuations caused by changes in solar wind pressure. The magnetopause creates the inner edge of the magnetic mantle, where the magnetic field of the planet becomes weak and unorganized. The solar wind has a strong influence on the shape of this region, causing the magnetosphere to lengthen on the "leeward" side of Jupiter creating a "magnetic tail" that reaches almost the orbit of Saturn. The orbits of Jupiter's four largest moons are within the magnetosphere that protects them from the solar wind and simultaneously bombards their surface with high-energy plasma.

The magnetosphere is the cause of emission of radio waves from the vicinity of Jupiter's poles. This process begins when, due to volcanic activity Io, the gases that form the torus around the planet are introduced into the Jupiter magnetosphere. The movement of the moon through this torus causes the formation of the Alfvén waves, which carry the ionized matter into the vicinity of Jupiter's poles. As a result, radio waves are generated as cyclotron radiation, and energy is emitted along the conical surface. When the Earth crosses this cone, the intensity of radio waves from Jupiter may exceed the intensity of the waves of solar emission.

The orbits of Io, Europa and Ganymede, which is the largest satellite in the Solar System, show the commensurability known as the Laplace resonance; for Jupiter's four laps, Io is exactly two laps of Europe and exactly one lap of Ganymede. This resonance causes the gravity of these three large moons to deform their orbits, seeking to give them a more elliptical shape (to increase the eccentricity), because each moon is additionally attracted by the neighbors in the same orbit around each lap. On the other hand, tidal forces from Jupiter aim to give their orbes a circular shape (decrease eccentricity).

The eccentricity of the orbits of Galilean moons causes regular deformations of the shape of the three moons, the gravity of Jupiter stretches them during the approach, allowing them to return to a more spherical shape when the moon moves away from the planet. This tidal stretching warms the inside of the moons through friction. This is most clearly seen on the example of the extremely intense volcanic activity of Io (the most internal moon that is subject to the strongest tidal forces), and to a lesser extent on the geologically young surface of Europe (which indicates a relatively recent renewal of the moon surface by tectonic activity).

Since 1973, several space probes have made a trip around the planet, approaching a distance convenient for observing Jupiter. The Pioneer program brought the first pictures of the atmosphere of the planet and its several moons. It was found that the radiation near the planet was much stronger than expected, but both probes managed to survive in this environment. The probe trajectory measurements were used to improve the accuracy of the Jupiter mass determination. The obscuring of radio signals by the planet helped to better define the diameter of Jupiter and its flattening.

Six years later, Voyager made much better pictures of Jupiter's moons and discovered the system of his rings. The Great Red Spot turned out to be a huge permanent anticyclone. The comparison showed that the Red Spot has changed color since the Pioneer mission - from orange to dark brown. A stream of ionized atoms in orbit was found, and traces of volcanic eruptions were found on its surface; some of them were even active during the mission. During the flight, Voyager flew over the nocturnal, invisible side of the planet, watching the lightning in the atmosphere.

The next mission sent to Jupiter was the Ulysses spacecraft, she used the gravity maneuver near Jupiter to reach the orbit around the Sun. During this trip, the probe conducted research on Jupiter's magnetosphere. However, Ulysses does not have cameras and can not take pictures. The second flight took place twelve years later, at a much greater distance from the planet.

In 2000, the Cassini spacecraft, on the way to Saturn, flew near Jupiter and gave some of the best pictures of the highest resolution in the history of the planet's research. On December 19, 2000, the probe photographed Himalia's moon, but the resolution was too low to reveal any surface details.

The New Horizons spacecraft flew close to Jupiter on the way to Pluto, observing the planet, its moons and rings. The largest approximation was made on February 28, 2007. The probe sensors measured plasma production from volcanoes on Io; the probe examined all four galilean moons, and watched the outer moons: Himalia and Elara from a distance. Photographing the Jupiter system began on September 4, 2006.