Let s take a look at the more famous moons of the solar system

Ganymede. Ganymede is the largest moon in the solar system, larger in diameter than Mercury but half as massive. Ganymede is much larger than Pluto.

Ganymede was discovered by Galileo and Marius in 1610. But in fact, as early as more than 2,000 years ago, the famous astronomer Gander of Chu during the Warring States period of China discovered it, but because science was not widely popularized at that time, this conclusion was considered a fallacy. It was not until the discovery of Galileo in 1610 that this claim was confirmed.

Researchers have discovered that beneath the rugged ice on the surface of Ganymede, the largest moon in the solar system, there may be a liquid saltwater ocean. The presence of underground water sources is an important indicator of whether there are signs of life on the planet. This latest result makes Ganimide also the third Jupiter moon to have an underground water source.

Two other similar moons are Europa and Callisto. The researchers discovered a possible subterranean ocean while analyzing data from NASA's Galileo spacecraft. After the launch of the Galileo spacecraft in December 1995, it began orbiting Jupiter to collect data.

On May 20 of this year, Galileo finally flew to the closest position to "Ganimed", which was only 809 kilometers apart. Scientists' most recent discoveries are based on the information that has been transmitted back this time. According to the research team, a device used to test the magnetic field detected subtle changes inside Ganimide, suggesting that it may be a conductive liquid, such as salt water.

Margaret Kivelson, a space physicist at the University of California, Los Angeles (UCLA), said: "After months of battling with a huge amount of data, we believe that there should be a layer of liquid water hidden under the surface ice of Ganimede. The layer, which is several miles thick, is supposed to be about 160 kilometers below the satellite's surface, and the water temperature may be minus below zero, but it is not frozen because of the high pressure inside the satellite, Kiferson said.

Researchers associated with Galileo also said that based on the spacecraft's recent altitude development**, the surface activity of Ganimide appears to be similar to that of Earth. Affected by the heat of the radioactive elements inside the satellite, the hard ice on the surface of Ganimide is, in fact, floating on a layer of more active ice. However, in the human search for extraterrestrial creatures, Jupiter's "Europa" moon is still the main goal of the scientific community.

Because, unlike Callisto or Ganimede, the layers of the ocean that scientists have detected on Europa are not very deep, only a few miles from the surface.

Titan. Similar to the early Earth.

The controversial first largest moon of the solar system. There is also information that Europa is the largest. In addition, Titan is the only moon with an atmosphere, and its surface environment is similar to that of Earth 3.9 billion years ago, when life first formed.

The solar system consists of the Sun, nine planets, 64 planetary moons, a large number of small stars (comets and asteroids), and an interplanetary medium. The inner layers of the solar system contain the Sun, Mercury, Venus, Earth, Mars:

The outer planets are Jupiter, Saturn, Uranus, Neptune and Pluto

The main ones are the moons of Jupiter and Saturn, mainly due to the fact that they are more similar to the Earth, and there is a possibility of life.

Moon, do you need an explanation?

Keiso Kibashi is the largest moon in the solar system. With a diameter larger than Mercury and a mass about half that of Mercury, Europa is composed mainly of silicate rocks and ice, with distinct stratification and an iron-rich, fluid core. It is larger than Mercury and is the only known moon in the solar system that has a magnetosphere.

Ganymede is the only known moon in the solar system to have a magnetosphere, which may have been created by the convective motion of an iron-rich flowing core. A small number of these magnetospheres overlap with Jupiter's larger magnetic field, creating field lines that spread outward.

Mu Weiyou lost three.

The largest known moon in the solar system is Jupiter's moon Europa, which has an average radius of 2,631 kilometers, or 5,262 kilometers in diameter, and is larger than Mercury, which is only 4,878 kilometers in diameter.

Among the known moons in the solar system, the second to fifth largest are Titan, which is 5,151 kilometers in diameter, Calmede in diameter 4,820 kilometers, Europa in diameter 3,642 kilometers, and the Moon in diameter, which is 3,476 kilometers in diameter. The size of Europa is not much different from that of Mars, which is only one lap smaller than Mars at 6,794 kilometers in diameter.

Features of Europa.

Europa orbits Jupiter rapidly, the orbital period is about 7 days, and Europa ranks seventh in distance from Jupiter among Jupiter's moons, although Ganymede is larger in diameter than Mercury, but its mass is only about half that of Mercury, which means that the density of Ganymede is much smaller than that of Mercury.

Callista is mainly composed of silicates and ice, and its surface is covered with hundreds of kilometers of hard ice that is difficult for even a meteorite impact to penetrate. There is a striking bright meteorite crater on the surface of Ganymede, while the white lines that radiate around it remind us of how thick the ice of Ganymede is.