Where does Jupiter's attraction come from?

Although humans have obtained partial data on Jupiter and the moons and ring systems that surround it, many unanswered questions remain. For example, in 2018 U.S. scientists claimed to have discovered 12 moons of Jupiter, bringing the total number of Jupiter's moons to 79, eclipsing the other planets in our solar system. Where does Jupiter's enormous attraction to moons come from?

　　Bigger: the big brother of the solar system planets

　　Before answering this question, it is important to understand where Jupiter came from.

　　Planets originate in the disk of matter. Small particles of dust in the disk clump together to form clumps, called "starlets," which collide with each other to form larger clumps. The larger the clump, the stronger the gravitational pull, and the more gas there is around it, the faster it can "grow". At this point, other small starlets can only "stare" if they want to get bigger, because there is no more gas around to attract them. Jupiter is the "big brother" of the solar system planets in terms of "size" and mass.

　　Charming: the master of capturing moons

　　Jupiter's mass is the basis for its harem of 79 "beauties".

　　Satellites of planets can be fragments of planets that fly away from themselves after an impact, or they can be stars from outer space that are captured by the planet's gravity as they orbit near the planet and become satellites. The moons of Jupiter are no exception. The more massive a planet is, the more massive and denser the planetary disk around it when it forms, and the greater the chance for larger moons to form. More massive planets are more attractive and more likely to attract other objects to their vicinity, while the higher density of debris or gas disks around massive planets provides a more effective "deceleration brake" effect, making it easier to capture moons.

　　To bind the outer moons around the planet, some angular momentum or orbital energy has to be used up, and this process requires some friction. This interaction is what we call the deceleration mechanism. The more massive the planet's perihelion, the stronger the deceleration effect.

　　On balance, the high mass of Jupiter makes its planetary disk denser and more massive, which facilitates the formation of regular satellites; also because of its mass, Jupiter is more likely to capture irregular satellites through the deceleration mechanism.

　　Good luck: a "feeding zone" far from the Sun

　　Jupiter's large size predisposes it to a strong attraction, but even Jupiter's ability to capture is no match for the Sun.

　　However, Jupiter is far from the Sun, so the surrounding material is not easily "abducted" by the Sun. It is worth mentioning that without Jupiter, the Earth, known as the "miracle star," would not have survived, because the likelihood of a meteorite hitting the Earth would have increased more than 1,000 times.

　　In contrast to Jupiter, Earth-like planets such as Mercury and Venus are very close to the Sun. "The last stage of Earth-like planet formation is the formation of several 'planetary embryos' that collide and merge with each other in the inner solar system. This is a relatively 'violent' process in which the planets are in a very unstable environment and have difficulty preserving their moons. That's why Earth-like planets rarely have moons." Zhou Liyong said.

　　But Kong Dali has a different view. "After the formation of the solar system, the material in the solar system will basically not be sucked away by the sun anymore. Even if it's a black hole with a strong gravitational force, a bunch of matter around it will not fall inside the black hole. Unless this rotating matter is slowed down by some mechanism, it is possible to fall down. Also, there are planetary systems where planets like Jupiter are very close to the star. So the fact that Jupiter has a lot of moons doesn't have a lot to do with its distance from the sun."

　　"There is no reason for many phenomena in the universe, and nature cannot develop without luck. It is not surprising that Jupiter's naturally large mass determines that it has many moons." Kong Dali said astronomers are concerned about the discovery of new moons around Jupiter because under the original observation conditions, very small and faint moons are very difficult to detect. "If new small moons are found, it means the level of observation has improved."

　　In Kong Dali's opinion, one more or one less satellite of Jupiter does not defy common sense. With more mass and more gravity, there is naturally more material around. It would be strange if a planet as small as Mercury had dozens of moons around it.