To simplify things the only two objects that matter when it comes to gravity in the solar system is Jupiter and the Sun.
Jupiter is made up from the same stuff as the sun, just less of it. If the sun wasn’t so selfish when it was first gathering in all of the gasses for itself then it would be possible that Jupiter could have reached the tipping point of becoming a Star itself, although that surely would have meant no life on Earth.
We’re not sure if Jupiter has a solid core, but the space craft Juno will be heading there to solve that.
Galilean moons (Jupiters moons)
When Gallileo found these moons it was the first piece of evidence he used to prove that Earth weren’t the centre of the universe.
Io is the most active volcano in the solar system, due to the pull of jupiter (up to 20 concurrent eruptions).
Ganymede is the largest of moons (it’s bigger than Mercury actually).
Jupiter has rings. Yay! All 4 gas planets do.
A comet passed too close to jupiter and was ripped apart. This was ripped into 23 pieces…. which then smashed into jupiter.