jupiters moons

[Lydia]

Hi, I'm new to astronomy. I'll probably be asking lots of questions! My first question is: How did Jupiter and Saturn get rock moons when they're gas giants? How did their moons form?

[David Frydman]

Hi Lydia and welcome.

A good question.
I don't know the answer, but with a lot of material one probably ends up with a gas outer part and maybe metal? solid inner core.

With a small amount of material, more likely solid outer part.

But the Earth has I think a molten inner core.

So maybe the answer is just gravitational forces.
For larger or smaller amounts of material.

As I said, I don't really know.

Regards,
David

[LeoLion]

There is a fairly comprehensive explanation here https://en.wikipedia.org/wiki/Moons_of_ ... _evolution . Finding that and so familiar with the four Gallileons (spelling?) there are now seventy nine .Hope the wiki helps (its wised me up too).
Re the Saturnian moons look here https://en.wikipedia.org/wiki/Moons_of_Saturn#Formation

[brian livesey]

Some of the smaller moons are captured asteroids and comet nuclei.

[skyhawk]

https://www.space.com/48-saturn-the-sol ... bearer.htm

As the most massive planet in the solar system after Jupiter, the pull of Saturn's gravity has helped shape the fate of our system. It may have helped violently hurl Neptune and Uranus outward. It, along with Jupiter, might also have slung a barrage of debris toward the inner planets early in the system's history

[skyhawk]

Some of the smaller moons are captured asteroids and comet nuclei.

Perhaps

[brian livesey]

We can only wonder how long the planets will retain their present resonance.