why does Jupiter spin so fast while it's so huge
Law of conservation of angular momentum.
It is not much different than Saturn.
Jupiter's fast spin is indeed an interesting aspect considering its enormous size. The reason behind this can be explained by the law of conservation of angular momentum.
Angular momentum is a property of rotating objects and can be understood as the measure of how fast an object is spinning and how spread out its mass is. According to the law of conservation of angular momentum, the total angular momentum of a system remains constant unless acted upon by an external force.
In the case of Jupiter, when it was formed billions of years ago, it started as a large cloud of gas and dust. As gravity caused this cloud to collapse, it began to spin faster due to the conservation of angular momentum. The collapse caused the cloud to contract, resulting in a smaller radius and hence the mass was distributed further from the axis of rotation.
To better understand this, imagine an ice-skater spinning with her arms outstretched. As she pulls her arms closer to her body, the rotational speed increases due to the conservation of angular momentum. Similarly, as Jupiter contracted under its own gravity, its rotation speed increased.
The same principle applies to Saturn as well. It is worth noting that Jupiter's fast spin and its immense size are not directly related. While its large size might lead one to expect a slower rotation, it is the initial conditions during its formation and the conservation of angular momentum that determine its rotational speed.