Which planet has the shortest day of any planet in our solar system - only 9 hours and 55 minutes?

Despite being the largest planet, this gas giant has the fastest spin in our solar system, completing one full rotation in just 9 hours and 55 minutes. This rapid spin is a legacy of its formation over 4.5 billion years ago. As the immense cloud of gas and dust that formed the planet collapsed under its own gravity, it spun faster and faster due to the conservation of angular momentum, similar to how an ice skater speeds up when they pull their arms in.

Because it is a gas planet and not a solid body, it doesn't rotate as a single, rigid object. This phenomenon, known as differential rotation, means the planet's equator spins slightly faster than its polar regions. A "day" at the equator is about five minutes shorter than a day near the poles. The commonly cited time is an average based on the rotation of the planet's magnetic field, which is generated by its core.

This furious rotational speed has a noticeable effect on the planet's shape. The powerful centrifugal force causes it to bulge significantly at its equator and flatten at its poles. This makes it an "oblate spheroid" rather than a perfect sphere, a visible consequence of having the shortest day in the solar system.