Here's why:
* Orbital Period: Neptune has the longest orbital period of all the planets in our solar system, taking approximately 165 Earth years to complete one orbit around the Sun.
* Orbital Velocity: Because of its large distance from the Sun, Neptune's orbital velocity (speed) is relatively slow.
The further a planet is from the Sun, the slower its orbital velocity. This is due to the inverse square law of gravity - the force of gravity weakens with distance.
