Answer :
Final answer:
Neptune's orbital period is 165 years, completing its journey around the Sun much more slowly than inner planets due to its greater distance.
Explanation:
The orbital period of Neptune is 165 years. This is the time it takes for Neptune to complete one full orbit around the Sun. Given its significant distance from the Sun, at 4.5 x 10⁹ km, Neptune moves with an average orbital speed of only about 5 kilometers per second, which is much slower in comparison to the inner planets like Mercury, which travels at an average speed of 48 kilometers per second with an orbital period of 88 Earth-days.
