A year on Neptune, which is the eighth planet from the Sun, lasts approximately 165 Earth years. This long duration is due to Neptune’s significant distance from the Sun, which means it takes a longer time for the planet to complete its orbit.
Neptune orbits the Sun at an average distance of about 30 astronomical units (AU). One AU is the average distance from the Earth to the Sun, roughly 93 million miles or about 150 million kilometers. Because it travels a much larger orbital path compared to planets that are closer to the Sun, the time it takes Neptune to make one full orbit is extended.
Additionally, Neptune’s orbit is slightly elliptical, but this shape does not significantly reduce the overall time it takes to orbit the Sun. To put this in perspective, while we experience an Earth year in 365 days, Neptune’s year stretches over 60,000 Earth days, highlighting the vast differences in time scales across the solar system.