NASA https://solarsystem.nasa.gov/planets/neptune/indepth Neptune: In Depth it takes it 165 years to make a single pass http://solarsystem.nasa.gov/planets/neptune/indepth says NASA http://solarsystem.nasa.gov/planets/neptune/indepth Neptune: In Depth NASA NASA NASA NASA NASA says NASA http://solarsystem.nasa.gov/planets/neptune/indepth NASA ottavo pianeta NASA NASA NASA it takes it 165 years to make a single pass NASA