It will be the first time that anything created by humans will visit the planet. Voyager will be completing its grand tour of the outer planets that has taken it 12 years to accomplish. In that time it traveled 3 billion miles, passing by and studying Jupiter, Saturn, and Uranus before completing its mission by visiting Neptune. It will make thousands of measurements and take many close-up photos of the planet. It was a long trip.
Earth is the third planet from the sun.
Neptune is the ninth and farthest planet. Now you may have heard that Pluto is the farthest planet, but that's not exactly true right now. Pluto has a very eccentric orbit that occasionally takes it inside the orbit of Neptune. Since 1976 and stretching until 1999, Neptune is the farthest planet from the sun. Neptune is generally hard to find because it's so faint and far away.