The Sept. 9, 2019, opposition event came just after the 30th anniversary of the Voyager 2 flyby of the planet, in 1989. So far the only terrestrial visitor to Neptune, Voyager 2 provided our closest glimpse of the planet, passing about 3,000 miles (5,000 kilometers) above its north pole, while also spotting six undiscovered moons and confirming the existence of faint rings around Neptune. The pictures Voyager 2 sent back gave scientists a new snapshot of weather in the extreme, including a dark and violent vortex that looked similar to the Great Red Spot on Jupiter. Since then, observatories such as the Hubble Space Telescope and James Webb Space Telescope have given us additional views of the planet from afar. NASA scientists have learned, for instance, that unlike Jupiter, the Neptune vortex disappears for a time, and then similar storms appear later. Scientists have determined that Neptune has seasons such as those on Earth, but that these are much longer, spanning decades instead of months. By studying these seasons on a continual basis, scientists look to gain a better understanding of the similarities and differences of atmospheres on other planets, including right here on Earth.
