The spot is probably an enormous, rotating storm, like Jupiter's long-standing Great Red Spot, Neptune's Great Dark Spot
, and Saturn's Great White Spots.
We've grown familiar with them, from Mercury with its shriveled surface to Neptune with its Great Dark Spot
August 1989 Voyager 2 remains the only spacecraft to visit the windiest planet in the solar system: Near the Great Dark Spot
, hurricane winds rage over 2,000 km (1,500 mi) per hour.
In 1989, Voyager flew past Neptune and spied another storm, dubbed the Great Dark Spot
because of its appearance in visible light.
Dubbed the Great Dark Spot
by planetary scientists, this feature was assumed to be more or less permanent, like Jupiter's Great Red Spot.
Like Jupiter, with its Great Red Spot, Neptune has an especially turbulent atmospheric storm-as large in diameter as the planet Earth-that scientists have dubbed the Great Dark Spot
That first year, they were astonished to find that Neptune's Great Dark Spot
, the dominant feature seen by the Voyager spacecraft, had vanished (SN: 10/30/93, p.
Dominating the Voyager images is a murky oval dubbed the Great Dark Spot
(GDS), as well as smaller Dark Spot 2 (DS2).
New images of Neptune revealed that the planet's Great Dark Spot
has vanished (146: 312).
Both sets of images confirm that Neptune's Great Dark Spot
-- a major storm feature seen by Voyager 2 -- has vanished.
We hope to glimpse the Great Dark Spot
but do not see it.
Voyager 2 had discovered several large features, such as the Great Dark Spot
, a counterclockwise storm about the size of Earth.