Jupiter's Great Dark Spot

Jupiter's Great Dark Spot



Seventeenth century astronome Giovanni Domenico Cassini wasan astute observer of Jupiter's Great Red Spot.So it seems only fitting that his namesake, the Cassini spacecraft,has enabled detailed observations of another planet-sizedblemish -- Jupiter' Great Dark Spot.Unlike the Red Spot, the Great Dark Spot lies nea Jupiter's north poleand seems to appear and disappear over periodsof months rather than persisting for hundreds of years.Seen at ultraviolet wavelengths, the dark featureresides in the Jovian stratosphereconfined by pole-encircling winds, analogous to planet Earth'santarctic ozone hole.This image of the Dark Spot is a single frame from moviecreated wit datarecorded during the spacecraft's year 2000 flyby of Jupiter.Projected to show Jupiter's north polar region, no data are availablefor the blank central area, while the Great Dark Spot liesabove and just left of center.The white circle marks 60 degrees latitude andthe blue contour outlines a persisten Jovian auroral zonewhich may be related to the formation of the Great Dark Spot.