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Two of Jupiter's largest storms are visible; the Great Red Spot on the western (left) limb of the planet, trailing the Little Red Spot on the eastern limb, at slightly lower latitude. The Great Red Spot is a 300-year old storm more than twice the size of Earth. The Little Red Spot, which formed over the past decade from the merging of three smaller storms, is about half the size of its older and "greater" counterpart.
From New Horizons website
Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute