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Great Red Spot II

August 19, 2014

Jupiter’s Great Red Spot may have been around for centuries. Yet during that long span it’s been anything but steady. It wiggles back and forth, it changes size, and it even changes color. In fact, just why the Great Red Spot is red is still a puzzler.

The spot is a giant storm. At its peak it was wide enough to swallow three Earths, although it’s been shrinking for decades; more about that tomorrow. Its cloudtops tower several miles above the surrounding layers of clouds in Jupiter’s thick atmosphere. Winds are strongest near its edge, where they race along at hundreds of miles per hour, but quite calm at its center.

Over the decades, the spot’s color has ranged from cherry red to orange to pink. Right now it’s more orange than red, although it still stands out next to the lighter-colored bands of clouds around it.

The leading theory says the color comes from sulfur-rich compounds that the storm dredges up from deep within Jupiter’s atmosphere. As these compounds are pulled to the top of the clouds, ultraviolet radiation from the Sun splits them apart. The sulfur molecules then turn red.

Yet that scenario hasn’t been confirmed. And even if it’s correct, scientists are uncertain just which sulfur compounds the storm plumbs from below, or from what depths it pulls them. It’s also not clear how those compounds are spread out across the storm. So there’s still a lot to learn about Jupiter’s most famous feature.

Script by Damond Benningfield, Copyright 2014


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