Jovian Storms Forecast for Fourth of July

Forget hurricane season. The really big storms to watch this summer are out of this world.

Specifically, they’re on Jupiter, where the Great Red Spot– a massive, centuries-old storm of 350 mph winds that is twice as big as the Earth — and Oval BA, aka "Red Jr.," — a six-year-old storm that is "only" the size of one Measly earth — are expected to brush against each other on or about the Fourth of July. Fireworks may fly, reports:

 "There won’t be a head-on collision," [says Amy Simon-Miller, an astronomer at Goddard Space Flight Center in Maryland.] "The Great Red Spot is not going to ‘eat’ Oval BA or anything like that."

However, the storms’ outer bands are expected to pass close to one another and it’s anybody’s guess what will happen when they do.

This isn’t the first time that such an encounter has happened. In fact, the two storms typically pass each other every two years or so. Similar encounters happened in 2002 and 2004, but they were very anti-climactic. Aside from some "roughing" around the edges, both storms came out unscathed.

This time might be different, however, said Simon-Miller. Red Jr. could revert to its original color and change from red to white. From 2000 to 2005, Red Jr. was actually white and no different form the many other small "white ovals" circling the planet.

But in 2006, astronomers noticed a change: a red vortex formed inside the storm, the same color as the powerful Great Red Spot. Scientists believe the color change was a sign that the storm was intensifying.

Scientists think the Great Red Spot could push Oval BA toward a southern jet stream on the planet during their upcoming encounter. The jet stream blows against Oval BA’s counterclockwise rotation and could slow its spin, possibly changing the storm’s color back to white.

The color of the Great Red Spot itself is a mystery. According to one popular theory, the storm dredges up material from deep inside Jupiter’s atmosphere, lofting it above the highest clouds where ultraviolet rays from the Sun turn color-changing compounds, called "chromophores," red.