SCIENCE / MEDICINE : Jupiter’s Red Spot Is Getting Redder

Jupiter’s Great Red Spot is getting redder, following a color change by a 6,200-mile-wide belt of clouds, scientists said as NASA prepares for the Galileo’s six-year mission to the planet.

“This is a dynamical, neat place to look at. It’s changing and doing wild things on a huge scale,” said Rita Beebe, an astronomer at New Mexico State University.

British astronomer G. M. Hurst on July 16 first noticed that Jupiter’s 6,200-mile-wide Southern Equatorial Belt was changing from brown to white.

Since then, the Great Red Spot--a hurricane almost twice Earth’s size that faded to dim gray in 1976--has been returning gradually to its brick red color, Beebe said last week.

“The Red Spot appears to be darkening. Color seems to be coming back,” said Stephen O’Meara, an associate editor at Sky & Telescope magazine in Cambridge, Mass. “Some observe it as orange; some pink. It has a pale luster.”

The Great Red Spot, which is at least 350 years old and measures about 12,400 miles east to west and 6,200 miles north to south, is continuing to get redder and about six months from now “will settle down as a beautiful oval red spot,” Beebe said.

The darkening is being caused by the changing color of the Southern Equatorial Belt, which sits just north of the spot, she said.