La grande macchia di Giove muta il suo comportamento, cosa prepara?
Jupiter's Great Red Spot Is Shrinking
“The velocity data show that the Red Spot has been shrinking along its major diameter by about 15 percent over that period,” said Xylar Asay-Davis, who conducted the study along with Phil Marcus, Mike Wong and Imke de Pader at the University of California at Berkeley.
The finding agrees with other studies of cloud cover, Asay-Davis said, and it puts the conclusion on more solid footing. “Velocity is a more robust measurement because the clouds associated with the Red Spot are also strongly influenced by numerous other phenomena in the surrounding atmosphere,” he said.
It's not clear yet why the storm is shrinking, but after 300 years of hanging in there, the spot is in no danger of disappearing anytime soon, Asay-Davis said. It continues to kick up winds that routinely exceed 300 mph.
“We find that the Red Spot has been shrinking but not slowing down,” Asay-Davis told SPACE.com.
There is a balance of energy flowing in and out of the storm, either as it mixes with the surrounding atmosphere, consumes smaller storms, or when energy is radiated into space, he explained.
“We don't fully understand all the sources of energy, or the ways the Red Spot loses energy, but these can become slightly imbalanced for a period of time, and this is likely to be what is causing the Red Spot to shrink — less energy is being fed in and more is slowly dissipating away,” he said.