"This is our first detailed look inside the biggest storm of the Solar System," says Glenn Orton, who led the team of astronomers（天文学家） that made the study. "We once thought the Great Red Spot（木星表面大红斑） was a plain old oval（椭圆形，卵形） without much structure, but these new results show that it is, in fact, extremely complicated." The observations reveal that the reddest colour of the Great Red Spot corresponds to a warm core within the otherwise cold storm system, and images show dark lanes at the edge of the storm where gases are descending into the deeper regions of the planet. The observations, detailed in a paper appearing in the journal Icarus, give scientists a sense of the circulation patterns（环流模式） within the solar system's best-known storm system.

Sky gazers have been observing the Great Red Spot in one form or another for hundreds of years, with continuous observations of its current shape dating back to the 19th century. The spot, which is a cold region averaging about -160 degrees Celsius, is so wide that about three Earths could fit inside its boundaries.

The thermal images were mostly obtained with the VISIR instrument attached to ESO's Very Large Telescope in Chile, with additional data coming from the Gemini South telescope in Chile and the National Astronomical Observatory of Japan's Subaru Telescope in Hawaii. The images have provided an unprecedented（空前的） level of resolution and extended the coverage provided by NASA's Galileo spacecraft in the late 1990s. Together with observations of the deep cloud structure by the 3-metre NASA Infrared Telescope Facility in Hawaii, the level of thermal detail observed from these giant observatories is for the first time comparable to visible-light images from the NASA/ESA Hubble Space Telescope.

VISIR allows the astronomers to map the temperature, aerosols（气溶胶，喷雾器） and ammonia（氨） within and surrounding the storm. Each of these parameters（参数，参量） tells us how the weather and circulation patterns change within the storm, both spatially（空间地） (in 3D) and with time. The years of VISIR observations, coupled with those from the other observatories, reveals how the storm is incredibly stable despite turbulence（扰动，骚乱） , upheavals（剧变，隆起） and close encounters with other anticyclones（反气旋，高气压） that affect the edge of the storm system.

"One of the most intriguing（迷人的，有趣的） findings shows the most intense orange-red central part of the spot is about 3 to 4 degrees warmer than the environment around it," says lead author Leigh Fletcher. This temperature difference might not seem like a lot, but it is enough to allow the storm circulation, usually counter-clockwise（逆时针方向的） , to shift to a weak clockwise circulation in the very middle of the storm. Not only that, but on other parts of Jupiter, the temperature change is enough to alter wind velocities（风速，风矢量） and affect cloud patterns in the belts and zones.

"This is the first time we can say that there's an intimate（亲密的，精通的） link between environmental conditions — temperature, winds, pressure and composition — and the actual colour of the Great Red Spot," says Fletcher. "Although we can speculate（推测，思索） , we still don't know for sure which chemicals or processes are causing that deep red colour, but we do know now that it is related to changes in the environmental conditions right in the heart of the storm."