New images of infrared radiation from the Great Red Spot on Jupiter have proven food for thought for astronomers. The images were taken by the eight metre Very Large Telescope’s Imager and Spectrometre for far Infrared – or VISIR instrument in Chile and augmented with data from Gemini South in Chile and the Subaru Telescope in Hawaii. Further data from the Galileo satellite mission to Jupiter in the 90s and the three metre NASA Infrared Telescope Facility in Hawaii have produced an infrared dataset that is now comparable to the visible light record provided by Hubble.
The observations have provided a solid link between temperature and the colour of the GRS. The red core and outer circle of the spot correspond to regions 3-4 degrees Kelvin warmer than the frigid (110K) weather system between them. The astronomers also used aerosols and ammonia to track wind systems in three dimensions, showing that despite turbulence, the system, which is three times the diameter of the Earth, is stable. However, the warmer bits allow the central core to affect a weak clockwise rotation, while the outer region rotates anti-clockwise.
Jupiter’s great red spot has been studied on and off for centuries and continuous observation of its size and shape has been ongoing since the nineteenth century.
The paper produced by this study will be in the next issue of the journal Icarus.