It ’s been around for centuries , but Jupiter ’s Great Red Spot is shrink , and doing so at an speed rate . Astronomers can still impress people by talking of a single storm larger than the whole Earth , but perhaps not for much longer .
The Great Red Spot persist the largest tempest in the solar organization . It is a high air pressure ( anticyclonic ) storm organization at latitude 22 ° in Jupiter ’s southern hemisphere . How long it is has been there no one knows , but something exchangeable was described by Cassini in 1665 and even Galileo thought he insure something that might have been a predecessor . A century ago it adulterate roughly 40,000 km east to west and 14,000 km north - south . The Union - south axis has n’t shift all that much , but the long axis is now16,500kmlong leading to suggestion the spot will presently be round ,
For most of its account the spot has been useful as a timing gadget to see when it crosses Jupiter ’s sharpness or midpoint , and a room for amateurs to test out the capacity of their telescopes , but its nature was mysterious . The Voyager Spacecraft give us much more sixth sense into the nature of Jupiter ’s weather , and told us the Spot iscolder and 8 km higherthan the surrounding clouds , but we still have very trivial mind what is causing it . Even the source of the color is a enigma , with hypothesis including phosphorus and complex constituent compounds . To add to the mental confusion , the distinctive swarm cover that gives the Spot its name does not just coincide with the vortex that causes it or any feature .
likewise , the Spot ’s survival remains unexplained – nowhere else in the solar system do storm last anywhere near this long . On Earth the comportment of continents tend to be disruptive , but storms alsocome and goon the other gaseous state giants with nothing like the same staying power . pocket-size topographic point on Jupiter risen and vanish , most in the summer hemisphere . The next longest durable storm observed has racked up 80 twelvemonth , but in that time modify from white to red , meanwhile the Great Red Spot rolls on .
However , that does n’t stand for it will be here evermore . There has been evidence of smear shrinkage since the 1950s , but the charge per unit is not unceasing . of late it accelerated . In the decade finishing 2006 the Spot lost15 % of its long axis length , The Spot ’s rotation , once occurring around every 6 Earth days , seem to have slacken . inexpert stargazer have been reporting faster shrinkage for some years , but NASA give some of the Hubble Space Telescope ’s cute clock time to a more accurate measurement .
" In our new observations it is manifest that very small Eddy are feed into the tempest , " articulate NASA ’s Dr Amy Simon . " We hypothesized that these may be responsible for the accelerated change by altering the internal dynamics and energy of the Great Red Spot . "
The spot and other Jovinian feature are discussed by NASA scientists here :
