<P> On February 25, 1979, when the Voyager 1 spacecraft was 9.2 million kilometres (5.7 million miles) from Jupiter it transmitted the first detailed image of the Great Red Spot back to Earth . Cloud details as small as 160 kilometres (100 miles) across were visible . The colorful, wavy cloud pattern seen to the left (west) of the Red Spot is a region of extraordinarily complex and variable wave motion . </P> <P> At the start of 2004, the Great Red Spot had approximately half the longitudinal extent it had a century ago, when it reached a size of 40,000 kilometres . At the present rate of reduction it would become circular by 2040 . It is not known how long the spot will last, or whether the change is a result of normal fluctuations . </P> <P> A smaller spot, designated Oval BA, formed recently (March 2000) from the merger of three white ovals, has turned reddish in color . Astronomers have named it the Little Red Spot or Red, Jr . As of June 5, 2006, the Great Red Spot and Oval BA appeared to be approaching convergence . The storms pass each other about every two years but the passings of 2002 and 2004 were of little significance . Amy Simon - Miller, of the Goddard Space Flight Center, predicted the storms would have their closest passing on July 4, 2006 . She worked with Imke de Pater and Phil Marcus of UC Berkeley, and a team of professional astronomers since April 2006 to study the storms using the Hubble Space Telescope; on July 20, the two storms were photographed passing each other by the Gemini Observatory without converging . In May 2008 a third storm turned red . </P> <P> The Great Red Spot should not be confused with the Great Dark Spot, a feature observed near the northern pole of Jupiter in 2000 with the Cassini--Huygens spacecraft . Note that a feature in the atmosphere of Neptune was also called the Great Dark Spot . The latter feature was imaged by Voyager 2 in 1989, and may have been an atmospheric hole rather than a storm and it was no longer present as of 1994 (although a similar spot had appeared farther to the north). </P>

How does the length of the great red spot compare with the diameter of jupiter