The most prominent feature on Jupiter is a storm called the Giant Red Spot. The most recent Hubble observations measure the spot to be about 16,500 km across. That’s the smallest ever measured by Hubble and big decrease from the 23,300 km measured by the Voyager 1 and Voyager 2 flybys in 1979. Telescopic observations during the 19th-century indicated a width of about 41,000 lm on its long axis. Current indications are that the rate of shrinking is increasing for the long-lived storm.
Image Credit: NASA