The trademark of Jupiter, the Great Red Spot, has shrunk its size from how big it used to be. NASA says it’s the smallest it has been since astronomers started tracking it through their journey for more than a century ago.
Amy Simon of NASA’s Goddard Space Flight Center in Greenbelt, Maryland says, “Recent NASA Hubble Space Telescope observations confirm the Great Red Spot now is approximately 10,250 miles across. Astronomers have followed this downsizing since the 1930s.”
The Great Red Spot is a high pressure anti-cyclonic storm that’s similar to Earth’s hurricane. It was so enormous (25,500 miles wide) back in the late 1800s – the size big enough to fit three Earths within its boundaries. But in 1979, when NASA’s Voyager 1 and Voyager 2 flew by, the spot was estimated to be only 14,500 miles across, and it was further downsized to 13,020 miles across when Hubble took a picture of it in 1995. Another photo taken in 2009 confirmed that it was measured at 11,130 miles wide.
In 2012, the downsizing accelerated at the rate of 580 miles each year, resulting in change of its shape from an oval to a circle.
According to their observations, small eddies feeding into the storm may be responsible for the accelerated change by altering the internal dynamics and energy of the Great Red Spot. However, the actual source of shrinkage is not known.