Jupiter's Famous Red Spot Has Shrunk To Its Smallest Size Ever Observed

New images from the Hubble Telescope suggest that Jupiter's iconic red spot has shrunk to the smallest size on record. The red spot, which is actually a giant storm that has been raging through the planet's atmosphere for centuries. The latest measurements place the storm at roughly 10,250 miles wide, but while that might sound pretty large, it's actually more than half the size of measurements taken back in the 1800's which estimated the storm to measure around 25,500 miles across.

When the two Voyager spacecraft flew by the planet in 1979, the storm clocked in at 14,500 miles wide, while observations in 2009 gauged it at around 11,100 miles across. However, since 2012, research suggests that Jupiter's trademark red spot has been shrinking at a rate of almost 600 miles per year, becoming more circular as it does so. Quite what is behind this transformation has not been confirmed, but NASA researchers have theorized that it may be slowing down due to an as yet unidentified change in the planet's atmosphere.

"In our new observations it is apparent very small eddies are feeding into the storm," said NASA's Amy Simon. "We hypothesized these may be responsible for the accelerated change by altering the internal dynamics and energy of the Great Red Spot."

The massive storm is thought to have been first observed by the great astronomer Giovanni Cassini in the mid 17th century. The storm circumnavigates Jupiter's southern hemisphere generating winds of up to 425 miles per hour.

For more images and commentary on this story, visit Hubblesite.org. The Hubble team will be hosting a live web chat to discuss the mystery on May 22nd at 4pm EST. You can join the debate here.