Jupiter's Stormy Great Red Spot is Shrinking More Quickly Than Before

Jupiter's Great Red Spot, the massive anticyclonic storm that churns across the planet's surface, may be shrinking. Using new NASA/ESA Hubble Space Telescope images, scientists have captured the Red Spot at its smallest size to date.

The Great Red Spot is a swirling, violent storm that's larger than Earth itself. Its howling winds scream at a staggering 425 mph at its outer edges. And while it was first recorded in 1831, the storm may have first been discovered in 1665 by early observers.

In the late 1800s, though, scientists estimated that this storm system was about 41,000 kilometers at its widest point; that's wide enough to fit three Earths inside comfortably, side-by-side. Yet then in 1979 and 1980, NASA Voyager fly-bys found that the spot had shrunken to 23,335 kilometers across. And now, it seems as if the spot has shrunk even further.

"Recent Hubble Space Telescope observations confirm that the spot is now just under 16,500 kilometers across, the smallest diameter we've ever measured," said Amy Simon of NASA's Goddard Space Flight Center in a news release. "In our new observations it is apparent that very small eddies are feeding into the storm. We hypothesized that these may be responsible for the accelerated change by altering the internal dynamics of the Great Red Spot."

In 2012, amateur astronomers noticed an acceleration in the spot's shrinkage rate. The massive storm was getting smaller by just under 1,000 kilometers per year. While the reason for this fast shrink is unknown, though, researchers plan to study it a bit further.

Simon and her team are aiming to study the motions of the eddies seen feeding into the storm. They will also examine the internal dynamics of the spot in order to find out how the storm vortex is fed with or sapped of momentum. This, in turn, should reveal a few more answers when it comes to why Jupiter's most defining feature is rapidly disappearing.