Amazing Images Show Jupiter's Red Spot Continuing to Shrink

A new flat map of Jupiter produced by images from NASA's Hubble Space Telescope. NASA/ESA/Goddard/UCBerkeley/JPL-Caltech/STScI

Jupiter's famous Great Red Spot continues to shrink, as shown in a series of stunning visuals captured by NASA's Hubble Space Telescope.

These new images and videos reveal several new features as well: a unique "filament" inside the core of the spot, and a rare atmospheric wave just north of the planet's equator that had only been seen once before.

"Every time we look at Jupiter, we get tantalizing hints that something really exciting is going on," said Amy Simon, a planetary scientist at NASA's Goddard Space Flight Center, said in a statement. "This time is no exception."

It's unknown exactly what the filament inside the Giant Red Spot represents, but NASA reports that "this filamentary streamer rotates and twists...getting distorted by winds blowing at 330 miles per hour (150 meters per second) or even greater speeds." What is clear is that the red spot—which is an enormous cyclone similar to a hurricane, but big enough for three Earths to fit inside its boundaries—is getting smaller. The long axis of the formation is about 150 miles (240 kilometers) shorter now than it was in 2014, NASA reports.

The new "wave" pattern, north of the equator and well away from the Giant Red Spot, was seen once, decades earlier, by the spacecraft Voyager 2.

In Jupiter’s North Equatorial Belt, scientists spotted a rare wave that had been seen there only once before. This false-color close-up of Jupiter shows cyclones (arrows) and the wave (vertical lines). NASA/ESA/Goddard/UCBerkeley/JPL-Caltech/STScI

"Until now, we thought the wave seen by Voyager 2 might have been a fluke," said Glenn Orton of NASA's Jet Propulsion Laboratory. "As it turns out, it's just rare!"

It appears to be similar to so-called baroclinic waves on Earth, which sometimes show up in the atmosphere as cyclones form. "The wave may originate in a clear layer beneath the clouds, only becoming visible when it propagates up into the cloud deck," NASA noted.