In just 3 days, NASA’s Juno spacecraft will fly directly over Jupiter’s Great Red Spot, a 10,000-mile-wide (16,000 km) storm that’s been whirling around the atmosphere for possibly 400 years or more. While the Voyager and Galileo spacecraft have taken photos of the planet’s most iconic feature, Juno will come closer than any before it, flying just 5,600 miles (9,000 km) above the Spot on July 10.
“Jupiter’s mysterious Great Red Spot is probably the best-known feature of Jupiter,” said Scott Bolton, principal investigator of Juno. “This monumental storm has raged on the solar system’s biggest planet for centuries. Now, Juno and her cloud-penetrating science instruments will dive in to see how deep the roots of this storm go, and help us understand how this giant storm works and what makes it so special.”
This will be Juno’s sixth science flyby of Jupiter. It will reach perijove, its closest to the planet, Monday, July 10 at 8:55 p.m. CDT when it zooms just 2,200 miles (3,500 km) above the cloud tops. 11½ minutes later it will cruise directly over the Great Red Spot. All eight of the spacecraft’s instruments as well as its imager, JunoCam, will be on during the flyby.
Back in May, the Gemini North telescope on Mauna Kea on the big island of Hawaii took high-resolution photos of Jupiter in different infrared colors (wavelengths) of light to support the Juno mission and uncovered a curious swirling structure in the Spot’s inside, a hook-like feature on its western side and a beautiful, feathery wave extending off its eastern side.
The Gemini telescope uses special filters that detect specific colors of light than can penetrate the upper atmosphere and clouds of Jupiter. It also uses advanced “adaptive optics” to remove distortions from turbulence in the Earth’s atmosphere and produce extremely high-resolution images. In adaptive optics, the telescope’s main mirror is continually flexed as if were a rubber sheet (it’s not, it’s glass but still flexible) to compensate for the turbulence in the air that would otherwise distort and blur objects photographed through the telescope.
It’s an amazing image and reminds us that each color of light unpeels a new layer of Jovian surprises. Stay tuned for more next week.