Juno Sends Back Incredible New Images of Jupiter

NASA’s Juno spacecraft has beamed back the most detailed images yet of the Solar System’s king of the planets, Jupiter.

This montage of ten JunoCam images shows Jupiter growing and shrinking in apparent size before and after Juno made its closest approach on August 27 at 12:50 UTC. The images are spaced about 10 hours apart, one Jupiter day, so the Great Red Spot is always in roughly the same place. The small black spots visible on the planet in some of the images are shadows of the large Galilean moons. The images in the top row were taken during the inbound leg of the orbit, beginning on August 25 at 13:15 UTC when Juno was 1.4 million miles (2.3 million km) away from Jupiter, and continuing to August 27 at 04:45 UTC when the spacecraft was 430,000 miles (700,000 km) away. The images in the bottom row were obtained during the outbound leg of the orbit. They begin on August 28 at 00:45 UTC when Juno was 750,000 miles (920,000 km) away and continue to August 29 at 16:45 UTC when the spacecraft was 1.6 million miles (2.5 million km) away. Image credit: NASA / JPL-Caltech / SwRI / MSSS.

Juno successfully performed its first of 36 close flybys of Jupiter on August 27, 2016, when the spacecraft passed about 2,600 miles (4,200 km) above planet’s swirling clouds.

The download of 6 Mb of data collected during the six-hour transit took 1.5 days. While analysis of the data is ongoing, some unique discoveries have already made themselves visible.

As Juno closed in on Jupiter for the first flyby, its view grew sharper and fine details in the north polar region became increasingly visible. JunoCam obtained this view on August 27, about two hours before closest approach, when the spacecraft was 120,000 miles (195,000 km) away from the gas giant. Unlike the equatorial region’s familiar structure of belts and zones, the poles are mottled with rotating storms of various sizes, similar to giant versions of terrestrial hurricanes. Jupiter’s poles have not been seen from this perspective since NASA’s Pioneer 11 spacecraft flew by the planet in 1974. Image credit: NASA / JPL-Caltech / SwRI / MSSS.

Storm systems and weather activity unlike anything encountered in the Solar System are on view in these images of Jupiter’s north polar region. The two images have been contrast-enhanced differently to bring out detail near the dark terminator and near the bright limb. The images were taken by JunoCam on August 27, when the spacecraft was about 48,000 miles (78,000 km) above the polar cloud tops. A wavy boundary is visible halfway between the grayish region at left (closer to the pole and the nightside shadow) and the lighter-colored area on the right. The wavy appearance of the boundary represents a Rossby wave – a north-south meandering of a predominantly east-west flow in an atmospheric jet. This may be caused by a difference in temperature between air to the north and south of this boundary, as is often the case with such waves in Earth’s atmosphere. The polar region is filled with a variety of discrete atmospheric features. Some of these are ovals, but the larger and brighter features have a ‘pinwheel’ shape reminiscent of the shape of terrestrial hurricanes. Tracking the motion and evolution of these features across multiple orbits will provide clues about the dynamics of the Jovian atmosphere. Image credit: NASA / JPL-Caltech / SwRI / MSSS.

This Juno image provides a never-before-seen perspective on Jupiter’s south pole. JunoCam acquired the view on August 27, when the spacecraft was about 58,700 miles (94,500 km) above the polar region. At this point, the spacecraft was about an hour past its closest approach, and fine detail in the south polar region is clearly resolved. Unlike the equatorial region’s familiar structure of belts and zones, the poles are mottled by clockwise and counterclockwise rotating storms of various sizes, similar to giant versions of terrestrial hurricanes. The south pole has never been seen from this viewpoint, although the Cassini spacecraft was able to observe most of the polar region at highly oblique angles as it flew past Jupiter on its way to Saturn in 2000. Image credit: NASA / JPL-Caltech / SwRI / MSSS.

During the flyby, Juno’s visible-light camera/telescope, called JunoCam, captured the first-ever images of Jupiter’s poles.

“First glimpse of Jupiter’s north pole, and it looks like nothing we have seen or imagined before. It’s bluer in color up there than other parts of the planet, and there are a lot of storms,” said Juno principal investigator Dr. Scott Bolton, from Southwest Research Institute.

“There is no sign of the latitudinal bands or zone and belts that we are used to – this image is hardly recognizable as Jupiter. We’re seeing signs that the clouds have shadows, possibly indicating that the clouds are at a higher altitude than other features.”

He added: “Saturn has a hexagon at the north pole. There is nothing on Jupiter that anywhere near resembles that. The largest planet in our Solar System is truly unique.”

Along with JunoCam snapping pictures during the flyby, all eight of Juno’s instruments were energized and collecting data.

This infrared image gives an unprecedented view of the southern aurora of Jupiter. The gas giant’s southern aurora can hardly be seen from Earth due to our home planet’s position in respect to Jupiter’s south pole. Juno’s unique polar orbit provides the first opportunity to observe this region of the planet in detail. The JIRAM camera acquired the view at wavelengths ranging from 3.3 to 3.6 microns – the wavelengths of light emitted by excited hydrogen ions in the polar regions. The view is a mosaic of three images taken just minutes apart from each other, about four hours after the perijove pass while the spacecraft was moving away from Jupiter. Image credit: NASA / JPL-Caltech / SwRI / MSSS.

The Jovian Infrared Auroral Mapper (JIRAM) acquired some remarkable images of Jupiter at its north and south polar regions in infrared wavelengths.

“JIRAM is getting under Jupiter’s skin, giving us our first infrared close-ups of the planet,” said JIRAM co-investigator Dr. Alberto Adriani, of the Istituto di Astrofisica e Planetologia Spaziali in Rome, Italy.

“These first infrared views of Jupiter’s north and south poles are revealing warm and hot spots that have never been seen before. And while we knew that the first-ever infrared views of Jupiter’s south pole could reveal the planet’s southern aurora, we were amazed to see it for the first time. No other instruments, both from Earth or space, have been able to see the southern aurora.”

“Now, with JIRAM, we see that it appears to be very bright and well-structured. The high level of detail in the images will tell us more about the aurora’s morphology and dynamics.”

Among the more unique data sets collected by the spacecraft was that acquired by Juno’s Radio/Plasma Wave Experiment (Waves), which recorded ghostly-sounding transmissions emanating from above the planet.

These radio emissions from Jupiter have been known about since the 1950s but had never been analyzed from such a close vantage point.

“Jupiter is talking to us in a way only gas-giant worlds can,” said Waves instrument co-investigator Dr. Bill Kurth, from the University of Iowa.

“Waves detected the signature emissions of the energetic particles that generate the massive auroras which encircle Jupiter’s north pole.”

“These emissions are the strongest in the Solar System. Now we are going to try to figure out where the electrons come from that are generating them.”

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Juno Sends Back Incredible New Images of Jupiter