Nasa releases first close-up images of Jupiter taken by Juno spacecraft Guardian

New images of Jupiter offer glimpse into what lies under planet's skin

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Juno spacecraft reached Jupiter after a nearly five-year journey to the planet that ended with a delicate maneuver into orbit past intense bands of radiation

Nasa scientists have received their first glimpse of Jupiter’s north pole and the auroras rippling across its southern pole, with new images sent from the agency’s Juno spacecraft.

“It looks like nothing we have seen or imagined before,” said Scott Bolton, Juno’s principal investigator. “It’s bluer in color up there than other parts of the planet, and there are a lot of storms.”

Juno reached Jupiter in early July, after a nearly five-year journey to the gas giant that ended with a delicate maneuver into orbit past the planet’s intense bands of radiation. The spacecraft, named after the goddess married to the chief Roman god Jupiter, then executed the first of three dozen flybys around the planet on 27 August, dipping to only 2,500 miles above its buffeting clouds – the closest ever by a spacecraft.

An infrared image of the southern aurora of Jupiter. Photograph: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM

But the images sent from the poles, Bolton said in a statement, are “hardly recognizable as Jupiter”. They show “signs that the clouds have shadows”, he added, meaning they might be above other features, like weather and storms unlike those on the system’s other gas giants – Saturn, Uranus and Neptune.

“Saturn has a hexagon at the north pole,” Bolton said. “There is nothing on Jupiter that anywhere near resembles that. The largest planet in our solar system is truly unique. We have 36 more flybys to study just how unique it really is.”

Jupiter’s equator is banded by belts and zones of clouds that have been visible for decades, but Juno has revealed a vastly different system at its farthest reaches to the north and south. Gigantic, rotating storms akin to Earth’s hurricanes move clockwise and counterclockwise around the poles, dappling them with powerful weather.

Ecstasy as Juno reaches Jupiter, but now the hard work starts

While Juno’s camera took photos of the planet’s clouds, the spacecraft’s other instruments collected six megabytes of data that took a day and a half to transmit back to Earth. With an instrument called Waves, for instance, researchers were able to record radio signals coming off the planet’s auroras: emissions of the high-energy particles that create the lights. They then shifted them down into a range audible to humans.

The result are eerie wails, dotted by static, that shift in pitch with the intensity of the auroral waves and sound as if they were made by some ghostly undersea creature. The gigantic wavelengths, about a kilometer long, have been called “kilometric emissions” since the 1950s but have never been analyzed from so close to the planet.

“Jupiter is talking to us in a way only gas-giant worlds can,” said Bill Kurth, a team researcher based at the University of Iowa, Iowa City. “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.”

Juno’s infrared mapper, meanwhile, briefly revealed what lies “under Jupiter’s skin”, said Alberto Adriani, a researcher from Rome’s Institute for Space Astrophysics and Planetology. The infrared images revealed previously unknown warm and hot spots, Ariani said, and a surprisingly clear first image of Jupiter’s southern aurora.

A video released by the space agency showed how the infrared mapper, scanned across the planet, reveals Jupiter’s bands of clouds moving in a fiery glow. Jupiter’s southern aurora is only barely visible from Earth because of the planets’ respective positions in the solar system.

Jupiter’s south polar region became increasingly visible. — Jupiter’s south polar region as captured by Juno. Photograph: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM

“No other instruments, both from Earth or space, have been able to see the southern aurora,” he said. “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.”

Juno will make 36 more passes around the planet, each lasting 14 days, before it descends to its doom within the veil of clouds. Nasa has guarded the spacecraft’s most sensitive sensors with titanium shields against the planet’s extraordinarily harsh radiation around the equator, and researchers hope that the instruments will last long enough on its next 36 orbits to reveal more about what lies under the clouds, whether Jupiter has a solid core, why the auroras are so bright and whether the gas giant hides significant water.

This year, Nasa researchers used the Hubble space telescope to capture images of Jupiter’s swirling auroras, powered by high-energy particles colliding with gas atoms at the planet’s intensely magnetic pole.

Only one other spacecraft has visited Jupiter: the vessel named Galileo, which orbited from 1995 to 2003 and was also deliberately crashed at the end of its mission. Galileo could not send as detailed or close data from the planet as Juno can, and the past record for a close approach was held by Nasa’s Pioneer 11 spacecraft, came 27,000 miles from Jupiter in 1974.