Seen from a different angle, Jupiter looks like a whole new world.
After flying within about 2,500 miles of the planet's cloud tops on Aug. 27, NASA's Juno spacecraft has sent home unprecedented images of Jupiter's north pole, revealing a stormy fluid-scape that looks as if it could be on a totally different gas giant.
"The north pole of Jupiter really doesn't look a whole lot like the rest of the planet," Steve Levin, Juno's project scientist at Jet Propulsion Laboratory, said in an interview.
Last week's flyby was the spacecraft's first such pass with all its science instruments turned on, as well as the closest of the 36 orbital flybys that the spacecraft is set to make during its mission. While Jupiter is the largest planet in the solar system by far, there's surprisingly little known about its polar regions — and so Juno's close-up camera work was bound to deliver a few surprises.
As the JunoCam imager revealed, Jupiter's north pole is bluer than better-known areas of the planet, which are often dominated by red, orange and brown hues. Gone are those iconic bands of light and dark; in their place are a whole lot of storms.
Even the storms appear different at the poles, Levin added: they look smaller and more clustered, unlike the squalls in other parts of Jupiter that swirl at the boundaries between the planet's stripes of moving fluid. (Jupiter's Great Red Spot is a prime example.)
"It looks like nothing we have seen or imagined before," Scott Bolton, Juno's principal investigator at the Southwest Research Institute, said in a statement.
There even appear to be shadows visible beneath the clouds, Bolton added. That's a sign that those clouds might hover well above the planet's other visible features.
Storms on Jupiter are very tall, unlike those on Earth, which are shallow compared to the size of the area they cover, Levin said. The shadows at the pole could mean that scientists will get a better look at their three-dimensional structure and the dynamics that shape them.
In infrared light, Jupiter's poles still put on a show. The Jovian Infrared Auroral Mapper revealed hot spots at both poles, and captured the south pole's bright aurora in high detail.
Juno didn't just watch Jupiter's auroras — it listened to them, using its Radio/Plasma Wave Experiment to record transmissions that have never been analyzed using such up-close-and-personal data.
Scientists are already analyzing the data generated during the six-hour loop from the north pole to the south pole. And they have yet to release data from several other sensors, including their microwave radiometer (which senses water content) and their gravity science instrument (which will map the planet's internal structure).
Both these measurements could profoundly affect our view of the planet's evolution, and have implications for our understanding of the development of the solar system.
In the meantime, Juno is hurtling back into space for another 53.5-day orbit. After that, it will settle into shorter two-week orbits, providing scientists on the ground with a wealth of new information.
"It's going to be a flood," Levin said, "like drinking from a fire hose."
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8 p.m.: This story was updated with additional details and comment from Steve Levin.