New Juno Data Reveals Jupiter Is Much More Complicated Than Expected

The Juno spacecraft has spent time at Jupiter's south pole, sending images back from "beneath" the planet. NASA/JPL-Caltech/SwRI/MSSS/Betsy Asher Hall/Gervasio Robles
NASA's Juno spacecraft, which reached the planet Jupiter in July 2016 after a five-year, 1.7-billion-mile (2.7-billion-kilometer) journey, is exploring our solar system's biggest planet. It's taking advantage of a polar orbit that allows it to swoop down within 3,100 miles (4,990 kilometers) of the immense world's cloud tops. Imagine it this way: If Jupiter were the size of a basketball, Juno would be only about a third of an inch away.

That's the closest that any spacecraft has gotten to the immense planet without smashing into it, and it's a chance to take a more detailed look than ever before possible at an immense, faraway object. And as scientists analyze the initial data from the $1.13 billion mission, they're discovering that the gas giant appears to be significantly different than anyone would have imagined.
"Jupiter is not as simple as we thought it was," says Scott Bolton, a scientist at the Southwest Research Institute (SWRI) who is Juno's principal investigator. He describes the planet as having much more structure, variability and motion than scientists had envisioned. "Nobody expected Jupiter to have so much complexity, so deep."

As this SWRI press release details, Juno has eight scientific instruments designed to study the planet's magnetic field, atmosphere and interior structure, and they show that Jupiter is far more than just a giant ball of gases.

"Until Juno's arrival, our understanding of Jupiter's atmosphere was based on what we can see from the side, near the equator," says Steven M. Levin, a Juno project scientist at NASA's Jet Propulsion Laboratory, in an email. "From that angle, Jupiter appears dynamic, but organized. Large belts and zones form a consistent pattern of jet streams which give the planet its familiar striped appearance. The new polar images from Juno look nothing like that. Around the poles, Jupiter looks chaotic, without an obvious, stable structure, and certainly without the regular stripes we see near the equator."

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