Jupiter is complicated

(written by lawrence krubner, however indented passages are often quotes). You can contact lawrence at: lawrence@krubner.com, or follow me on Twitter.


While Jupiter’s iconic red storm, stripes and girth may loom large in the skies and in our minds, surprisingly little is known about it. Among the many questions Juno set out to answer: Does the gas giant have a solid metal core? Does it have any structure beneath its banded atmosphere, or are its depths well-mixed? How much water lies within its body? And what powers its auroras and its magnetic field?

Now, data from just the first two passes are already offering up surprising answers to some of those longstanding questions.

Researchers have largely fallen into two camps as to what lies at Jupiter’s heart: a solid, metal-rich core, or mostly hydrogen. But the truth may lie somewhere in the middle.

“It does look like Jupiter has a core, but it’s very large,” said Scott Bolton, Juno’s principal investigator based at the Southwest Research Institute. “It’s diffuse; it’s not as concentrated as we thought. We don’t know exactly how it gets that way.”

…Even the auroras seemed to function differently than expected; the magnetic field, meanwhile showed an unprecedented level of structure when viewed up close.

Earth’s magnetic field is powered by a dynamo created by the flow of liquid metal in its core. Jupiter’s dynamo, scientists say, is produced by metallic hydrogen — hydrogen that’s so deep in Jupiter that the pressure has squeezed its electrons off, allowing the compressed gas to behave like a metal.

But the results show that Jupiter’s magnetic field might actually be generated higher up, in the shallower layer of molecular hydrogen (which is strange, since molecular hydrogen is a neutral compound).

“That’s very significant,” John Connerney, the mission’s deputy principal investigator at NASA’s Goddard Space Flight Center, and lead for Juno’s magnetometer, said at a press briefing Thursday.

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