The top and bottom of Jupiter are pockmarked with a chaotic mélange of swirls that are actually immense storms hundreds of miles across. The planet’s interior core appears bigger than expected, generating surprisingly strong magnetic fields. Auroral lights shining in Jupiter’s polar regions seem to operate in a reverse way to those on Earth. And plumes of ammonia may be rising out of the planet.
Those are some of the early findings of scientists working on NASA’s Juno mission, an orbiter that arrived at Jupiter on July 4 last year. With a looping elliptical orbit, Juno is making repeated dives to within about 2,600 miles of the cloud tops. The spacecraft’s instruments peer far beneath, giving scientists glimpses of the inside of Jupiter, the solar system’s largest planet.
Two papers, one describing the polar storms, the other examining the magnetic fields and auroras, appear in this week’s issue of the journal Science. A cornucopia of 44 additional papers are being published in the journal Geophysical Research Letters.
NASA’s earlier missions — the flybys of Voyager 1 and 2 in 1979 and an extended orbital visit by Galileo from 1995 to 2003 — looked at Jupiter from the side. What the spacecraft could see of the polar regions was from a sharp angle, with details hard to make out.
“You never really see the whole thing in all its glory at the same time,” said John E.P. Connerney, a scientist at NASA’s Goddard Space Flight Center in Greenbelt, Md., and deputy principal investigator on the mission.
