36 POPULAR SCIENCEBy KELSEY D. ATHERTON + SOPHIE BUSHWICK
On July 4—870 million km from
the nearest Independence Day
barbecue—the solar-powered
Juno orbiter began circling
Jupiter’s poles, passing 4,200 km
above the planet’s clouds. “Nospacecraft has ever orbited this
close to Jupiter, in the heart of
the radiation belts, where the
magnetic field is this strong,”
says project scientist Steve
Levin. Protected from thatNASA JUNOJourney to the
Center of a Gas Giant