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Jupiter’s chaotic storms have roots deep beneath its surface

The gaseous veil of Jupiter’s surface has long cast a pall over scientists’ quest to understand the giant planet’s depths. In particular, researchers have debated whether the bands of east-west winds that sculpt Jupiter’s distinctive surface, complete with the curlicues of stormy cyclones, extend deeper into the planet, or are merely superficial. Now, a series of papers from NASA’s Juno spacecraft, published today in Nature, has revealed that the roots of Jupiter’s winds indeed run deep. Since arriving at the gas giant in 2016, Juno has swung around the planet in an elliptical 53-day orbit; with each pass, Jupiter’s gravity has tugged the spacecraft back and forth, revealing glimpses of its interior through Doppler shifts in Juno’s radio signal collected on Earth. In these data, Juno’s scientists discovered an asymmetry in Jupiter’s north-south gravitational field that reflected shifting masses driven by rising winds from 3000 kilometers deep within the planet. These flows of hydrogen and helium, the team shows, are driven up by energy lost from the planet’s deeper interior, which rotates like a solid because of crushing high pressures. When compared with similar observations taken by Cassini before its dive into Saturn last year, the NASA missions could soon clarify the internal dynamics of gas giants, helping understand their origins—and the composition of worlds beyond our solar system.