Juno Mission Uncovers Jupiter’s Winds Penetrating Cylindrically, Resolving Decades-Long Debate
In a groundbreaking discovery, NASA’s Juno mission has revealed that Jupiter’s atmospheric winds extend cylindrically, parallel to its rotation axis. This finding provides valuable insights into the long-debated internal structure of the gas giant. Recently published in the journal Nature Astronomy, a study detailing the research sheds light on the violent nature of Jupiter’s turbulent atmosphere, captivating astronomers and planetary scientists for decades.
Since entering Jupiter’s orbit in 2016, the Juno spacecraft has been closely observing the planet’s atmospheric activities. During its 55 close flybys, Juno’s suite of science instruments has delved beneath the planet’s turbulent cloud deck to unravel the mysteries of its internal workings. To study the planet’s interior, Juno employs radio science, tracking the spacecraft’s radio signal as it speeds past Jupiter at nearly 130,000 mph (209,000 kph). By measuring small changes in velocity—as slight as 0.01 millimeter per second—caused by variations in Jupiter’s gravity field, the mission gains crucial insights into the planet’s atmospheric dynamics.
These measurements have led to a range of significant discoveries, including the identification of a dilute core deep within Jupiter and determining the extent of its zones and belts, which reach approximately 1,860 miles (3,000 kilometers) below the cloud tops. To determine the location and nature of Jupiter’s winds, the researchers utilized a mathematical technique commonly used to model gravitational variations and surface elevations of rocky planets like Earth. By applying this technique to Jupiter, the study’s authors accurately mapped the winds at depth. Using high-precision data from Juno, they achieved a four-fold increase in resolution compared to previous models based on data from NASA’s Voyager and Galileo missions.
Ryan Park, a Juno scientist and the lead of the mission’s gravity science investigation from NASA’s Jet Propulsion Laboratory, noted, We applied a constraining technique developed for sparse data sets on terrestrial planets to process the Juno data. This is the first time such a technique has been applied to an outer planet.
The measurements of Jupiter’s gravity field matched a two-decade-old model that proposed Jupiter’s east-west zonal flows—powerful atmospheric currents—extend inward from the planet’s cloud-level zones and belts. However, the measurements also revealed a distinct pattern: rather than radiating out in all directions, the zonal flows extend inward cylindrically, aligned with Jupiter’s rotation axis. This finding resolves a debate that has persisted since the 1970s about the structure of Jupiter’s deep atmospheric winds.
Yohai Kaspi, the lead author of the study and a Juno co-investigator at the Weizmann Institute of Science in Israel, expressed excitement over the results, saying, All 40 gravity coefficients measured by Juno matched our previous calculations of what we expect the gravity field to be if the winds penetrate inward on cylinders. When we realized all 40 numbers exactly match our calculations, it felt like winning the lottery.
Apart from enhancing our understanding of Jupiter’s internal composition and origins, this new gravity model has wider implications for studying other planetary atmospheres. Juno, currently in an extended mission, continues to conduct flybys of Jupiter, its icy moons Ganymede and Europa, as well as close flybys of Io. With each milestone achieved, the mission cements its position as a significant contributor to our understanding of giant planets within our solar system and beyond.
Scott Bolton, the principal investigator of the Juno mission at the Southwest Research Institute, remarked, As Juno’s journey progresses, we’re achieving scientific outcomes that truly define a new Jupiter and that likely are relevant for all giant planets, both within our solar system and beyond. The resolution of the newly determined gravity field is remarkably similar to the accuracy we estimated 20 years ago. It is great to see such agreement between our prediction and our results.
The recent study on Jupiter’s atmospheric winds deepens our knowledge of this awe-inspiring gas giant and highlights the invaluable contributions made by the Juno mission. With its cutting-edge technology and unwavering dedication, Juno provides scientists with an unprecedented window into the intricate workings of Jupiter’s innermost secrets.
