Jupiter continues to amaze and it is partly because of the Juno mission that is providing astronomers and scientists with ample amounts of data to unravel secrets about the gaseous giant.
Recently three papers have been published in journal Nature that provide answer to a question that scientists have been asking ever since Galileo first observed the famous stripes of Jupiter: Are the colorful bands just a pretty surface phenomenon, or are they a significant stratum of the planet?
Analyzing the data collected by NASA’s Juno spacecraft, scientists were able to reveal that the stripes – belts of strong winds circling the planet – extend to a depth of about 3,000 km. That is quite a bit more than previous estimates, and it is revising scientists’ picture of Jupiter’s atmosphere as well as its inner layers.
Juno is providing amazing quality and quantity of data about Jupiter and what lies behind the planet’s surface. Among the measurements Juno beams back to Earth are those of the planet’s gravity field. This is done via radio waves: As the planet’s gravity pulls on the spacecraft in its flyby, the radio signal is also shifted a bit; this shift in the wavelengths, though tiny, is measurable. And since the flybys are in different orbits each time, they can sample the gravitational field of different parts of the planet.
Authors of the latest studies have built mathematical tools to analyze the gravitational field data that they were optimistic will enable them to get a grasp on Jupiter’s atmosphere.
The wind belts that encircle Jupiter are much stronger than the fiercest winds on Earth, and they have lasted for at least hundreds of years. As these jets flow in bands from east to west or west to east, they disrupt the even distribution of mass on the planet. Thus by measuring the imbalance – changes in the planet’s gravity field – their analytical tools would be able to calculate how deep the storms extend below the surface.
The scientists looked for anomalies – measurements that show the planet deviating from a perfect sphere. They expected a certain anomaly because the planet’s rotation squashes its shape slightly, but additional anomalies in the measurements would most likely be due to winds in the atmosphere.
Based on the asymmetry in the gravitational fields between north to south, the researchers determined that the wind belts – these stripes observed by Galileo – extend 3,000 km deep. Authors of the study also developed a method of determining not only the overall depth of the flow, but also precisely how those flows, hidden beneath Jupiter’s clouds, change with depth.
The calculations based on these findings show that Jupiter’s atmosphere is 1% of its total mass. That may not sound like a lot, but in comparison, Earth’s atmosphere is less than a millionth of its total mass.
The subject of Jupiter’s core is not yet closed, and the researchers aim analyze further measurements to see whether Jupiter has a solid core, and if so, to determine its mass.