Jupiter is mostly hydrogen and helium. The amounts match those in the primordial solar nebula. It also contains heavy metals. Despite being a small part of Jupiter, metals tell astronomers a much.

Jupiter's metal concentration and distribution suggest it ate rocky planetesimals in its childhood, says a new research.

Since Juno's arrival at Jupiter in July 2016 and data collection began, our knowledge of Jupiter's formation and evolution has changed. Gravity Science is a mission feature. It communicates with Juno and Earth's Deep Space Network. It measures Jupiter's gravitational field and reveals its composition.

Jupiter developed by accumulating rock. After millions of years of rapid gas accretion from the solar nebula, Jupiter became massive. But there's a big question about rocky accretion's beginning. Did it accrete planetesimal-sized rocks? Did it accumulate pebbles? Jupiter formed differently depending on the response.

New research answers this question. Astronomy & Astrophysics published 'Jupiter's inhomogeneous envelope' Yamila Miguel is a Leiden Observatory & Netherlands Institute for Space Research assistant professor of astrophysics.

JunoCam's photographs of Jupiter are stunning. But appearances deceive. Clouds and storms are merely the thin outermost 50 km (31 miles) of the planet's atmosphere. Jupiter's deep atmosphere holds the secret to its genesis and development.

Jupiter is the Solar System's oldest planet. How long did it take to form? Juno's Gravity Science experiment was used to study the planet's elements. Gravity Science measured pebble dispersion throughout Jupiter's atmosphere to better understand its creation. Before Juno's Gravity Science experiment, Jupiter's gravity harmonics were unknown.

Jupiter's atmosphere isn't as homogeneous as imagined. Near the planet's core, more metals exist. Metals total 11 to 30 Earth masses.

Data-driven, the team modelled Jupiter's interior dynamics. In this work, they 'build the most extensive and diverse collection of Jupiter interior models to date' Two models were developed. First are 3-layer models, then dilute core.

Jupiter can acquire metals through the accretion of small pebbles or larger planetesimals, said main author Miguel. Once a planet is big enough, it pushes forth stones. Before that, Jupiter's metal wealth seemed unattainable. So we can rule out Jupiter's origin from stones. Planetesimals are too huge to block, therefore they must have helped.

Jupiter's metal abundance falls away from the core. Scientists suspected the planet's deep atmosphere had convection. Miguel: 'We imagined Jupiter had convection, like boiling water, to mix it.' Our findings disagree.

The authors show that Jupiter's heavy element abundance is not uniform. 'Our results show that Jupiter continued to accrete heavy elements while its hydrogen-helium envelope grew, counter to predictions based on the pebble-isolation mass in its simplest incarnation, favouring planetesimal-based or more sophisticated hybrid models.'

Jupiter didn't mix through convection after it formed, even when it was young and heated. The team also studied gaseous exoplanets and determined their metallicity. 'Our result... provides a base example for exoplanets: a non-homogeneous envelope suggests that the observed metallicity is a lower limit to the planet bulk metallicity.'

Jupiter's metallicity couldn't be determined remotely. Juno allowed scientists to indirectly detect metallicity. Remote atmosphere observations of exoplanets may not reflect the planet's bulk metallicity.

James Webb Space Telescope will measure exoplanet atmospheres and establish their composition. This study suggests Webb's data may not capture what's happening in big gas planets' lower layers.