Scientists are finding that the inside of Jupiter is just as interesting as the part of the planet's atmosphere that we can see.

At the center of the planet is a liquid mixture of the elements hydrogen and helium. Scientists say large atmospheric jet streams and unusual gravitational qualities also exist.

Scientists have been closely studying information sent back to Earth from NASA's Juno spacecraft. It has been orbiting the solar system's largest planet since 2016.

Juno is providing researchers with what they called a new understanding of Jupiter's structure.

Until now, scientists have had little information about what is below Jupiter's thick red, brown, yellow and white clouds.

"Juno is designed to look beneath these clouds," said Yohai Kaspi. He is a planetary science professor with the Weizmann Institute of Science in Israel. Kaspi led part of the research using Juno's new measurements of Jupiter's gravity.

Luciano Iess is an aerospace engineering professor at Sapienza University of Rome. He also led part of the research.

"On Jupiter, a gaseous planet without a solid surface, we can only gather information from orbit," he said.

Jupiter is called a gas giant planet. Unlike Earth and Mars which are rocky planets, Jupiter is about 99 percent hydrogen and helium. Information sent by Juno showed that deeper under the surface, Jupiter's gas turns into a hot, dense metallic liquid.

The scientists said Jupiter's jet streams form stripes around the planet moving about 3,000 km below the cloud tops. Deep inside, the planet is made of a liquid hydrogen and helium mixture that turns as if it were a solid body.

Planetary scientist Tristan Guillot of the Université Côte d'Azur in Nice said the very center may be made of high-pressure and high-temperature rocks and perhaps water. He added, "but it is believed to be fluid as well, not solid,"

Juno showed a small but important asymmetry between the gravitational field of Jupiter's northern and southern halves. Kaspi said this difference is driven by the large jet streams.

The deeper the jet streams go, the more mass they contain, causing a strong effect on Jupiter's gravitational field, he said.

The research was published in the journal Nature.

Jupiter, the fifth planet from the sun, is much larger than the solar system's other planets, measuring about 143,000 kilometers around at its equator.

The planet is big enough for 1,300 Earths to fit inside.

I'm Susan Shand.

Reuters reported this story. Susan Shand adapted it for Learning English. Mario Ritter was the editor.