NASA's Juno spacecraft has revealed that Jupiter's iconic striped bands, caused by immensely powerful winds, extend to a depth of about 3,000km below the surface. The findings also provide a partial answer to the question of whether the planet has a core, "showing that the inner 96% of the planet rotates 'as a solid body,' even though technically it is composed of an extraordinarily dense mixture of hydrogen and helium gas," reports The Guardian. From the report: The findings are published in four separate papers in the journal Nature, describing the planet's gravitational field (surprisingly asymmetrical), atmospheric flows, interior composition and polar cyclones. A crucial question was whether the bands on Jupiter, caused by air currents that are five times as strong as the most powerful hurricanes on Earth, were a "weather" phenomenon comparable to the Earth's jet streams or part of a deep-seated convection system. Juno's latest observations point to the latter, showing the jets continued to around 3,000km beneath the surface -- deep enough to cause ripples and asymmetries in the planet's gravitational field that were perceptible to detectors on the spacecraft. On Earth, the atmosphere represents about a millionth of the mass of the whole planet. The latest work suggests that on Jupiter the figure is closer to 1%. The new findings, based on extremely sensitive gravitational measurements, also begin to paint a picture of the internal structure of the planet.