8 mar 2018

NASA mission discovers Jupiter's inner secrets


NASA spacecraft Juno has collected new data on its mission to Jupiter revealing some of the swirling inner mysteries of the giant gas-planet.
The surface of Jupiter, the fifth planet from the sun and the largest in the solar system, consists of alternating bright and dark bands of gas and winds flowing in opposite directions at massive speed.
Previously there have been extensive studies of the helium-and-hydrogen planet's surface, but now gravity measurements collected by Juno indicate that this turbulent outer layer extends to a depth of 1,900 miles (3,000 kilometers).
    "Galileo viewed the stripes on Jupiter more than 400 years ago," Yohai Kaspi, Juno co-investigator from the Weizmann Institute of Science, Rehovot, Israel, and lead author of a Nature paper on Jupiter's deep weather layer, was quoted as saying on NASA's website.
    "Until now, we only had a superficial understanding of them and have been able to relate these stripes to cloud features along Jupiter's jets. Now, following the Juno gravity measurements, we know how deep the jets extend and what their structure is beneath the visible clouds," said Kaspi, who likened the advancement to going from a "2-D picture to a 3-D version in high definition."
    "On a gas planet, such an asymmetry can only come from flows deep within the planet; and on Jupiter, the visible eastward and westward jet streams are likewise asymmetric north and south.
    "The deeper the jets, the more mass they contain, leading to a stronger signal expressed in the gravity field. Thus, the magnitude of the asymmetry in gravity determines how deep the jet streams extend."
    The mission also found that the planet's interior rotates as a solid body, despite its fluid nature.
    "This is really an amazing result, and future measurements by Juno will help us understand how the transition works between the weather layer and the rigid body below," said Tristan Guillot, a Juno co-investigator from the Université Côte d'Azur, Nice, France, and lead author of the paper on Jupiter's deep interior.
    "Juno's discovery has implications for other worlds in our solar system and beyond."