{"id":320752,"date":"2026-02-05T00:53:08","date_gmt":"2026-02-05T00:53:08","guid":{"rendered":"https:\/\/www.europesays.com\/ie\/320752\/"},"modified":"2026-02-05T00:53:08","modified_gmt":"2026-02-05T00:53:08","slug":"jupiter-is-smaller-and-more-squashed-than-previously-believed-new-juno-data-reveal","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/ie\/320752\/","title":{"rendered":"Jupiter is Smaller and More \u2018Squashed\u2019 than Previously Believed, New Juno Data Reveal"},"content":{"rendered":"

Using high-precision radio-occultation measurements from NASA\u2019s Juno mission and incorporating the effects of zonal winds, planetary scientists derived Jupiter\u2019s shape with an order-of-magnitude reduction in uncertainty, finding polar, equatorial and mean radii smaller than previous estimates made with NASA\u2019s Pioneer and Voyager missions.<\/strong><\/p>\n

\"This<\/p>\n

This visible-light image of Jupiter was created from data captured on January 11, 2017 using Hubble\u2019s Wide Field Camera 3. Near the top, a long brown feature called a \u2018brown barge\u2019 extends 72,000 km (nearly 45,000 miles) in the east-west direction. The Great Red Spot stands out prominently in the lower left, while the smaller feature nicknamed Red Spot Jr. (known to Jovian scientists as Oval BA) appears to its lower right. Image credit: NASA \/ ESA \/ NOIRLab \/ NSF \/ AURA \/ Wong et al. \/ de Pater et al. \/ M. Zamani.<\/p>\n

\u201cJupiter, the largest planet in the Solar System, is approximately an oblate spheroid (ellipsoid of revolution), meaning it is slightly flattened at the poles and bulging at the equator owing to its rapid 9\u2009h 55\u2009min 29\u2009s rotation period,\u201d said Dr. Eli Galanti from the Weizmann Institute of Science and colleagues.<\/p>\n

\u201cThis shape results from the balance between gravitational forces pulling inwards in the radial direction and centrifugal forces pushing outwards from the rotation axis, resulting, in the case of Jupiter, in the equatorial radius being about 7% larger than its polar radius.\u201d<\/p>\n

\u201cFor a body with constant density, the shape is an exact ellipsoid. However, Jupiter\u2019s interior density profile varies dramatically from the cloud level at around 1\u2009bar, where the density is less than 1\u2009kg\/m3, to the deep levels, where density reaches thousands of kg\/m3. \u201c<\/p>\n

\u201cThis leads to variations in the shape of the planet from an ellipsoid on the order of tens of kilometers, which are expressed as latitudinal variations in the gravity field.\u201d<\/p>\n

\u201cAdditional variations in Jupiter\u2019s shape come from the strong zonal winds observed at the cloud level.\u201d<\/p>\n

\u201cThese modify the centrifugal forces to create variations on the order of 10\u2009km, mostly at low latitudes.\u201d<\/p>\n

Previously, Jupiter\u2019s physical dimensions were based on data from six radio occultation experiments performed by NASA\u2019s Pioneer and Voyager missions in the 1970s.<\/p>\n

In a new study, the authors analyzed the radio occultation data obtained by Juno during 13 flybys of Jupiter, and incorporated the effects of zonal winds.<\/p>\n

\u201cRadio occultation is used to \u2018see\u2019 through the dense, opaque clouds of Jupiter\u2019s atmosphere to understand its internal structure,\u201d they explained.<\/p>\n

\u201cDuring an occultation experiment, Juno beams radio signals back to NASA\u2019s Deep Space Network on Earth.\u201d<\/p>\n

\u201cAs these signals pass through the charged upper layer of Jupiter\u2019s atmosphere, called the ionosphere, gases bend and delay the signals.\u201d<\/p>\n

\u201cBy measuring the change in frequency caused by this bending, we can calculate the temperature, pressure, and electron density of Jupiter\u2019s atmosphere at different depths. \u201c<\/p>\n

The team\u2019s results show that Jupiter is about 8 km narrower at the equator and 24 km flatter at the poles.<\/p>\n

\u201cIncorporating the effects of zonal winds, we derive Jupiter\u2019s shape with an order-of-magnitude reduction in uncertainty,\u201d the researchers said.<\/p>\n

\u201cAt the 1-bar pressure level, we find a polar radius of 66,842 km, an equatorial radius of 71,488 km and a mean radius of 69,886 km, which are 12\u2009km, 4\u2009km and 8\u2009km smaller than previous estimates, respectively.\u201d<\/p>\n

The findings<\/a> were published this week in the journal Nature Astronomy.<\/p>\n

_____<\/p>\n

E. Galanti et al. The size and shape of Jupiter. Nat Astron, published online February 2, 2026; doi: 10.1038\/s41550-026-02777-x<\/p>\n","protected":false},"excerpt":{"rendered":"Using high-precision radio-occultation measurements from NASA\u2019s Juno mission and incorporating the effects of zonal winds, planetary scientists derived…\n","protected":false},"author":2,"featured_media":320753,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[77],"tags":[1204,10210,18,10211,19,17,10212,2663,1024,29167,133,12809,10214,13911],"class_list":{"0":"post-320752","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-planet","9":"tag-atmosphere","10":"tag-eire","11":"tag-gas-giant","12":"tag-ie","13":"tag-ireland","14":"tag-juno","15":"tag-jupiter","16":"tag-nasa","17":"tag-radio-signal","18":"tag-science","19":"tag-size","20":"tag-solar-system","21":"tag-wind"},"share_on_mastodon":{"url":"","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/320752","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=320752"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/320752\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/320753"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=320752"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=320752"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=320752"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}