Hyperion | Saturn’s Moon, Irregular Shape & Orbit

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overflow-hidden d-flex overflow-hidden text-nowrap ml-15"> <a href="https://cdn.britannica.com/12/92812-050-00CAE6FB/agglomeration-moon-Hyperion-Saturn-Cassini-spacecraft-photograph-September-26-2005.jpg" data-href="/media/1/279603/88426" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/12/92812-004-35F58424/agglomeration-moon-Hyperion-Saturn-Cassini-spacecraft-photograph-September-26-2005.jpg" alt="Hyperion" height="50" /> </a> <a href="https://cdn.britannica.com/21/3921-050-2DF6C399/moon-Hyperion-Saturn-photograph-violet-images-distance.jpg" data-href="/media/1/279603/14096" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/21/3921-004-BD180620/moon-Hyperion-Saturn-photograph-violet-images-distance.jpg" alt="Hyperion, moon of Saturn. This photograph was compiled from three images taken through violet, clear, and green filters by Voyager 2 from a distance of about 500,000 km (310,000 miles)." height="50" /> </a> <a href="https://cdn.britannica.com/16/96316-050-3CF12855/Hyperion-moon-Saturn-moons-solar-system-hamburger.jpg" data-href="/media/1/279603/90617" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/16/96316-004-4BE8BC0F/Hyperion-moon-Saturn-moons-solar-system-hamburger.jpg" alt="Hyperion is a moon of Saturn. Unlike most moons in the solar system, Hyperion is not spherical (ball-shaped). Instead it is shaped something like a thick hamburger patty. Hyperion may be made of ice." height="50" /> </a> </div> <button disabled class="prev-button js-prev-button position-absolute btn btn-circle shadow btn-blue " aria-label="Previous"> <span class="material-icons md-24" data-icon="keyboard_arrow_left"></span> </button> <button disabled class="next-button js-next-button position-absolute btn btn-circle shadow btn-blue " aria-label="Next"> <span class="material-icons md-24" data-icon="keyboard_arrow_right"></span> </button> </div> </div> <div class="mb-30 tlr-related-quizzes"> <div class="text-gray-900 p-5 font-serif font-14 font-weight-bold mx-10 mb-10"> Quizzes </div> <div class="imagelink-with-image-on-the-side card card-horizontal tlr-img-with-side-link ml-15 link-gray-900 mb-10" > <div class="position-relative card-media" style="flex: 0;"> <a class="ilf-image position-relative" href="/quiz/space-odyssey"> <img loading="lazy" src="https://cdn.britannica.com/92/95392-131-F6284677/orbits-planets-bodies-solar-system.jpg?w=200&h=200&c=crop" alt="The orbits of the planets and other elements of the solar system, including asteroids, Kuiper belt, Oort cloud, comet" width="200" height="200" /> </a> </div> <div class="card-body ilf-content"> <a class="font-weight-semi-bold d-block mb-5 font-16 ilf-title" href="/quiz/space-odyssey" >Space Odyssey</a> </div> </div> <div class="imagelink-with-image-on-the-side card card-horizontal tlr-img-with-side-link ml-15 link-gray-900 mb-10" > <div class="position-relative card-media" style="flex: 0;"> <a class="ilf-image position-relative" href="/quiz/planets-and-the-earths-moon"> <img loading="lazy" src="https://cdn.britannica.com/74/166074-131-677298A0/Saturn-rings-planet-solar-system-Space-Art.jpg?w=200&h=200&c=crop" alt="Saturn. 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Hyperion's interior may be a loose agglomeration of ice blocks interspersed with voids, which would account for its low mean density (half that of water ice) and would explain its unusual “spongy” appearance in Cassini images.</span></span> <button class="js-more-btn d-none btn btn-unstyled font-12 bg-white js-content" aria-label="Toggle more/less fact data"> <span class="link-blue">(more)</span> </button> </span> </div> </figcaption> </figure> </div><div class="topic-header"> <div class="d-flex align-items-top justify-content-between"> <div class="d-flex flex-column"> <div> <div> <h1>Hyperion</h1></div> </div> <div class="topic-identifier font-16 font-md-20">astronomy</div> </div> </div> <div class="d-none d-sm-flex flex-row"> <div class="mr-10 mb-15"> <button class="ai-ask-button btn border-2 btn-sm js-inline-ai-ask-button btn-outline-red-400 border-red-400"> Ask the Chatbot a Question </button> </div> <div class="d-none d-sm-block md-topic-tools qa-action-buttons mb-15" data-topic-id="279603"> <button class="js-tooltip btn btn-sm btn-outline-blue border pr-10 border-2" > <em class="material-icons md-icon ml-n10 my-n5 mr-5" data-icon="more_vert"></em> More Actions </button> <div class="md-more-popover popover popover-sm p-0 font-14 z-1"> <div> <a class="js-modal btn btn-sm btn-link gtm-topic-tool font-weight-bold btn-link" href="/print/article/279603" target="_blank" > <em class="material-icons mr-5 ml-n10 my-n5 md-icon" data-icon="print"></em> Print </a> </div> <div> <button class="js-modal qa-cite-modal-button btn btn-sm btn-link gtm-topic-tool font-weight-bold btn-link" data-modal="[data-topic-id=279603] .md-cite-modal"> <em class="material-icons mr-5 ml-n10 my-n5 md-icon" data-icon="verified"></em> Cite </button> <div class="md-cite-modal size-lg d-none"> <div class="md-modal-body"> <div class="h2 font-serif d-flex align-items-center pb-15 border-bottom mb-15"> <em class="material-icons text-blue mr-10">verified</em>Cite </div> <div class="font-serif"> While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. </div> <div class="label mt-20 mb-10">Select Citation Style</div> <select class="js-citation-format-select form-select"> <option selected value="mla">MLA</option> <option value="apa">APA</option> <option value="chicago">Chicago Manual of Style</option> </select> <div class="citation font-serif border rounded p-15 mt-20" data-authors="William B. Hubbard" data-title="Hyperion" data-published-date="6 Jun. 2023" data-url="https://www.britannica.com/topic/Hyperion-astronomy" > <div class="citation-text"></div> </div> <button class="js-copy-citation-button mt-20 btn btn-xs btn-outline-blue border shadow-sm pr-10" > <em class="material-icons md-icon ml-n10 my-n5 mr-5" data-icon="file_copy"></em> <span class="js-citation-status-text">Copy Citation</span> </button> </div> </div> </div> <div> <button class="js-share-modal-button js-modal btn btn-sm btn-link gtm-topic-tool font-weight-bold btn-link" data-modal="[data-topic-id=279603] .md-share-modal"> <em class="material-icons mr-5 ml-n10 my-n5 md-icon" data-icon="share"></em> Share </button> <div class="md-share-modal size-lg d-none qa-share-modal"> <div class="md-modal-body"> <div class="h2 font-serif d-flex align-items-center pb-15 border-bottom"> <em class="material-icons text-blue mr-10" data-icon="share"></em> Share </div> <div class="label my-20">Share to social media</div> <div class="md-social-toolbar-circle d-flex align-items-start inverted" data-value="share" title="Hyperion" data-url="https://www.britannica.com/topic/Hyperion-astronomy" > <a class="social-icon facebook justify-content-center d-flex align-items-center align-self-center" data-provider="facebook" href="https://www.facebook.com/BRITANNICA/" target="_blank" rel="noopener"><span>Facebook</span></a> <a class="social-icon x justify-content-center d-flex align-items-center align-self-center" data-provider="x" href="https://x.com/britannica" target="_blank" rel="noopener"><span>X</span></a> </div> <div class="label pt-20 mt-20 mb-5 border-top">URL</div> <a class="font-serif text-truncate d-inline-block" href="https://www.britannica.com/topic/Hyperion-astronomy">https://www.britannica.com/topic/Hyperion-astronomy</a> </div> </div> </div> <div> <button class="js-feedback-modal-button js-modal btn btn-sm btn-link gtm-topic-tool font-weight-bold btn-link" data-modal=".md-feedback-modal"> <em class="material-icons mr-5 ml-n10 my-n5 md-icon" data-icon="message"></em> Feedback </button> </div> <div> <button class="qa-external-website-modal-button js-modal btn btn-sm btn-link gtm-topic-tool font-weight-bold btn-link" data-modal="[data-topic-id=279603] .md-websites-modal"> <em class="material-icons md-icon ml-n10 mr-5" data-icon="link"></em> External Websites </button> </div> </div> <div class="md-feedback-modal size-lg d-none"> <div class="md-modal-body"> <div class="h2 font-serif pb-15 border-bottom"> Feedback </div> <form method="post" action="/submission/feedback/279603"> <div class="my-20"> Corrections? 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Let us know if you have suggestions to improve this article (requires login). </div> <div class="type-menu"> <label for="feedback-type" class="label mb-10">Feedback Type</label> <select id="feedback-type" class="form-select mb-30" name="feedbackTypeId" required> <option value="" selected="selected">Select a type (Required)</option> <option value="1">Factual Correction</option> <option value="2">Spelling/Grammar Correction</option> <option value="3">Link Correction</option> <option value="4">Additional Information</option> <option value="5">Other</option> </select> </div> <label for="feedback" class="label mb-10">Your Feedback</label> <textarea id="feedback" class="form-control mb-30" name="feedback" maxlength="3000" rows="7" required></textarea> <button class="btn btn-blue" type="submit">Submit Feedback</button> </form> <div class="success-messaging d-none mt-30"> <div class="title">Thank you for your feedback</div> <p>Our editors will review what you’ve submitted and determine whether to revise the article.</p> </div> </div> </div> <div class="md-websites-modal size-lg d-none"> <div class="md-modal-body"> <div class="h2 font-serif pb-15 border-bottom font-weight-bold"> External Websites </div> <div class="pb-20"> <ul class="list-unstyled mt-20 lh-lg"> <li><a class="external" href="https://solarsystem.nasa.gov/moons/saturn-moons/hyperion/in-depth/" target="_blank" rel="noopener ">NASA - Solar System Exploration - Hyperion</a></li> </ul> </div> </div> </div> </div> </div> <div class="toc-header-marker"></div> <button class="ai-ask-button btn border-2 js-header-ai-ask-button d-none btn-sm btn-outline-red-400 border-red-400 mr-0 mr-lg-10 ml-5 ml-sm-10 ml-lg-0 p-10"> Ask the Chatbot a Question </button> <div class="md-byline module-spacing "> <div class="font-serif font-12"> <span class="written-by text-gray-700"> Written by </span> <div class="editor-popover popover p-0"> <a class="d-block p-20 gtm-byline font-12 byline-contributor" href="/contributor/William-B-Hubbard/3949" > <div class="editor-title font-16 font-weight-bold">William B. Hubbard</div> <div class="editor-description font-12 font-serif mt-5 clamp-description text-black">Professor of Planetary Sciences, University of Arizona, Tucson. Author of <i>Planetary Interiors.</i></div> </a> <div data-popper-arrow></div> </div> <span class="btn btn-link editor-link p-0 qa-byline-link gtm-byline font-12 byline-contributor text-decoration-underline"> William B. Hubbard</span></div> <div class="font-serif font-12 text-gray-700"> <span class="qa-fact-checked-by">Fact-checked by</span> <div class="editor-popover popover p-0"> <a class="d-block p-20 font-12" href="/editor/The-Editors-of-Encyclopaedia-Britannica/4419" > <div class="editor-title font-16 font-weight-bold">The Editors of Encyclopaedia Britannica</div> <div class="editor-description font-12 font-serif mt-5 text-black">Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors.</div> </a> <div data-popper-arrow></div> </div> <span class="btn btn-link editor-link p-0 qa-byline-link font-12 "> The Editors of Encyclopaedia Britannica</span></div> <div class="last-updated font-12 font-serif"> <a class="byline-edit-history" href="https://www.britannica.com/topic/Hyperion-astronomy/additional-info#history" rel="nofollow">Article History</a> </div></div> </div> <button class="d-flex d-lg-none btn btn-outline-blue border rounded-sm shadow-sm mobile-toc-button gtm-mobile-toc-inline-button d-none d-sm-block js-sections-inline-button module-spacing btn d-lg-none"> <em class="material-icons mr-5 ml-n10 my-n5 md-icon" data-icon="toc"></em> Table of Contents </button> <div class="d-flex d-sm-none flex-row"> <button class="d-flex d-lg-none btn btn-outline-blue border rounded-sm shadow-sm mobile-toc-button gtm-mobile-toc-inline-button js-sections-inline-button module-spacing"> <em class="material-icons mr-5 ml-n10 my-n5 md-icon" data-icon="toc"></em> Table of Contents </button> <button class="ai-ask-button btn border-2 ai-ask-button btn border-2 module-spacing btn-sm js-inline-ai-ask-button btn-outline-red-400 border-red-400 p-10 ml-5"> Ask the Chatbot a Question </button> </div> <span class="marker before-article"></span><section data-level="1" id="ref1"><span class="marker PREMOD1 mod-inline"></span><p class="topic-paragraph"><strong><span id="ref24233"></span>Hyperion</strong>, major <a href="https://www.britannica.com/science/moon-natural-satellite" class="md-crosslink autoxref " data-show-preview="true">moon</a> of <a href="https://www.britannica.com/place/Saturn-planet" class="md-crosslink " data-show-preview="true">Saturn</a>, notable in that it has no regular rotation period but tumbles in an apparently random fashion in its <a href="https://www.britannica.com/science/orbit-astronomy" class="md-crosslink " data-show-preview="true">orbit</a>. Hyperion was discovered in 1848 by the American astronomers <span id="ref883390"></span><a href="https://www.britannica.com/biography/William-Cranch-Bond" class="md-crosslink " data-show-preview="true">William Bond</a> and George Bond and independently by the English astronomer <span id="ref883391"></span><a href="https://www.britannica.com/biography/William-Lassell" class="md-crosslink " data-show-preview="true">William Lassell</a>. It was named for one of the <a href="https://www.britannica.com/topic/Titan-Greek-mythology" class="md-crosslink " data-show-preview="true">Titan</a>s of <a href="https://www.britannica.com/topic/Greek-mythology" class="md-crosslink autoxref " data-show-preview="true">Greek mythology</a>.</p><span class="marker MOD1 mod-inline"></span><span class="marker PREMOD2 mod-inline"></span><p class="topic-paragraph">Hyperion orbits Saturn once every 21.3 Earth days in the prograde direction at a distance of 1,481,100 km (920,300 miles), between the orbits of the moons Titan and <a href="https://www.britannica.com/topic/Iapetus-astronomy" class="md-crosslink " data-show-preview="true">Iapetus</a>. Hyperion’s orbit is unusual in that it is somewhat <a class="md-dictionary-link md-dictionary-tt-off mw" data-term="eccentric" href="https://www.merriam-webster.com/dictionary/eccentric" data-type="MW">eccentric</a> (elongated) yet inclined less than a half degree from the plane of Saturn’s equator. The nearer moon <span id="ref883392"></span><a href="https://www.britannica.com/place/Titan-astronomy" class="md-crosslink " data-show-preview="true">Titan</a> makes four circuits of Saturn for every three of Hyperion (i.e., their orbits are in a 4:3 <a class="md-dictionary-link md-dictionary-tt-off mw" data-term="dynamic" href="https://www.merriam-webster.com/dictionary/dynamic" data-type="MW">dynamic</a> resonance), and the two moons approach each other most closely when Hyperion is at the farthest point in its orbit. Under these conditions, Titan, which is the much more massive body, gives Hyperion periodic gravitational nudges that force it into a relatively eccentric orbit. Another peculiarity of Hyperion is its nonspherical shape, which is sometimes described as resembling a thick hamburger patty. Measuring 370 × 280 × 225 km (230 × 174 × 140 miles), it is the largest known moon with such a pronounced irregular shape. Its reflectance of 30 percent, which is moderately high, is consistent with the presence of some water frost on its surface. Hyperion has a reddish hue that resembles the colour of the <a class="md-dictionary-link md-dictionary-tt-off mw" data-term="enigmatic" href="https://www.merriam-webster.com/dictionary/enigmatic" data-type="MW">enigmatic</a> dark areas on the more distant moon <a href="https://www.britannica.com/topic/Iapetus-astronomy" class="md-crosslink " data-show-preview="true">Iapetus</a>; the two moons could thus harbour similar organic and <a href="https://www.britannica.com/science/carbon-chemical-element" class="md-crosslink " data-show-preview="true">carbon</a>-rich material. Hyperion’s mean <a href="https://www.britannica.com/science/density" class="md-crosslink autoxref " data-show-preview="true">density</a> is only about half that of <a href="https://www.britannica.com/science/water" class="md-crosslink " data-show-preview="true">water</a> ice, suggesting that the moon’s interior may be a loose agglomeration of ice blocks interspersed with voids. This structure may account for the remarkable “spongy” appearance of parts of Hyperion’s cratered surface in images from the <a href="https://www.britannica.com/event/Cassini-Huygens" class="md-crosslink " data-show-preview="true">Cassini</a> spacecraft. Dark material has collected inside many of the craters.</p><div class="one-good-fact-module"> </div><span class="marker MOD2 mod-inline"></span><span class="marker PREMOD3 mod-inline"></span><p class="topic-paragraph">Because of Hyperion’s shape and eccentric orbit, it does not maintain a stable rotation about a fixed <a class="md-dictionary-link md-dictionary-tt-off eb" data-term="axis" href="https://www.britannica.com/dictionary/axis" data-type="EB">axis</a>. Unlike any other known object in the <a href="https://www.britannica.com/science/solar-system" class="md-crosslink autoxref " data-show-preview="true">solar system</a>, Hyperion rotates chaotically (<em>see</em> <a href="https://www.britannica.com/science/chaos-theory" class="md-crosslink " data-show-preview="true">chaos</a>), changing its rotational characteristics over timescales as short as a month. According to theory, Hyperion can rotate in a seemingly regular manner over intervals as long as a few thousand years, followed by equally long intervals of completely chaotic tumbling, its rotation state at any specified time being completely unpredictable.</p><a class="link-module shadow-sm d-block qa-quiz-module" href="/quiz/planets-and-the-earths-moon" data-link-module-iframe-link=""> <img loading="lazy" src="https://cdn.britannica.com/74/166074-131-677298A0/Saturn-rings-planet-solar-system-Space-Art.jpg" alt="Saturn. Saturn and its rings. Second largest planet of the solar system. Space Art" class="rounded-sm mr-15" width="70" /> <div class="line-clamp clamp-5"> <div class="module-title bg-green">Britannica Quiz</div> <div class="font-weight-semi-bold mt-5">Planets and the Earth’s Moon</div> </div> </a><span class="marker MOD3 mod-inline"></span></section> <span class="md-signature"><a href="/contributor/William-B-Hubbard/3949">William B. Hubbard</a></span> <span class="marker end-of-content"></span><span class="marker after-article"></span></div> <div id="chatbot-root"></div> </div> </div> </div> <div class="ai-dialog-placeholder"></div> </div> </div> <aside class="col-md-da-320"></aside> </div> </div> </div> </div> </article></div> </div></div> </div> </main> <div id="md-footer"></div> <noscript><iframe src="//www.googletagmanager.com/ns.html?id=GTM-5W6NC8" height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript> <script type="text/javascript" id="_informizely_script_tag"> var IzWidget = IzWidget || {}; (function (d) { var scriptElement = d.createElement('script'); scriptElement.type = 'text/javascript'; scriptElement.async = true; scriptElement.src = "https://insitez.blob.core.windows.net/site/f780f33e-a610-4ac2-af81-3eb184037547.js"; var node = d.getElementById('_informizely_script_tag'); node.parentNode.insertBefore(scriptElement, node); } )(document); </script>  <script> window.ap3c = window.ap3c || {}; var ap3c = window.ap3c; ap3c.cmd = ap3c.cmd || []; ap3c.cmd.push(function() { ap3c.init('ZO4siT4cLwnykPnzZWJtd3Byb2Q', 'https://engage.email.britannica.com/'); ap3c.track({v: 0}); }); ap3c.activity = function(act) { ap3c.act = (ap3c.act || []); ap3c.act.push(act); }; var s, t; s = document.createElement('script'); s.type = 'text/javascript'; s.src = "https://engage.email.britannica.com/app.js"; t = document.getElementsByTagName('script')[0]; t.parentNode.insertBefore(s, t); </script> <script class="marketing-page-info" type="application/json"> {"pageType":"Topic","templateName":"DESKTOP","pageNumber":1,"pagesTotal":1,"pageId":279603,"pageLength":410,"initialLoad":true,"lastPageOfScroll":false} </script> <script class="marketing-content-info" type="application/json"> [] </script> <script src="https://cdn.britannica.com/mendel-resources/3-130/js/libs/jquery-3.5.0.min.js?v=3.130.14"></script> <script type="text/javascript" data-type="Init Mendel Code Splitting"> (function() { $.ajax({ dataType: 'script', cache: true, url: 'https://cdn.britannica.com/mendel-resources/3-130/dist/topic-page.js?v=3.130.14' }); })(); </script> <script class="analytics-metadata" type="application/json"> {"leg":"A","adLeg":"A","userType":"ANONYMOUS","pageType":"Topic","pageSubtype":null,"articleTemplateType":"MEDIUM","gisted":false,"pageNumber":1,"hasSummarizeButton":false,"hasAskButton":false} </script> <script type="text/javascript"> EBStat={accountId:-1,hostnameOverride:'webstats.eb.com',domain:'www.britannica.com', json:''}; </script> <script type="text/javascript"> ( function() { $.ajax( { dataType: 'script', cache: true, url: '//www.britannica.com/webstats/mendelstats.js?v=1' } ) .done( function() { try {writeStat(null,EBStat);} catch(err){} } ); })(); </script> <div id="bc-fixed-dialogue"></div> </body> </html>

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Hyperion | Saturn’s Moon, Irregular Shape & Orbit | Britannica