--- description: A longstanding mystery about the planet's tilt gets a new explanation. title: A Longstanding Mystery Involving Uranus' Tilted Orbit Gets a New Explanation image: https://static.time.com/v3/assets/bltea6093859af6183b/bltdf6a9285e6dff820/698a364b457a520602d66e45/planet-uranus-sideways-tilt-orbit-science.jpg?branch=production&width=3840&quality=75&auto=webp&crop=16:9 ---  * [Science](/section/science/) ## Science Update your preferences in [Account Settings](/account/preferences/) Close * [Space](/tag/space/) ## Space Update your preferences in [Account Settings](/account/preferences/) Close # A Longstanding Mystery Involving Uranus' Tilted Orbit Gets a New Explanation  by [Jeffrey Kluger](/author/jeffrey-kluger/)  ## Jeffrey Kluger Update your preferences in [Account Settings](/account/preferences/) Close Editor at Large Oct 7, 2022 9:33 PM CUT  An impression of the green ice giant planet, Uranus. It is unusual in that it has a very pale, almost featureless atmosphere, and an axial tilt close to 100 degrees. An impression of the green ice giant planet, Uranus. It is unusual in that it has a very pale, almost featureless atmosphere, and an axial tilt close to 100 degrees.Getty Images/Science Photo Libra—Science Photo Library  by [Jeffrey Kluger](/author/jeffrey-kluger/)  ## Jeffrey Kluger Update your preferences in [Account Settings](/account/preferences/) Close Editor at Large Oct 7, 2022 9:33 PM CUT Uranus is one of the least explored planets in the solar system, with just a single barnstorming visit by Voyager 2 in 1986\. If ever there was a world that deserves more attention than that, however, Uranus is it, if only because it is such a cosmic odd-ball. --- ### More from TIME --- Easily Uranus’ strangest feature is the fact that it orbits on its side, lying at a 98-degree angle, with its North and South poles facing effectively East and West. Astronomers have always attributed the planet’s peculiar posture to a long-ago collision with a large passing body. But as [Space.com reports](https://www.space.com/uranus-tilt-from-lost-moon-not-impact "undefined"), a new paper accepted for publication in the journal _A_ _stronomy and Astrophysics,_ and [posted to the preprint site arXiv.org,](https://arxiv.org/abs/2209.10590 "undefined") offers a new and different theory. A lingering problem with the giant impact explanation for Uranus’ angle is that the entire early solar system was a shooting gallery of whizzing planets and moons which should have knocked other planets similarly cockeyed. And yet, Uranus alone orbits sideways. According to the new paper, it wasn’t an impact that tipped Uranus at all. Rather, it argues, a massive moon fell into orbit around the planet and gravitationally destabilized it. Using computer models, the researchers calculate that over time, the moon would have tilted Uranus to an angle of 80 degrees. At this point, the planet-moon pair would have entered a chaotic gravitational dance, pulling Uranus even further sideways and ending with the moon crashing into the planet, vanishing from history and freezing Uranus at its current 98-degree angle. The theory is a sound one, at least as far as computer models can prove, and it could get a further test sometime after 2030\. That’s when [China plans to launch its Tianwen-4 spacecraft](https://www.space.com/china-probes-jupiter-uranus-same-launch "undefined"), which will make twin flybys first of Jupiter and then of Uranus, at last giving the sideways planet another up-close look. _This story originally appeared in TIME Space, our weekly newsletter covering all things space._ [_You can sign up here._](https://time.com/newsletters/ "undefined") ```json [{"@context":"https://schema.org","@type":"NewsArticle","@id":"https://time.com/6220649/why-uranus-has-a-tilted-orbit/","mainEntityOfPage":{"@type":"WebPage","@id":"https://time.com/6220649/why-uranus-has-a-tilted-orbit/"},"headline":"A Longstanding Mystery Involving Uranus' Tilted Orbit Gets a New Explanation","datePublished":"2022-10-07T21:33:04.000Z","dateModified":"2026-02-24T14:52:07.388Z","description":"A new computer model explains why the planet has a tilted orbit","url":"https://time.com/6220649/why-uranus-has-a-tilted-orbit/","keywords":["Space","healthscienceclimate"],"thumbnailUrl":"https://static.time.com/v3/assets/bltea6093859af6183b/bltdf6a9285e6dff820/698a364b457a520602d66e45/planet-uranus-sideways-tilt-orbit-science.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","author":[{"@type":"Person","name":"Jeffrey Kluger","jobTitle":"Editor at Large","url":"https://time.com/author/jeffrey-kluger/"}],"articleSection":"Science","image":[{"@type":"ImageObject","url":"https://static.time.com/v3/assets/bltea6093859af6183b/bltdf6a9285e6dff820/698a364b457a520602d66e45/planet-uranus-sideways-tilt-orbit-science.jpg?branch=production&width=1200&quality=75&auto=webp&crop=1200:675&height=675","width":1200,"height":675,"headline":"Artwork of Uranus","caption":"Artwork of Uranus","creditText":"Getty Images/Science Photo Libra—Science Photo Library","representativeOfPage":true}],"publisher":{"@type":"Organization","name":"Time","url":"https://time.com/","logo":{"@type":"ImageObject","url":"https://time.com/images/logo.png","width":528,"height":156},"foundingDate":"March 3, 1923","sameAs":["https://www.facebook.com/time","https://www.instagram.com/time/?hl=en","https://twitter.com/time","https://www.pinterest.com/timemagazine"]}},{"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"item":{"@id":"/section/science/","name":"Science"}},{"@type":"ListItem","position":2,"item":{"@id":"/tag/space/","name":"Space"}},{"@type":"ListItem","position":3,"item":{"@id":"https://time.com/6220649/why-uranus-has-a-tilted-orbit/","name":"A Longstanding Mystery Involving Uranus' Tilted Orbit Gets a New Explanation"}}]},{"@context":"https://schema.org","@type":"VideoObject","name":"Scientists Solve the Mystery Behind the Oumuamua 'Alien Spacecraft' Comet","description":"In the years since Oumuamua’s discovery, no one has yet explained how, in fact, the object defied traditional cometary physics and hit the gas as it was leaving our solar system. 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