{"id":221752,"date":"2026-01-01T13:58:22","date_gmt":"2026-01-01T13:58:22","guid":{"rendered":"https:\/\/www.newsbeep.com\/ie\/221752\/"},"modified":"2026-01-01T13:58:22","modified_gmt":"2026-01-01T13:58:22","slug":"are-uranus-and-neptune-rock-giants-and-not-ice-giants","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/ie\/221752\/","title":{"rendered":"Are Uranus and Neptune rock giants and not ice giants?"},"content":{"rendered":"

\"UranusView larger<\/a>. | Artist\u2019s depiction of the interior of Uranus as either an ice giant<\/a> (left) or rock giant (right). A new study suggests both Uranus and Neptune<\/a> could be rock giants instead of the long-assumed ice giants. Image via Keck Institute for Space Studies\/ Chuck Carter\/ University of Zurich<\/a>.<\/p>\n

Uranus and Neptune are known as the \u201cice giants\u201d in the solar system. Scientists have long thought their interiors are composed mostly of ice. But is that accurate?
\nBoth planets might instead be rock giants, new research suggests. Their interiors would be much more rocky than previously thought.
\nThe study doesn\u2019t make any definitive conclusions. But it does expand the possibilities for what Uranus and Neptune are like on the inside.<\/p>\n

EarthSky\u2019s 2026 lunar calendar is available now. Get yours today! Makes a great gift.<\/a><\/p>\n

Uranus and Neptune: Ice giants or rock giants?<\/p>\n

Astronomers sort the planets in our solar system into three categories: rocky planets, gas giants and ice giants. Mercury, Venus, Earth and Mars are the rocky planets. Jupiter and Saturn are the gas giants. And Uranus and Neptune<\/a> are considered ice giants<\/a>, with volatile materials heavier than hydrogen and helium \u2013 such as water, ammonia or methane \u2013 in their interiors. But researchers from the University of Zurich and NCCR PlanetS in Switzerland said<\/a> on December 10, 2025, that Uranus and Neptune might be more rocky than icy on the inside. Could they be rock giants instead of ice giants?<\/p>\n

Notably, the new study doesn\u2019t say Uranus and Neptune must be either ice giants or rock giants. Rather, it makes the case that the long-held view of them being ice giants isn\u2019t the only possibility.<\/p>\n

The new peer-reviewed<\/a> paper was published online<\/a> in Astronomy & Astrophysics on December 10, 2025.<\/p>\n

Zurich Univ. press release: Uranus and Neptune might be rock giants www.news.uzh.ch\/en\/articles\/\u2026Article by Morf & Helled: www.aanda.org\/10.1051\/0004\u2026<\/p>\n

\u2014 Astronomy & Astrophysics (@aanda-journal.bsky.social)<\/a> 2025-12-19T08:28:09.935Z<\/a><\/p>\n

Challenging previous assumptions<\/p>\n

The long-held view of Uranus and Neptune is that they are ice giants. This assumes ice makes up the bulk of their interior composition, beneath their deep atmospheres. But is that the only possibility? Perhaps not.<\/p>\n

The new study expands the possible interior structures of Uranus and Neptune. It doesn\u2019t claim that any one particular model is correct. But it does increase the range of possibilities. Lead author Luca Morf<\/a> at the University of Zurich and NCCR PlanetS said<\/a> calling them ice giants might be too simplified:<\/p>\n

The ice giant classification is oversimplified, as Uranus and Neptune are still poorly understood. Models based on physics were too assumption-heavy, while empirical models are too simplistic. We combined both approaches to get interior models that are both \u2018agnostic\u2019 or unbiased and yet are physically consistent.<\/p>\n

\"SmilingLuca Morf<\/a> at the University of Zurich and NCCR PlanetS in Switzerland is the lead author of the new study about the compositions of Uranus and Neptune. Image via NCCR PlanetS<\/a>.
\nIce-rich or rock-rich?<\/p>\n

The researchers took a new approach to assessing what the interiors of Uranus and Neptune are like. First, they used a random density profile for the planetary interior. Then they calculated the planetary gravitational field that is consistent with observational data. By doing so, they could infer a possible interior composition. Lastly, they repeated the process to obtain the best possible match between the models and the observational data.<\/p>\n

The results were intriguing. They suggested that an icy interior is just one possibility. Both Uranus and Neptune could be either ice-rich or rock-rich on the inside. They also support what the researchers first proposed 15 years ago. Co-author Ravit Helled<\/a> at the University of Zurich said:<\/p>\n

It is something that we first suggested nearly 15 years ago, and now we have the numerical framework to demonstrate it.<\/p>\n

Questions remain<\/p>\n

The rock giant scenario isn\u2019t conclusive yet. Questions remain, as Morf noted:<\/p>\n

One of the main issues is that physicists still barely understand how materials behave under the exotic conditions of pressure and temperature found at the heart of a planet, this could impact our results.<\/p>\n

Uranus and Neptune could still be either ice giants or rock giants. Helled added:<\/p>\n

Both Uranus and Neptune could be rock giants or ice giants depending on the model assumptions. Current data are currently insufficient to distinguish the two, and we therefore need dedicated missions to Uranus and Neptune that can reveal their true nature.<\/p>\n

\"TwoView larger<\/a>. | NASA\u2019s Voyager 2<\/a> spacecraft captured these views of Uranus and Neptune during its flybys of the planets in the late 1980s. A new study suggests both planets might be rock giants instead of ice giants. Image via NASA\/ JPL-Caltech\/ B. J\u00f3nsson\/ NOIRLab<\/a>.
\nNew clues about Uranus\u2019 and Neptune\u2019s magnetic fields<\/p>\n

The findings also shed new light on Uranus\u2019 and Neptune\u2019s unusual magnetic fields. They are more complex than Earth\u2019s, since they have more than two poles. Earth, on the other hand, simply has a magnetic North Pole and magnetic South Pole. As Helled explained:<\/p>\n

Our models have so-called \u2018ionic water\u2019 layers which generate magnetic dynamos in locations that explain the observed non-dipolar magnetic fields. We also found that Uranus\u2019 magnetic field originates deeper than Neptune\u2019s.<\/p>\n

There are currently no new missions being developed yet to return to Uranus or Neptune. The last visit was by Voyager 2<\/a> in the late 1980s. So, in the meantime scientists will continue to study the data from the old Voyager missions and from current telescopes to try to better understand these mysterious worlds.<\/p>\n

Bottom line: Are Uranus and Neptune really ice giants as scientists have long thought? A new study suggests they might be much more rocky instead of icy on the inside.<\/p>\n

Source: Icy or rocky? Convective or stable? New interior models of Uranus and Neptune<\/a><\/p>\n

Via University of Zurich<\/a><\/p>\n

Read more: Are Uranus and Neptune hiding oceans of water?<\/a><\/p>\n

Read more: True colors of Uranus and Neptune in newly processed images<\/a><\/p>\n

Paul Scott Anderson
\n View Articles<\/a><\/p>\n

About the Author:<\/p>\n

Paul Scott Anderson has had a passion for space exploration that began when he was a child when he watched Carl Sagan\u2019s Cosmos. He studied English, writing, art and computer\/publication design in high school and college. He later started his blog The Meridiani Journal in 2005, which was later renamed Planetaria. He also later started the blog Fermi Paradoxica, about the search for life elsewhere in the universe.
\n
\nWhile interested in all aspects of space exploration, his primary passion is planetary science and SETI. In 2011, he started writing about space on a freelance basis with Universe Today. He has also written for SpaceFlight Insider and AmericaSpace and has also been published in The Mars Quarterly. He also did some supplementary writing for the iOS app Exoplanet.
\n
\nHe has been writing for EarthSky since 2018, and also assists with proofing and social media.<\/p>\n","protected":false},"excerpt":{"rendered":"View larger. | Artist\u2019s depiction of the interior of Uranus as either an ice giant (left) or rock…\n","protected":false},"author":2,"featured_media":221753,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7],"tags":[101279,61,60,3631,114635,82,247,5435],"class_list":["post-221752","post","type-post","status-publish","format-standard","has-post-thumbnail","category-science","tag-ice-giant","tag-ie","tag-ireland","tag-planets","tag-rock-giant","tag-science","tag-space","tag-uranus-and-neptune"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/221752","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/comments?post=221752"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/posts\/221752\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media\/221753"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/media?parent=221752"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/categories?post=221752"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/ie\/wp-json\/wp\/v2\/tags?post=221752"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}