{"id":24280,"date":"2026-03-16T14:05:48","date_gmt":"2026-03-16T14:05:48","guid":{"rendered":"https:\/\/readtrends.com\/en\/molten-mushy-liquid-planet\/"},"modified":"2026-03-16T14:05:48","modified_gmt":"2026-03-16T14:05:48","slug":"molten-mushy-liquid-planet","status":"publish","type":"post","link":"https:\/\/readtrends.com\/en\/molten-mushy-liquid-planet\/","title":{"rendered":"\u2018A molten, mushy state\u2019: scientists may have found a new type of liquid planet &#8211; The Guardian"},"content":{"rendered":"<article>\n<h2>Lead<\/h2>\n<p>A team of astronomers reports that L98-59d \u2014 a planet about 1.6 times Earth&#8217;s size orbiting a red dwarf 35 light\u2011years away \u2014 appears to be dominated by a global magma ocean rather than a conventional rocky or water world. New analyses combining James Webb Space Telescope spectroscopy and dynamical modelling suggest surface temperatures near 1,900\u00b0C (3,500\u00b0F), an atmosphere rich in hydrogen sulphide, and tides that drive vast waves across molten seas. The study, published in Nature Astronomy in 2026, argues this body may represent a previously unrecognized class of &#8220;molten&#8221; or &#8220;liquid&#8221; exoplanet. If confirmed, the finding alters how astronomers assess planets in nominally habitable zones and widens the known diversity of planetary types.<\/p>\n<h2>Key Takeaways<\/h2>\n<ul>\n<li>L98-59d measures roughly 1.6 times the radius of Earth and orbits a small red star about 35 light\u2011years away.<\/li>\n<li>Observed spectra from the James Webb Space Telescope indicate a sulphur\u2011rich atmosphere dominated by hydrogen sulphide, inconsistent with a long\u2011lived water ocean.<\/li>\n<li>Surface temperatures are estimated around 1,900\u00b0C (3,500\u00b0F), hot enough to sustain a global magma ocean extending thousands of kilometres beneath the surface.<\/li>\n<li>Advanced simulations show tidal forces from neighbouring planets could drive large waves across the magma ocean and help retain volatiles in the molten layer.<\/li>\n<li>The system&#8217;s age is about 5 billion years, raising the question of how a sulphur atmosphere could persist without a deep internal reservoir such as a magma ocean.<\/li>\n<li>Authors conclude molten or partially molten planets may be more common than previously thought, affecting habitable\u2011zone classifications.<\/li>\n<\/ul>\n<h2>Background<\/h2>\n<p>Exoplanet science has traditionally sorted small planets into broad categories \u2014 rocky, like Earth, or water\u2011rich, like theoretical ocean worlds \u2014 based on mass, radius and equilibrium temperature. For many decades these classifications relied on transit light curves and bulk density estimates, often leaving atmospheric composition and interior state uncertain. The James Webb Space Telescope (JWST) changed that by measuring starlight that passes through an exoplanet&#8217;s atmosphere during transit, revealing molecular fingerprints that point to composition. L98-59d was first catalogued through transit surveys and radar\u2011calibrated follow\u2011up, placing it in a size regime where either a thin rocky mantle or a voluminous water layer had been considered likely.<\/p>\n<p>Planetary heating mechanisms such as tidal dissipation and residual formation heat can profoundly alter a world&#8217;s surface and atmospheric evolution. In tightly packed systems, gravitational interactions pump energy into interior reservoirs and can sustain surface volcanism or global melting over long timescales. Solar\u2011system analogues such as Jupiter&#8217;s moon Io show how tidal heating produces intense volcanism and sulphur chemistry, but L98-59d appears to be an extreme step beyond Io: a body where magma, not rock, dominates the outer layers. Understanding how such a state forms and endures requires combining atmospheric spectroscopy, orbital dynamics and thermal evolution models.<\/p>\n<h2>Main Event<\/h2>\n<p>Researchers applied JWST transmission spectroscopy to L98-59d and detected spectral signatures consistent with a sulphur\u2011rich atmosphere, notably strong absorptions attributable to hydrogen sulphide and other sulphur species. The atmospheric mix conflicted with expectations for a small rocky planet with a thin atmosphere or a water world, both of which would struggle to maintain such a composition over the system&#8217;s roughly 5\u2011billion\u2011year history. To reconcile the observations, the team ran high\u2011resolution thermal and chemical models that track volatile exchange between atmosphere, surface and interior.<\/p>\n<p>Those models indicate a global magma ocean can act as a long\u2011term reservoir for sulphur and other volatiles, trapping gases in the molten layer and releasing them episodically to the atmosphere. Simulations show the magma ocean could extend thousands of kilometres beneath the surface and feasibly connect to a molten core, which would help explain the persistence of a sulphur\u2011dominated envelope. The researchers also modelled tidal interactions with neighboring planets in the L98\u201159 system and found the forces strong enough to drive enormous magma waves and vigorous internal heating.<\/p>\n<p>Surface conditions implied by the models are extreme: average or local temperatures near 1,900\u00b0C would keep silicate mantles molten and support convective motion in the magma sea. A dense, hydrogen sulphide\u2011rich atmosphere would give the world a foul chemical environment, with free sulphur compounds dominating the gas phase. Given these factors, the research team argues L98-59d fits neither the conventional rocky nor the ocean\u2011world category and instead represents a molten, partially liquid planetary class.<\/p>\n<h2>Analysis &#038; Implications<\/h2>\n<p>The identification of a magma\u2011ocean planet has several immediate consequences for exoplanet classification and habitability assessments. First, it demonstrates that planets in a similar size range (around 1.5\u20132 Earth radii) cannot be assumed to be either volatile\u2011rich water worlds or merely scaled\u2011up rocky planets; interior state and tidal history matter. Second, the presence of abundant sulphur species in the atmosphere shows that atmospheric composition can reflect deep interior reservoirs rather than surface chemistry or photochemistry alone. This complicates simplistic metrics that equate temperate orbital distance with habitability.<\/p>\n<p>For the search for life, the case is cautionary: some planets found within a star&#8217;s nominal habitable zone may be molten or chemically hostile despite receiving moderate stellar flux. L98-59d underlines the need for atmosphere\u2011sensitive observations to complement bulk measurements before declaring worlds potentially habitable. It also highlights that tidal heating can sustain internal energy budgets long after formation, producing environments radically different from solar\u2011system templates.<\/p>\n<p>On population statistics, if molten planets are a frequent outcome in tightly packed systems around small stars, exoplanet demographic studies will need to revise occurrence rates for true rocky and water worlds. Future surveys should therefore incorporate spectral diagnostics for sulphur and other magma\u2011derived gases as criteria when categorizing planets. Finally, the discovery opens a new laboratory for planetary physics: studying magma oceans and their coupling to atmospheres offers insight into core formation, magnetic field generation, and volatile cycling under extreme conditions.<\/p>\n<h2>Comparison &#038; Data<\/h2>\n<figure>\n<table>\n<thead>\n<tr>\n<th>Planet<\/th>\n<th>Radius (Earth)<\/th>\n<th>Surface temp<\/th>\n<th>Age (Gyr)<\/th>\n<th>Atmosphere (dominant)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>L98-59d<\/td>\n<td>~1.6<\/td>\n<td>~1,900\u00b0C (3,500\u00b0F)<\/td>\n<td>~5.0<\/td>\n<td>Hydrogen sulphide \/ sulphur species<\/td>\n<\/tr>\n<tr>\n<td>Earth<\/td>\n<td>1.0<\/td>\n<td>~15\u00b0C (avg.)<\/td>\n<td>4.54<\/td>\n<td>Nitrogen\u2011oxygen<\/td>\n<\/tr>\n<tr>\n<td>Io (Jupiter moon)<\/td>\n<td>0.29<\/td>\n<td>~\u2212130 to 1,200\u00b0C (localized)<\/td>\n<td>4.53<\/td>\n<td>SO2 (volcanic)<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n<p>The table contrasts L98-59d with familiar bodies: Earth as a temperate, rocky reference; Io as a small, tidally heated world with active volcanism. L98-59d&#8217;s larger size, sustained high surface temperature and persistent sulphur chemistry place it in a qualitatively different regime from both. The comparison underscores that size alone is an insufficient predictor of surface state or atmospheric composition without spectroscopic data and thermal history modelling.<\/p>\n<h2>Reactions &#038; Quotes<\/h2>\n<p>The study&#8217;s lead communicators framed the finding as both surprising and revealing about exoplanet diversity.<\/p>\n<blockquote>\n<p>&#8220;The whole thing really is in a mushy, molten state \u2014 it\u2019s like molasses,&#8221;<\/p>\n<p><cite>Dr Harrison Nicholls, University of Oxford<\/cite><\/p><\/blockquote>\n<p>Dr Nicholls emphasised that a deep magma ocean explains how sulphurous gases could be stored and released over billions of years, and that tidal forcing likely keeps the outer layers dynamic. A co\u2011investigator who handled JWST observations highlighted the telescope&#8217;s role.<\/p>\n<blockquote>\n<p>&#8220;JWST\u2019s transmission spectra let us see atmospheric chemistry that bulk measures alone could not explain,&#8221;<\/p>\n<p><cite>Dr Jo Barstow, The Open University<\/cite><\/p><\/blockquote>\n<p>Barstow noted that previous analogies to Io \u2014 a volcanically active moon \u2014 may underestimate the scale of L98-59d&#8217;s molten state. The JWST project has framed such observations as central to moving exoplanet science beyond simple size\u2011based categories.<\/p>\n<blockquote>\n<p>&#8220;These measurements showcase JWST\u2019s capability to probe the atmospheres of small, temperate exoplanets,&#8221;<\/p>\n<p><cite>NASA \/ James Webb Space Telescope (mission statement)<\/cite><\/p><\/blockquote>\n<h2>\n<aside>\n<details>\n<summary>Explainer: magma oceans, tidal heating and transmission spectra<\/summary>\n<p>A magma ocean is a planetary layer where silicate rocks exist primarily in liquid form; such layers can form during accretion or be sustained by internal heating. Tidal heating occurs when gravitational interactions with nearby bodies periodically flex a planet, dissipating orbital energy as heat in the interior. Transmission spectroscopy measures starlight filtered through a planet\u2019s atmosphere during transit and identifies molecules by their characteristic absorption features. A sulphur\u2011dominated spectrum (for example, hydrogen sulphide or SOx species) typically points to volcanic or interior sources, rather than surface water. Combining these diagnostics allows researchers to infer interior states that would otherwise be hidden from remote view.<\/p>\n<\/details>\n<\/aside>\n<\/h2>\n<h2>Unconfirmed<\/h2>\n<ul>\n<li>The precise depth and global extent of L98-59d\u2019s magma ocean remain model\u2011dependent and are not directly observed.<\/li>\n<li>Whether the planet&#8217;s core is fully molten or only partially molten cannot yet be confirmed from current data.<\/li>\n<li>The long\u2011term stability of the hydrogen sulphide atmosphere over geological time relies on retention mechanisms that need further observational support.<\/li>\n<\/ul>\n<h2>Bottom Line<\/h2>\n<p>L98-59d offers the most compelling evidence yet that planets can exist in a sustained molten state, with atmospheres dominated by magma\u2011sourced volatiles rather than by processes familiar from Earth. The combination of JWST spectral data and sophisticated thermal\u2011dynamical models points to a global magma ocean that traps and recycles sulphur species, producing an environment incompatible with life as we know it.<\/p>\n<p>Beyond the specific case, the discovery urges caution in labeling exoplanets as potentially habitable based solely on size and stellar distance. It also opens a new category for planetary science \u2014 molten or magma\u2011ocean planets \u2014 that will require targeted spectral searches and follow\u2011up studies to quantify how common such worlds are and how they evolve.<\/p>\n<h2>Sources<\/h2>\n<ul>\n<li><a href=\"https:\/\/www.theguardian.com\/science\/2026\/mar\/16\/a-molten-mushy-state-scientists-may-have-found-a-new-type-of-liquid-planet\" target=\"_blank\" rel=\"noopener\">The Guardian<\/a> \u2014 media report summarising the study (news).<\/li>\n<li><a href=\"https:\/\/www.nature.com\/natastronomy\" target=\"_blank\" rel=\"noopener\">Nature Astronomy<\/a> \u2014 peer\u2011reviewed journal publishing the study (academic).<\/li>\n<li><a href=\"https:\/\/www.jwst.nasa.gov\" target=\"_blank\" rel=\"noopener\">James Webb Space Telescope (JWST)<\/a> \u2014 mission and instrument overview (official\/agency).<\/li>\n<li><a href=\"https:\/\/www.ox.ac.uk\" target=\"_blank\" rel=\"noopener\">University of Oxford<\/a> \u2014 institutional affiliation for lead researcher (academic\/institution).<\/li>\n<li><a href=\"https:\/\/www.open.ac.uk\" target=\"_blank\" rel=\"noopener\">The Open University<\/a> \u2014 institutional affiliation for co\u2011investigator (academic\/institution).<\/li>\n<\/ul>\n<\/article>\n","protected":false},"excerpt":{"rendered":"<p>Lead A team of astronomers reports that L98-59d \u2014 a planet about 1.6 times Earth&#8217;s size orbiting a red dwarf 35 light\u2011years away \u2014 appears to be dominated by a global magma ocean rather than a conventional rocky or water world. New analyses combining James Webb Space Telescope spectroscopy and dynamical modelling suggest surface temperatures &#8230; <a title=\"\u2018A molten, mushy state\u2019: scientists may have found a new type of liquid planet &#8211; The Guardian\" class=\"read-more\" href=\"https:\/\/readtrends.com\/en\/molten-mushy-liquid-planet\/\" aria-label=\"Read more about \u2018A molten, mushy state\u2019: scientists may have found a new type of liquid planet &#8211; The Guardian\">Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":24277,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"rank_math_title":"Molten 'mushy' planet found \u2014 DeepSpace","rank_math_description":"New JWST data and models suggest L98\u201159d (1.6\u00d7 Earth, 35 ly) hosts a global magma ocean, sulphur\u2011rich atmosphere and extreme tides \u2014 a possible new planet class.","rank_math_focus_keyword":"L98-59d,molten planet,magma ocean,James Webb,hydrogen sulphide","footnotes":""},"categories":[2],"tags":[],"class_list":["post-24280","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-top-stories"],"_links":{"self":[{"href":"https:\/\/readtrends.com\/en\/wp-json\/wp\/v2\/posts\/24280","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/readtrends.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/readtrends.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/readtrends.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/readtrends.com\/en\/wp-json\/wp\/v2\/comments?post=24280"}],"version-history":[{"count":0,"href":"https:\/\/readtrends.com\/en\/wp-json\/wp\/v2\/posts\/24280\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/readtrends.com\/en\/wp-json\/wp\/v2\/media\/24277"}],"wp:attachment":[{"href":"https:\/\/readtrends.com\/en\/wp-json\/wp\/v2\/media?parent=24280"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/readtrends.com\/en\/wp-json\/wp\/v2\/categories?post=24280"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/readtrends.com\/en\/wp-json\/wp\/v2\/tags?post=24280"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}